Hydraulic Power Unit Product Information Manual Model 506.82 Model 506.92 011-770-700 F Copyright information Trademark information © 2000 MTS Systems Corporation. All rights reserved. MTS is a registered trademark of MTS Systems Corporation. DTE is a registered trademark of Mobil Corporation. Tellus is a registered trademark of Shell Oil Corporation. Contact information Publication information MTS Systems Corporation 14000 Technology Drive Eden Prairie, Minnesota 55344-2290 USA Toll Free Phone: 800-328-2255 (within the U.S. or Canada) Phone: 952-937-4000 (outside the U.S. or Canada) Fax: 952-937-4515 E-mail: info@mts.com http://www.mts.com Manual Part Number Publication Date 011-770-700 F June 1997 Table of Contents Section 1 1.1 1.2 Section 2 2.1 2.2 2.3 Section 3 3.1 3.1.1 3.1.1.1 3.1.1.2 3.1.2 3.1.3 3.1.3.1 3.1.3.2 3.1.3.3 3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.3 3.3.1 3.3.2 3.3.3 Section 4 4.1 4.2 4.2.1 4.2.2 4.3 Introduction Functional Description............................................................................. 1-2 Specifications........................................................................................... 1-3 Operation Controls and Indicators............................................................................ 2-1 Operation Procedures .............................................................................. 2-3 Supercharge Pump Operation .................................................................. 2-5 Service Maintenance Procedures.......................................................................... 3-1 Filters ................................................................................................ 3-2 High-Pressure Filter Replacement ................................................ 3-3 Low-Pressure Filter Replacement ................................................. 3-4 Hydraulic ................................................................................. Fluid 3-5 Accumulators .................................................................................... 3-7 Precharge Pressure-Checking Intervals......................................... 3-7 Precharging the Accumulators ..................................................... 3-8 Changing the Accumulator Seals.................................................. 3-8 Service Adjustments................................................................................. 3-9 Adjusting the Output Pressure...........................................................3-10 Dual-Temperature Switch Adjustments ..............................................3-12 Low-Level Switch Adjustment...........................................................3-13 Main Pump Low-Inlet Pressure Switch Adjustment ...........................3-14 Starter Assembly.....................................................................................3-15 Abnormal HPS Shutdown.................................................................3-16 Fuse Replacement .............................................................................3-16 PLC ...................................................................................... Service 3-17 Installation Hydraulic Connections............................................................................ 4-2 Electrical Connections.............................................................................. 4-3 Transformer Wiring ........................................................................... 4-4 Input Power ...................................................................................... 4-5 Cooling Water Connections ..................................................................... 4-6 Table of Contents i Section 5 5.1 5.2 5.2.1 5.2.2 Theory of Operation Hydraulic Operation................................................................................ 5-1 Electrical Operation ................................................................................. 5-3 Control.............................................................................................. 5-4 Interlocks .......................................................................................... 5-5 Index List of Figures Figure 2-1 Figure 3-1 Figure 3-2 Figure 3-3 Figure 3-4 Figure 3-5 Figure 4-1 Figure 4-2 Figure 4-3 Figure 4-4 Figure 4-5 Figure 5-1 Figure 5-2 Controls and Indicators ........................................................................... 2-1 Location of Maintenance Components (HPS Side View) ........................... 3-1 Location of Accumulators ........................................................................ 3-7 Location of Adjustment Components (HPS Side View) ............................. 3-9 Models 506.82/.92 Starter Assembly (Typical)..........................................3-15 Fixed Controller with Remote Control Modules......................................3-16 Location of Remote Control Connector.................................................... 4-1 Hydraulic Connections............................................................................ 4-2 Models 506.82 and 506.92 Starter Assemblies ............................................ 4-3 Standard Transformer Wiring Configuration............................................. 4-4 Typical Multi-Tap Transformer Wiring Configuration............................... 4-4 Hydraulic Block Diagram ........................................................................ 5-1 Typical Electrical Schematic ..................................................................... 5-7 List of Tables Table 1-1 Table 1-2 Table 2-1 Table 3-1 Table 3-2 Table 3-3 Table 3-4 Table 3-5 ii Cooling Water Flow Requirements .......................................................... 1-3 HPS Specifications ................................................................................... 1-3 Controls and Indicators............................................................................ 2-2 Maintenance Schedule ............................................................................. 3-2 Starter Assembly Fuse Values..................................................................3-16 Fixed Controller Output Indicators..........................................................3-18 Fixed Controller Input Indicators............................................................3-18 Remote Control Module Output Indicators .............................................3-19 Table of Contents Section 1 Introduction Definition The Model 506.82/.92 Hydraulic Power Unit (HPU) uses two variablevolume (pressure compensated) main pumps, with a pressurized (supercharged) hydraulic fluid inlet, to provide pressure to systems with various flow requirements. The HPU is designed to be used with servocontrolled, electro-hydraulic systems. Model 506.82/.92 Hydraulic Power Unit Introduction 1-1 1.1 Functional Description Front panel controls and indicators Front panel controls on the HPU include local operating controls and two running time meters. Front panel indicators show power on, low oil level, fluid over-temperature, motor overload and dirty filter conditions. Pressure output The output pressure is controlled by an adjustment on the main pumps and is monitored by the output pressure gage. An adjustable back-up relief valve limits output pressure by porting fluid back to the reservoir when the output pressure rises above the relief valve setting. High/low pressure operation is controlled by the high/low solenoid valves. These valves control the main pressure control (pressure compensator) vent ports and the backup relief valve vent port. Pressure accumulation The pressure accumulator smoothes the HPU output pressure and provides additional hydraulic flow for dynamic actuator demands. It is precharged with dry nitrogen to a pressure proportional to HPU output pressure. The slow turn-on accumulator slows the rate at which the backup relief valve shifts from low to high pressure. Temperature control A temperature gage indicates hydraulic fluid temperature. An oil-to-water heat exchanger controls the fluid temperature. When the temperature exceeds a preset limit, a temperature sensitive switch turns off the HPU and lights the front panel Over-Temperature indicator. Fluid level indication A transparent gage indicates the level of hydraulic fluid in the HPU reservoir. A low-level switch automatically turns off the HPU and lights the front panel Low Oil Level indicator if hydraulic fluid drops below a preset level. Programmable logic controller The PLC (programmable logic controller) located in the starter assembly performs logic functions. The I/O (input/output) section of the PLC provides an interface for various signals received from or sent to external devices. An optional module can be added to the PLC if remote control of the HPU is required. This module provides the additional output indicators needed for the remote control option. Introduction 1-2 1.2 Specifications The required water pressure between the input and the output of the heat exchanger is 30 to 45 psi (0.2 to 0.3 MPa). The maximum allowable pressure is 120 psig (0.8 psid). The flow rate (±20%) at a given temperature is shown in the table below. Cooling water specifications Table 1-1. Cooling Water Requirements Cooling Water Inlet Required Water Flow Temperature 506.82B 506.92B 60°F (15.5°C) 30 gpm (114 l/min) 35 gpm (132 l/min) 65°F (18.5°C) 35 gpm (132 l/min) 42 gpm (159 l/min) 70°F (21.0°C) 40 gpm (151 l/min) 51 gpm (193 l/min) 75°F (24.0°C) 46 gpm (174 l/min) 67 gpm (254 l/min) 80°F (26.5°C) 54 gpm (204 l/min) 90 gpm (341 l/min) 85°F (29.5°C) 70 gpm (269 l/min) 120 gpm (454 l/min) 90°F (32.0°C) 90 gpm (346 l/min) 160 gpm (606 l/min) General HPU specifications Table 1-2 lists the specifications for the Model 506.82/.92 Hydraulic Power Unit. Table 1-2. HPU Specifications Parameter Model 506.82B Model 506.92B Maximum continuous pressure 3000 psi (20.7 MPa) 3000 psi (20.7 MPa) Maximum flow capacity (60 Hz) 150 gpm (568 l/min) 200 gpm (757 l/min) Maximum flow capacity (50 Hz) 150 gpm (568 l/min) 185 gpm (710 l/min) Noise rating at 3 ft. (0.9 m) 90 dBa 90 dBa Maximum full to top plate (no air) 571 gal ( 2161l) 571 gal ( 2161l) Nominal running level, 28 in. (711 mm) above tank bottom 463 gal (1753 l) 463 gal (1753 l) Low-pressure filtration, absolute/nominal 3.0/0.45 microns 3.0/0.45 microns High-pressure filtration 10 microns 10 microns Pressure (SAE 4 bolt) -24 (1), -32 (1) -24 (1), -32 (1) Return (SAE 4 bolt) -24 (1), -32 (1) -24 (1), -32 (1) Drain (37° flare) -16 (1), -12 (1), -8 (2) -16 (1), -12 (1), -8 (2) 150 hp (112 kW) 200 hp (150 kW) Reservoir capacity: Fluid hose connections:* Main pump motor power rating (2 each) Introduction 1-3 Table 1-2. HPU Specifications (Continued) Parameter Supercharge pump motor power rating Model 506.82B Model 506.92B 25 hp (19 kW) 40 hp (30 kW) Inrush 575 A 775 A Continuous 395 A 535 A Starter type Wye-delta Wye-delta 24 V external hydraulic control amps (with optional remote control) 6.8 A 6.8 A BTU per hour 760,000 1,020,000 Kilocalories per hour 192,000 257,600 3-phase current 460V/60 Hz:† Maximum cooling water heat load: Atmospheric heat load (BTU per hour) 56,900 87,800 Atmospheric heat load (Kilocalories per hour) 14,400 22,200 Water inlet/outlet size 1.5 in. (38 mm) NPT 2 in. (51 mm) NPT Maximum ambient operating temperature 104°F (40°C) 104°F (40°C) Minimum ambient operating temperature 40°F (4.4°C) 40°F (4.4°C) Height with casters 78 in. (1981 mm) 78 in. (1981 mm) Length 111 in. (2819 mm) 111 in. (2819 mm) Width 68 in. (1727 mm) 68 in. (1727 mm) Weight with oil 12,500 lb (5669 kg) 12,500 lb (5669 kg) * The number of connections are shown in parentheses. † Currents listed are typical theoretical values based on data outlined in the NEPA-70 (national electrical code). Supply conductors and disconnect switch sizing must be done using the customer’s local and state codes. Specifications subject to change without notice. Contact MTS for verification of any critical specifications. Introduction 1-4 Section 2 Operation 2.1 Controls and Indicators Figure 2-1 and Table 2-1 identify and describe HPU controls and indicators. Fluid Level Gage Temperature Gage (These gages are located on the HPS rear panel) VW-G041C Figure 2-1. Controls and Indicators Operation 2-1 Table 2-1. Controls and Indicators Control/Indicator Power On indicator* Description The Power On indicator lights to indicate that electrical power is applied to the HPU. Emergency Stop switch This switch operates in both local and remote control and is used during emergency situations only. When pressed, it immediately shuts down the HPU (the supercharge pump may continue to run briefly to supply the main pumps until they fully stop). Local Mode switch If the Local Mode switch is activated, you can operate the HPU with the front panel controls. If it is not activated, use a remote control device to operate the HPU. Activation lights an LED in the upper right corner of the switch. Start switch Pressing Start sequences supercharge and main motors on, then applies low pressure when in local control. High Pressure Pressing High Pressure applies high pressure in local control. Start must be pressed before applying high pressure. Activation lights an LED in the upper right corner of the switch. The LED also lights if high pressure is requested remotely. Stop switch When Stop is pressed (in either local or remote mode), the HPU first ramps to low pressure and then goes to zero pressure. The supercharge pump continues to run for approximately 15 seconds. Reset switch This switch resets the interlock circuit if the condition causing the interlock has been corrected. Low Oil Level indicator When this indicator lights, the hydraulic fluid level has dropped below a preset value. Fluid level gage This gage indicates the level of hydraulic fluid in the reservoir. Over-Temperature indicator When this indicator lights, hydraulic fluid temperature has exceeded a preset value. Temperature gage This gage indicates the temperature of the hydraulic fluid in the HPU reservoir. Dirty Filter indicator When this indicator lights, the low-pressure filter needs replacement. See Subsection 3.1.1. Pump 1 Select Pressing this switch selects Pump 1 for operation. Activation lights an LED in the upper right corner of the switch. Pump 2 Select Pressing this switch selects Pump 2 for operation. Activation lights an LED in the upper right corner of the switch. Hour Meter Pump No. 1 This front panel meter indicates the total operating hours of pump 1. Hour Meter Pump No. 2 This front panel meter indicates the total operating hours of pump 2. Operation 2-2 2.2 Operation Procedures This section provides the local and remote operating procedures for the 506.82/.92 Hydraulic Power Unit. ! WARNING Do not start the HPU if the servovalve command is not equal to feedback (that is, zero balanced). Failure to do this can result in sudden actuator movement which may cause injury to persons and/or damage to equipment. Ensure that the system is at zero balance before starting the HPU. Before you begin Before you begin operation complete the following steps: 1. Make sure that the external hydraulic system is ready for operation. 2. Press the Pump 1 Select or Pump 2 Select switch to select main pump operation. NOTE Local operation The Dirty Filter indicator may light during a cold-start. It should turn off when the HPU reaches its normal operating temperature. If the indicator fails to turn off, correct the condition (Subsection 3.1.1.2) and press Reset. To operate the HPU in local control mode complete the following steps: 1. Press the Local Mode switch to run the HPU in local control. Activating this switch lights an LED in its upper right corner. 2. Apply electrical power to the HPU (the Power On indicator will light). 3. Press Reset (must be pressed whenever electrical power to the HPS has been interrupted). 4. Press the Start switch to apply low pressure to the system. 5. Check the HPU and external hydraulic system for leaks and unusual sounds. 6. Press the High Pressure to apply high pressure to the system. 7. Press Stop on the HPU front panel to stop the HPU and remove output pressure. Operation 2-3 Remote Operation 1. Turn the Source Remote/Local switch to Remote. Make sure that the remote control cable is connected to the cable connector (the figure on the left shows the location of this connector) and to the remote control device. 2. Apply electrical power. 3. Press Reset (must be pressed whenever electrical power to the HPS has been interrupted). remote control connector 4. Use the remote control device to start the HPU at low pressure. 5. Check for leaks and unusual sounds. VW-G045A 6. Select high pressure at the remote control device. 7. Use the Off switch on the remote control device to stop the HPU and remove output pressure. 2.3 Supercharge Pump Operation When to use the supercharge pump When the temperature of the hydraulic fluid in the HPU reservoir exceeds 140˚F (60˚C), the fluid over-temperature switch automatically shuts down the HPU. The HPU main pumps cannot be restarted in local or remote until the hydraulic fluid cools. Cooling procedure The following procedure uses the supercharge pump to hasten the cooling of the hydraulic fluid: Operation 2-4 1. Ensure the water supply to the heat exchanger is turned on. 2. Press the Start switch without pump motor 1 or 2 selected. The supercharge pump operates independently of the main pumps and circulates hydraulic fluid through the heat exchanger to cool the fluid. 3. When the temperature gage reads approximately 130˚F (54˚C), press the Stop switch to turn off the supercharge pump. 4. To restart the HPU, first press the Reset control on the local or remote control panel to clear the hydraulic interlock circuit, and then start the HPU in low pressure. Section 3 Service This section contains service information for the Model 506.82/.92 Hydraulic Power Unit (HPU). It provides: Introduction • maintenance procedures • service adjustments • electrical information 3.1 Maintenance Procedures Maintenance overview The following sections provide the routine maintenance procedures for the HPU. Figure 3-1 shows the location of the components accessed for the maintenance procedures. Table 3-1 lists the maintenance schedule. high pressure filters supercharge pump/motor pressure accumulator low pressure filter manifold drain heat exchanger filter drain VW-G043E Figure 3-1. Location of Maintenance Components (HPU Side View) Service 3-1 Table 3-1. Maintenance Schedule Procedure Interval Subsection Check output pressure on gage* daily Replace high-pressure filter whenever the indicator points to change 3.1.1 Replace low-pressure filter whenever Dirty Filter indicator lights 3.1.1 Check hydraulic fluid level on gage daily 3.1.2 Check hydraulic fluid in reservoir 150 operating hours 3.1.2 Analyze hydraulic fluid 500 operating hours 3.1.2 Check accumulator precharge at established interval 3.1.3 Check hydraulic hoses monthly * 3.1.1 See Subsection 3.2.1 to adjust the output pressure. Filters Fluid filtration is provided by two 10-micron high-pressure filters (one for each pump), and one 3-micron low-pressure filter. See Figure 3-1 for the location of the filters and their drains. ! WARNING High-pressure release occurs if the system is pressurized. High-pressure release may cause personal injury or damage equipment. Ensure that the output pressure gage reads zero before replacing the filters. 3-2 Service 3.1.1.1 High-Pressure Filter Replacement KO CHA NG E Replace the high-pressure filter elements whenever the DIRT ALARM indicator mounted on the base of each high-pressure filter housing points to CHANGE (red or yellow zone) or whenever the hydraulic fluid is replaced. DIRT ALARM VW-GO46 1. Press Stop on the HPU. The output pressure gage must read zero. End Cap – Top View unscrew to remove endcap 2. Loosen the air-bleed screw on top of the filter housing endcap. With a container under the manifold drain port (Figure 3-1), open the port to drain the fluid for both filters (the pressure accumulator also drains). unscrew to bleed When the fluid is drained, close the drain port and tighten the airbleed screw. Discard the fluid according to company policy. VW-GO47 3. Unscrew and remove the endcap. Remove the compression spring plate on top of the filter elements and remove the filter elements. O-ring and backup ring 4. Remove and save the grommet between the two filter elements. Discard the filter elements. 5. Inspect the O-ring and back-up washer in the end-cap. If replacement is not required, clean and lubricate them with clean hydraulic fluid. spring spring plate 6. Inspect the filter housing for any remaining contamination. filter filter housing 7. Insert two clean filter elements (MTS part number 100533-05), with the grommet between the two elements, into the filter housing. 8. Inspect the compression spring plate and replace the end-cap. Taking care not to damage the O-ring and the back-up washer, tighten the end-cap. VW-GO48 After you have finished Operate the HPU in low pressure for 5 minutes to remove air from the filter housing. Check for leaks while doing this. Service 3-3 3.1.1.2 Low-Pressure Filter Replacement The low-pressure filter element requires replacement whenever hydraulic fluid in the HPU reservoir is replaced, or the Filter Dirty indicator on the HPU front control panel lights.1 See Figure 3-1 for the location of the filter. Refer to the figure on the left to locate the components accessed for the following procedure. bleed screw with O-ring 1. Press Stop on the HPU. The output pressure gage must read zero. 2. Disconnect the cable from the filter manifold. 3. Remove one of the two bleed screws at the top of the filter cover. 4. Place a container under the filter drain and drain the fluid. Dispose of the fluid according to company policy. O-ring O-ring (supplied with filter) 5. Replace and tighten the bleed screw and drain plug. filter filter housing VW-GO49 6. Hand turn the handle counterclockwise until it screws off. Remove the cover. 7. Remove and discard the filter element. Inspect the filter housing for any remaining contamination. 8. Insert a new filter element (MTS part number 114028-17). 9. Hand tighten the cover. Reconnect the cable. After you have finished 3-4 Service Purge the filter housing of air and allow it to fill with fluid as follows: 1. Open the bleed screw 1-1/2 turns. 2. Press the Reset control to reset the Filter Dirty indicator. 3. Jog the supercharge pump motor by pushing the Start button with neither main pump selected, then immediately pushing the Stop button. Continue this procedure until hydraulic fluid appears at the loosened bleed screw. 4. Close and tighten the bleed screw. 3.1.2 Hydraulic Fluid Regular maintenance of hydraulic fluid maximizes the service life of the system and its components. Daily fluid checks Monthly fluid checks Yearly (every 500 operating hours) fluid checks Check the fluid-level in the transparent gage. A low level can indicate a leak. A high level can indicate water contamination from the heat exchanger. If the fluid appears to have changed significantly, obtain a sample from the HPU reservoir and check it for the following qualities: • Considerable darkness, burnt odor, or an opaque quality of the fluid indicates chemical breakdown. It may also indicate that the fluid temperature was too high. Replace the fluid. • During operation, a milky appearance indicates water is present in the fluid. If the system is not in operation, water separates from the hydraulic fluid and settles at the bottom of the reservoir. If water contamination is present, correct the source of the water leakage and replace the hydraulic fluid. Perform these checks monthly or every 150 operating hours (whichever comes first). • Keep records of the maximum reservoir temperature. High operating temperatures can cause the fluid to break down. • Check for contamination and fluid breakdown. Take a fluid sample and test the pH level using a pH kit (available from chemical stores). Also, check the sample for color and odor. • Take a fluid sample and let it stand overnight. Sediment at the bottom of the fluid indicates collapsed, ruptured or clogged filters. Obtain a sample of the fluid and have it analyzed. The fluid tests should include chemical analysis, particle count, and viscosity checks. Record the results and replace the fluid if necessary. Service 3-5 Replacing hydraulic fluid HPS – Rear View Perform this procedure to replace the hydraulic fluid. You will need a Model 590.01 Fluid Transfer Pump or a pump which provides at least 10-micron filtration. 1. Turn off electrical power to the HPU. Remove the reservoir filler cap assembly. 2. Drain the hydraulic fluid into a container, while hot, through the drain valve. Close the valve. drain Then drain the oil from the entire system (such as from the hoses and accumulators). Dispose of the fluid according to company policy. VW-G042D 3. Remove the top plate from the reservoir. 4. Wipe the inside of the reservoir with a clean lint-free cloth. Apply MOBILSOL A—a solvent for cleaning and flushing hydraulic systems—to a clean lint-free cloth and again wipe the reservoir. Immediately wipe away the solvent with a dry cloth. 5. Replace the high-pressure filter element. See Subsection 3.1.1.1. 6. Replace the low-pressure filter element. See Subsection 3.1.1.2. ! CAUTION To avoid damage to the hydraulic system, follow these precautions: Do not mix different brands of hydraulic fluid. This can create contaminants. Ensure that the replacement hydraulic fluid is the same brand and type as the fluid which was removed. Generally, an MTS Hydraulic Power Unit contains Mobil DTE 25 hydraulic fluid. Consult MTS before you use alternate fluids. Use a transfer pump that provides 10-micron or better filtration. Most commercial hydraulic fluids exceed the maximum amount of contamination allowable in MTS hydraulic systems. 3-6 Service 7. Use the transfer pump to fill the reservoir with fresh hydraulic fluid. 8. To flush out the pipe line, connect a hose from the pressure line to the return line of the last station, and operate the HPU at low pressure for 2 - 4 hours. 9. Replace the high-pressure filter if necessary (Subsection 3.1.1.1). 3.1.3 Accumulators For more information about accumulators See the Series 111 Accumulator product manual (MTS part number 115533XX). For other accumulators, refer to the vendor literature or the Procedure for Checking Piston and Bladder Type Accumulator Precharge and Precharging (MTS part number 408266-XX). pressure accumulator pressure gage filter drain back-up relief valve slow turn-on accumulator Figure 3-2. Location of Accumulators 3.1.3.1 Pressure Accumulator Precharge Pressure-Checking Intervals Precharge pressure of the pressure accumulator (Figure 3-2) must be checked at regular intervals. To establish an interval time, follow this procedure: 1. Initially, check the precharge pressure after 2 weeks or 100 operating hours. 2. If the pressure changes more than 200 psi, check the precharge pressure every week or 50 operating hours. If the pressure changes less than 200 psi, check the precharge pressure every four weeks or 200 operating hours. Service 3-7 Precharge pressure of the slow turn-on accumulator (Figure 3-2) must be checked at regular intervals. To establish an interval time, follow this procedure: Slow Turn-on Accumulator 1. Initially, check the precharge pressure after 2 weeks or 100 operating hours. 2. If there is a pressure-level change of more than 50%, check the precharge pressure every week or 50 operating hours. If there is a pressure-level change of less than 50%, check the precharge pressure every four weeks or 200 operating hours. 3.1.3.2 Precharging the Accumulators If the pressure accumulator has a pressure-level change of ±200 psi between checks, recharge it. If the slow turn-on accumulator has a pressure-level change of ±50% between checks, recharge it. The pressure and slow turn-on accumulators are typically precharged to 1000 psi (7 MPa) and 800 psi (5.5 MPa), respectively. These are the recommended levels for an HPU output pressure of 3000 psi (21 MPa). 3.1.3.3 Changing the Accumulator Seals When you have established a regular interval for checking the precharge pressure, note the amount of pressure loss that occurs each time the precharge pressure is checked. If an increase in pressure loss occurs during the period between checks, the seals may require replacement. 3-8 Service 3.2 Service Adjustments Service overview Figure 3-3 shows the location of the service components accessed for the following procedures. • • • • output pressure adjustment dual-temperature switch adjustments low-level switch adjustment main pump low-inlet pressure switch adjustment pressure control - pump no. 1 pressure control - pump no. 2 low-level switch dual-temperature switch adjustment back-up relief valve low-inlet presssure switch VW-G043G Figure 3-3. Location of Adjustment Components (HPU Side View) Service 3-9 3.2.1 Output Pressure Adjustment Refer to Figure 3-2 for the location of the components indicated in the following procedure. 1. Turn off the HPU. 2. Make sure that the output pressure gage reads zero (Figure 3-2 shows the location of the pressure gage). 3. Remove the plastic cap on both pump pressure controls. Loosen the locknuts and turn both pressure controls fully counterclockwise. 4. Loosen the locknut on the back-up relief valve and turn the adjustment knob fully counterclockwise. locknut adjustment knob VW-G050 5. Press Pump 1 Select on the HPU Control Panel. 6. Press Start to run the HPU at low pressure, then press High Pressure. 7. Observe the pressure gage and alternately turn the back-up relief valve adjustment and the pressure control on pump 1 clockwise (Adjustment increments should be approximately 500 psi (3.45 MPa) apart as indicated on the pressure gage.). Stop adjusting at approximately 500 psi (3.45 MPa) above the desired output pressure (typically 3000 psi/21 MPa). 3-10 Service 8. Tighten the locknut on the back-up relief valve. 9. Turn the pressure control on pump 1 counterclockwise until the desired output pressure is reached. 10. Turn off the HPU. 11. Press Pump 2 Select on the HPU Control Panel. 12. Press Start to run the HPU at low pressure, then press High Pressure. 13. Turn the pressure control on pump 2 clockwise until output pressure on the pressure gage reads approximately 100 psi (0.5 MPa) lower than the pressure control 1 setting. NOTE After you have finished A differential pressure between the pressure setting of pump 1 and pump 2 prevents crosstalk between the two hydraulic circuits Replace the plastic caps removed in step 3. Whenever the output pressure is changed, the accumulator precharge must also be checked (see Subsection 3.1.3). Service 3-11 3.2.2 Dual-Temperature Switch Adjustments The dual-temperature switch has two adjustment screws behind its front protective cover. The Over Temperature adjustment turns off the HPU if hydraulic fluid reaches a temperature of 140˚F (60˚C). Definition The Water Solenoid Control adjustment allows water flow to the heat exchanger when an oil temperature of 105°F (40°C) is exceeded. The water solenoid control is only used if the optional water solenoid valve is required. ! WARNING Do not touch the dual temperature switch’s electrical leads. They carry 120 Vac. Touching them could give you a serious or even fatal shock. Perform this procedure wearing insulated gloves and using an insulated screwdriver. HPS – Rear View Dual Temperature Switch – cover removed adjustment screws temperature gage DO NOT TOUCH! (read the Warning) VW-G042E Before you begin Turn off the HPU. Loosen the screws on each side of the switch assembly, and pull the front protective cover off. The adjustment screws are labeled. Over-temperature adjustment 1. Turn the over-temperature adjustment screw (figure above) several turns clockwise to raise the temperature limit. 2. Turn off the water supply to disable the heat exchanger. 3. Turn on the HPU and apply high pressure (see Subsection 2.2). 4. When hydraulic fluid temperature reaches 140˚F (60˚C), as indicated on the temperature gage, turn the adjusting screw counterclockwise until the HPU turns off. 5. Turn on the cooling water supply. 3-12 Service 1. Start this procedure when the temperature gage shows that the hydraulic fluid is below 90°F (32°C). Water control adjustment 2. Start the HPU. 3. Make sure the square shaft on top of the water regulating valve is turned fully counterclockwise to shut off water flow. 4. Monitor the temperature gage as the hydraulic fluid heats up. 5. When the fluid temperature reaches approximately 120°F (49°C), turn the adjustment screw clockwise until water starts to flow. Then turn this screw counterclockwise until water flow stops. 6. If the fluid temperature does not reach 125°F (52°C) turn the screw a half-turn counterclockwise and note the effect after 15 minutes. If the temperature exceeds 125°F (52°C), turn the screw clockwise. 7. After adjustments are completed, turn the square shaft on top of the water regulating valve fully clockwise for full cooling water flow. 3.2.3 Low-Level Switch Adjustment The low fluid-level switch turns off the HPU if there is an appreciable loss of hydraulic fluid. The factory-adjustment coincides with the bottom of the fluid level gage and does not normally require readjustment. Perform the following steps if readjustment is necessary. 1. With the HPU turned off, fill the reservoir to the correct fluid level. locknut top of reservoir 2. Turn on the HPU and apply high pressure. VW-G051 3. See the figure on the left. Loosen the hand locknut on the stem of the switch, and slowly raise the switch until the Low Fluid Level indicator lights. 4. Lower the switch about 1.5 in. (38 mm). 5. Tighten the locknut. 6. Reset any applicable interlock circuits. Service 3-13 3.2.4 Main Pump Low-Inlet Pressure Switch Adjustment The main pump low-inlet-pressure switch shown in the figure below monitors the pressure level supplied by the supercharge pump at the input to the main pumps. The switch protects the main pumps by turning off the HPU if the supercharge pump pressure drops below the minimum level required by the main pumps. Pressure Switch – Cover Off adjustment knob VW-G052 The switch is set at the factory to activate at 30 psi (0.21 MPa). This switch may be adjusted with or without the HPU running. When to adjust the switch Figure 3-3 shows the location of the switch on the HPU. Check the position of the pressure setting indicator on the switch (see the figure above and left). It should be set at 30 psi (0.21 MPa). If it is not, follow the procedure below to adjust the switch. How to adjust the switch Turn the adjustment knob located on top of the switch either clockwise to increase the pressure setting or counterclockwise to decrease the pressure setting to 30 psi (0.21 MPa). 3-14 Service 3.3 Starter Assembly The starter assembly is located behind the starter box door. Figure 3-4 shows the location of the starter assembly components. ! WARNING High voltage is present in the starter assembly. Do not open the starter box door when power is applied to the HPU. Touching components with high voltage can cause death. Remove electrical power at the power disconnect switch before you open the front starter box door. Control Relays Transformer PLC Fuses Motor Relays Figure 3-4 Models 506.82/.92 Starter Assembly (Typical) Service 3-15 3.3.1 Abnormal HPU Shutdown Motor overload Sudden shutdown of the HPU may be due to circuit protection elements in the pump motor starter assembly. If the supercharge motor overloads, the relay opens and de-energizes the motor starter coils to shut down the HPU. If either pump 1 or pump 2 motor overloads, the associated pump shuts down. Reset procedure If a motor overloads, follow this procedure to reset it. 1. Turn off ac power at the HPU disconnect switch. ! WARNING High voltage is present in the starter assembly if power is not removed. Failure to remove power before opening the HPU starter box door may cause death or injury. Remove electrical power at the power disconnect switch. 2. Open the starter box door and locate the appropriate motor overload relay (see Figure 3-4). 3. Press the reset button located on the relay to enable operation. NOTE 3.3.2 The overload relay element may be equipped with a switch to provide manual or automatic reset. This switch should always be set to the manual position. Fuse Replacement Table 3-2 lists the fuse values and part numbers of the fuses located in the 506.82 and 506.92 standard 460 Vac, three-phase starter assemblies. Figure 3-4 shows the location of the fuses. Table 3-2. Starter Assembly Fuse Values Fuses Type FU 1 through FU 3 FU 4 and FU 5 FU 6 FU 7 FU 8 through FU 13 3-16 Service 506.82 HPU MTS PN 45A slo-blo 3A slo-blo 6A slo-blo 4A slo-blo 250A slo-blo 100725-15 111457-06 100524-27 100524-04 100725-52 Type 506.92 HPU MTS PN 70A slo-blo 3A slo-blo 6A slo-blo 4A slo-blo 350A slo-blo 100725-37 111457-06 100524-27 100524-04 100725-61 3.3.3 PLC Service The programmable logic controller (PLC) in the 506.82/.92 HPU starter assembly has a fixed controller with both output and input indicators. These indicators are described in Tables 3-3 and 3-4. Optional modules with additional output indicators can be added for remote control of your HPU. These additional output indicators are described in Table 3-5. Fixed Controller Output Terminals Remote Control Modules (Option) Output Status LEDs Processor Status LEDs Input Terminals Input Status LEDs Figure 3-5. Fixed Controller with Remote Control Modules Service 3-17 Table 3-3. Fixed Controller Output Indicators Output Indicator Ch0 Description 0 Turns on to energize pump motor 1 start control relay CR1. 1 Turns on to energize pump motor 1 run control relay CR2. 2 Turns on to energize pump motor 2 start control relay CR3. 3 Turns on to energize pump motor 2 run control relay CR4. 4 Turns on to energize pump motor 1 high- pressure solenoid SOL1. 5 Turns on to energize pump motor 2 high- pressure solenoid SOL2. 6 Turns on to energize main high- pressure solenoid SOL3. 7 Turns on to energize water inlet solenoid SOL4 that allows water flow into the heat exchanger for cooling hydraulic fluid. 8 Turns on to light front panel Over Temperature indicator. 9 Turns on to light front panel Low Oil Level indicator. 10 Turns on to light front panel Overload indicator. 11 Turns on to light front panel Dirty Filter indicator. 12 Turns on to light indicator on Pump 1 Select switch. 13 Turns on to light indicator on Pump 2 Select switch. 14 Turns on to light indicator on Local Mode switch. 15 Turns on to energize supercharge pump control relay CR5. Table 3-4 Fixed Controller Input Indicators Input Indicator Ch0 3-18 Description 0 Spare 1 Spare 2 Turns on momentarily if the Start switch is pressed. 3 Turns on momentarily when Stop switch is pressed. This momentary “high” will shut off the pump it is running. 4 Turns on momentarily if the High Pressure switch is pressed 5 Turns on momentarily if the Local Mode switch is pressed. 6 Turns on momentarily if the Pump 1 Select switch is pressed. 7 Turns on momentarily if the Pump 2 Select switch is pressed. 8 Turns on if the front panel Reset switch is pressed. 9 Turns off if the E-Stop chain through the remote connector is not satisfied. 10 Spare Service Table 3-4 Fixed Controller Input Indicators (Continued) Input Indicator Ch0 Description 11 Spare 12 Turns off if motor overload relay contact OL1, OL3, or OL5 opens indicating that the respective pump motor 1, pump motor 2, or the supercharge pump has tripped its respective overload. This event indicates excessive current draws. 13 Turns on if motor relay M5 closes to show the supercharge pump is running. 14 Turns on if motor relay M2 closes to indicate pump motor 1 is running. 15 Turns on if motor relay M4 closes to indicate pump motor 2 is running. 16 Turns on if remote start is initiated. 17 Turns on if remote run is initiated. 18 Turns on if remote high pressure is initiated. 19 Turns off if switch FS1 opens to indicate that the fluid level has dropped below a preset limit. 20 Turns on if inlet pressure switch PS1 (30 psi) closes prior to start up of the main pump(s). Inlet pressure is supplied by the supercharge pump. 21 Turns off if ∆P switch PS2 opens to indicate the fine filter is dirty. 22 Turns off if switch TAS1 (140°F) opens to indicate that the hydraulic fluid temperature has exceeded a preset limit. 23 Turns off if switch TAS2 (100°F) opens. When fluid temperature exceeds a preset limit, TAS2 opens to energize water inlet solenoid SOL4. SOL4 opens the optional water regulation valve, letting water into the heat exchanger. Table 3-5. Remote Control Module Output Indicators Output Indicator Ch1 Description 100 Remote low-level interlock/indication. 101 Remote over-temperature interlock/indication. 102 Remote dirty filter interlock/indication. 108 Turns on to energize RCR control relay. Opening the RCR control relay cuts off 24 Vdc to the remote connector. 109 Remote run indication. Service 3-19 Section 4 Installation Introduction This section provides the following installation information for the Model 506.82/.92 Hydraulic Power Unit (HPU). • • • Before you complete connections hydraulic connections electrical connections water connections Perform these steps before you make any connections to the HPU. 1. Remove the shipping plate located under the hydraulic fluid filler cap. 2. Make sure that the chained jumper plug is connected to the remote control connector located on the side of the starter box door. See the figure below. starter box door remote control connector VW-G045B Figure 4-1. Location of Remote Control Connector For remote control connection The jumper plug may be replaced by the system cable from a remote control device when the HPU is ready for system operation. Installation 4-1 4.1 Hydraulic Connections The pressure, return and drain connections are located on the HPU manifold shown in Figure 4-2. Refer to the system hydraulic distribution drawing in the system Reference Manual for hydraulic connections that are specific to your system. Hydraulic hose connections from the HPU are made to the ports labeled P (pressure) and R (return) on the HPU manifold. These connections are typically made to a system servovalve manifold, hydraulic service manifold, or hydraulic distribution manifold. The HPU has drain ports for any drainback connections used by the system. Hydraulic connections HPS – Rear View drain ports pressure ports return ports VWG044J Figure 4-2. Hydraulic Connections NOTE Installation 4-2 Table 1-2 shows the specifications for the ports shown in Figure 4-2. 4.2 Electrical Connections The HPU is operated from a three-phase electrical power source. Operating voltage is labeled on the starter assembly and pump motor. Electrical connections must be made by qualified personnel and conform to local codes and regulations. Before you begin Install a fused power disconnect switch (customer supplied) following local codes. This switch removes electrical power to the HPU. ! WARNING When the electrical connections have been made, high voltage is present in the starter assembly when power is on. Do not open the starter box door with power applied to the HPU. Touching components with high voltage can cause death. Remove electrical power at the power disconnect switch before you open the front starter box door. Control Relays Transformer PLC Fuses Motor Relays Figure 4-3. Models 506.82/.92 Starter Assembly (Typical) Installation 4-3 4.2.1 Transformer Wiring One of two types of transformers is installed in the starter assembly. Check the wiring configuration of the transformer before applying ac power to the HPU. Standard transformer wiring Figure 4-4 shows the jumper wiring required on a standard transformer for source voltages of 460. 460 Vac H1 H3 H2 H4 X2 X1 VW-C036 Figure 4-4. Standard Transformer Wiring Configuration An optional multi-tap transformer may be used for source voltages other than 230 Vac and 460 Vac. The following figure shows the typical wiring required for various voltages. Source voltages are applied to terminals H1 through H5 as shown. An output voltage is tapped from terminals X1 through X4. Check the output voltage with a voltmeter. It should be 110 Vac for systems using 50 Hz power and 115 to 120 Vac for systems with 60 Hz. Optional transformer wiring H1 H2 H3 H4 H5 208/220/230/240 Vac 380/400/416 Vac 440/460/480 Vac 500/550/575/600 Vac 110/120/125/130 Vac jumper 100/110/115/120 Vac 85/91/99 Vac X4 X3 X2 X1 VW-C037 Figure 4-5. Typical Multi-Tap Transformer Wiring Configuration Installation 4-4 4.2.2 Electrical connection procedure Polarity check Input Power See Figure 4-3 and perform the following procedure to make the electrical connections. 1. Connect a solid earth ground from the power disconnect switch to the starter assembly. 2. Connect the three input leads from the disconnect switch to the three terminals located on the starter assembly. Perform this procedure to ensure that electrical power is properly connected to the HPU: 1. Apply ac power to the HPU. The Power On indicator should light. 2. Jog the supercharge pump motor by pushing the Start button with neither main pump selected, then immediately pushing the Stop button. ! WARNING High voltage is present in the starter box if power is not removed. Failure to remove power from the box may cause death or injury. Remove electrical power at the power disconnect switch. 3. If the supercharge motor is rotating in the direction indicated by the arrow on the pump motor housing, electrical connections are correct. If it is rotating in the opposite direction of the arrow, remove ac power to the HPU and switch two of the three input power leads to the HPU (refer to Figure 4-3). Installation 4-5 4.3 Cooling Water Connections Specifications The differential pressure required between the water inlet and outlet connections is 30 to 45 psid (0.2 to 0.3 MPa). The maximum allowable water pressure is 120 psi (0.83 MPa). The water supply must be capable of providing water flow at a rate indicated in Table 1-1. See Table 1-2 for the maximum cooling water heat load. Water connections To connect the water supply and drain to the heat exchanger water connections , use a 1.5 in. (38 mm) water service hose for the 506.82 HPU. Use a 2 in. (50.8 mm) water service hose for the 506.92 HPU. Heat Exchanger – Top View water out hot fluid - from supercharge pump cold fluid - to low pressure filter Installation 4-6 water regulating valve VW-G055 water in Section 5 Theory of Operation This section describes the hydraulic and electrical operation of Model 506.82/.92 Hydraulic Power Unit (HPU). 5.1 Hydraulic Operation The figure below is a block diagram of the HPU hydraulic operation. pressure -24 JIC pressure -32 4 bolt pressure accumulator return return -24 JIC -32 4 bolt pressure gage outlet filter 10 micron outlet filter 10 micron check valve 3Sol 24 Vdc check valve backup relief valve 3500 psi (25 MPa) main manifold assembly slow turn-on accumulator pump 1 – compensator set at 3000 psi (21 MPa) 1Sol 2Sol pump 2 – compensator set at 3050 psi (21 MPa) low inlet pressure switch 20 psi (0.14 MPa) 1PS optional water shut-off solenoid valve 24 Vdc 4Sol water in filter pressure switch 35 psi (0.24 MPa) 2PS standard water regulating valve filter bypass 50 psi (0.34 MPa) supercharge relief valve – cracks at 30 psi (0.2 MPa) 3 micron fine filter supercharge and manifold filter heat exchanger water out water shut-off solenoid valve switch – 100°F (38°C) rising supercharge pump fluid level/temperature gage over-temperature switch – 140°F (60°C) rising low fluid level float switch 1FS VW-C038 Figure 5-1. Hydraulic Block Diagram Theory of Operation 5-1 Main and supercharge pumps The HPU uses two variable-volume pressure compensated main pumps, with a pressurized (supercharged) hydraulic fluid inlet to provide fluid flow. The supercharge pump draws hydraulic fluid from the reservoir and forces it through a heat exchanger and a low-pressure filter. Fluid not required by the main pumps returns to the reservoir through check valves in the low-pressure filter manifold. The supercharge pump is mounted vertically inside the reservoir. Filters Hydraulic fluid from the low-pressure filter is routed to the main pumps. A low-inlet pressure switch monitors the inlet pressure (supercharge output pressure) to the main pumps. Fluid from the main pumps outlet passes through a check valve and a 10micron high-pressure filter. The output pressure is controlled by the pressure compensator adjustment on the main pumps and is monitored by the output pressure gage. Output volume varies automatically with external circuit demand. Back-up relief valve An adjustable back-up relief valve limits output pressure by porting fluid back to the reservoir. When the pump compensators are operating normally, the relief valve does not open. High/low solenoid valves High/low pressure operation is controlled by the high/low solenoid valves. These valves control the main pressure control (pressure compensator) vent ports and the backup relief valve vent port. With the high/low solenoid valves de-energized, the main pressure control vent ports and the back-up relief valve vent port are open and output volume is ported to the reservoir, limiting output pressure to approximately 150 psi (1.03 MPa). This low-pressure condition occurs during supply turn-on for low pressure start-up and during power-up of the HPU. With the high/low solenoid valve energized, the vent ports are blocked and system pressure can rise to the preset operating pressure, typically 3000 psi (21 MPa). Fluid temperature Hydraulic fluid temperature is maintained at a recommended operating level by a fluid-to-water heat exchanger which passes the fluid over waterfilled tubes. Water flow through the tubes is automatically regulated by a water regulating valve. If fluid temperature exceeds a preset limit (typically 140°F), a temperature-sensitive switch turns the HPU off. Pump protection Pump protection is provided for the main pumps by the main pump lowinlet pressure switch that turns the supply off if supercharge pressure drops below the recommended operating pressure. The supercharge pump and main pumps are protected by a fluid-level switch which turns the supply off if the level of hydraulic fluid in the reservoir drops below a preset level. Theory of Operation 5-2 Pressure accumulation The pump-outlet pressure accumulator smoothes the HPU output and provides additional hydraulic pressure for high instantaneous flow demands. It is precharged with dry nitrogen to a pressure proportional to HPU output pressure. The optional slow turn-on accumulator slows the rate at which the backup relief valve shifts from low to high pressure. The precharge must be adjusted proportionally to the HPU output pressure. If it is above or below the recommended level, the effect of the accumulator is reduced. 24 Vdc operation The HPU includes a 24 Vdc electrical power supply for operating solenoid valves, relays and the PLC. Current available for external use is listed in the specifications table. All solenoid valves connected to this supply must be rated at 24 Vdc. If the 115 Vac control voltage option is required, all solenoid valves connected to the supply must also be rated at 115 Vac. 5.2 Electrical Operation This section provides the HPU electrical theory of the operation. Figure 52 is a typical electrical schematic for the 506.82B/.92B HPU. HPU operation is controlled by a PLC (programmable logic controller). It is designed so that a desired circuit in relay ladder logic can be programmed. The PLC provides logic functions previously accomplished by relays, timers and sequencers. It contains an I/O section that receives input data from various switches and contacts that are hardwired to the input terminals. The PLC sends output commands to motors, motor starters, solenoid valves and indicator lights that are hardwired to the output terminals. The PLC operating program is retained by an EPROM memory module. A back-up battery is not required. Theory of Operation 5-3 5.2.1 Control When the disconnect switch is closed, the HPU control panel Power On indicator lights to show that electrical power to the HPU is on. Inlet pressure Pressing Start with Pump 1 Select , Pump 2 Select , or both pumps selected energizes relay CR5 at PLC output 15 to start the supercharge motor. Contacts M5 provide the supercharge motor status to PLC input 13. The supercharge motor provides inlet pressure for pumps 1 and 2. When the inlet pressure is reached (typically 30 psi), pressure switch 1PS (connected from the outlet of the supercharge pump to PLC input 20) closes which allows the PLC to start the pump motor(s). Supercharge only operation Pressing Start without Pump 1 Select or Pump 2 Select selected energizes relay CR5 at PLC output 15 to start the supercharge pump motor. Contacts M5 provide the supercharge pump motor status to PLC input 13. The supercharge pump provides inlet pressure for pumps 1 and 2. Supercharge pump only operation is typically used to hasten hydraulic fluid cooling after a fluid over-temperature shutdown of the HPU. Refer to Subsection 2.3 for a fluid cooling procedure using the supercharge pump. Start control The start signal is sent to input 2 of the PLC. If various conditions (such as interlocks) are satisfied, a pump unit start up is initiated. Depending on which pump is selected, PLC output 0 energizes pump motor 1 start control relay (CR1) or PLC output 2 energizes pump motor 2 start control relay (CR3). Pump motor 1 When CR1 contacts close, pump motor 1 starts, using a Wye-delta start. First relay S1 energizes to close S1 contacts and energize relay M1 (M1 contacts close). Relays M1 and S1 provide a Wye connection (this reduces inrush current) to start pump motor 1. After a timing delay that the PLC provides, PLC output 1 energizes relay CR2. The state of all CR2 contacts change to de-energize S1 and energize M2. Relays M1 and M2 connect the motor windings in a delta configuration to provide full current to the motor. A set of M2 contacts provides the motor 1 status to the PLC at input 14. Pump motor 2 If pump motor 2 is selected, PLC output 2 energizes relay CR3. Pump motor 2 uses a Wye-delta start configuration. Relays M3 and S2 provide the start connection to the motor. Relays M3 and M4 provide the run connection. A set of M4 contacts provides the motor 2 status to the PLC at input 15. High pressure When the HPU High Pressure switch is pressed with a pump unit activated, high pressure is enabled by energizing high-pressure solenoid SOL1 for pump 1, SOL2 for pump 2, and SOL3 for the HPU. Theory of Operation 5-4 When the stop switch at PLC input 3 is pressed, the two pump motors are shut down after a one second delay. The supercharge pump motor, however, continues to run for approximately five seconds. Stop control Pressing Emergency Stop turns off the HPU by de-energizing relay CRM. CRM contacts open to cut off power to the motor starters. The supercharge pump may continue to run briefly while the main pumps wind down. 5.2.2 Interlocks The HPU contains interlock circuitry to shut down the HPU when various conditions occur—such as low level hydraulic fluid, overtemperature, low pressure, dirty filters and motor overload. Reset When the interlock condition has been corrected and the HPU is restarted, the Reset switch at PLC input 8 must be pressed to reset the interlock circuitry. Low-level hydraulic fluid Low fluid level switch FS1 protects the HPU if there is an appreciable loss of hydraulic fluid. Whenever the level of hydraulic fluid in the HPU reservoir drops below a preset limit, switch FS1 (at PLC input 19) opens to turn off all pump motors, and disable the supercharge pump. PLC output 100 will go low to signal the low fluid fault through the remote connector. PLC output 9 lights the Low Oil Level indicator on the HPU front panel. Fluid overtemperature condition Whenever the temperature of the hydraulic fluid in the HPU reservoir exceeds a preset limit, switch TAS1 (at PLC input 22) opens to turn off the HPU pump motors. PLC output 101 will go low to signal the overtemperature fault through the remote connector. PLC output 8 lights the Fluid Over-Temperature indicator on the HPU front panel. The supercharge pump can be operated to cool the fluid. Refer Subsection 2.3 for a fluid cooling procedure. Low-inlet pressure Pressure switch PS1 protects the main pumps if inlet pressure drops below the minimum level required by the main pumps. Switch PS1 (at PLC input 20) closes whenever low-inlet pressure drops below a preset limit (typically 30 psi). Opening PS1 while the pump motor is operating, turns off the HPU. Optional water shut-off solenoid valve On units equipped with this valve, switch TAS2 (at PLC input 23) opens to energize the water-inlet solenoid SOL4 (at PLC output 7) whenever the hydraulic fluid exceeds a preset temperature limit. This solenoid opens the water shut-off valve, letting water flow through the heat exchanger to cool the hydraulic fluid. Dirty filter The low-pressure fine filter is monitored by ∆P switch PS2 (at PLC input 21). When a dirty filter creates excessive differential pressure across the filter, switch PS2 opens. PLC output 102 generates the dirty filter warning through the remote connector. PLC output 11 lights the Dirty Filter indicator on the HPU front panel. If the indicator is active when the HPU shuts down, Reset must be pressed (after the filter is replaced) to restart the HPU. Theory of Operation 5-5 Motor overload Thermal overload sensors detect excessive current and open the normally closed contacts connected to the motor starter coil. Motor overload relay contacts OL1, OL3, or OL5, all at PLC input 12, open to turn off the HPU if the respective pump motor 1, pump motor 2, or supercharge pump motor is drawing excessive current. The LED lights from PLC output 10 When an overload condition occurs, the reset button on the motor overload relay must be pressed (see Subsection 3.3.1). NOTE Hydraulic power supplies are often customized for specific applications. Actual wiring may differ from what is shown in Figure 5-2. You will find the wiring schematic for your system in the product information kit inside the starter box and in the Assembly Drawings manuals specific to your system. Theory of Operation 5-6 Figure 5-2. Typical Electrical Schematic Theory of Operation 5-7 Figure 5-2. Typical Electrical Schematic (Continued) Theory of Operation 5-8 Figure 5-2. Typical Electrical Schematic (Continued) Theory of Operation 5-9 Figure 5-2. Typical Electrical Schematic (Continued) Theory of Operation 5-10 Index abnormal shutdown 3-16 accumulators functional description 1-2 location 3-7 maintenance 3-7 seals 3-8 theory of operation 5-3 adjustments location of components 3-7 low fluid level 3-12 low-inlet pressure 3-14 output pressure 3-10 temperature 3-12 water control 3-13 component location front panel controls 2-1 maintenance 3-1 service 3-9 connections electrical 4-3 hydraulic 4-2 specifications 1-3 water 4-6 controls 1-1, 2-1, 2-2 electrical connection procedure 4-5 connections 4-3 fuses 3-15 installation 4-3 motor overload 3-15 schematic 5-7 specifications 1-3 starter assembly 3-14 theory of operation 5-3 wiring transformer 4-4 emergency stop switch 2-1, 2-2 filters indicators 2-1, 2-2, 3-2 interlock 5-5 maintenance 3-2 specifications 1-3 theory of operation 5-2 fluid level adjustment 3-13 functional description 1-2 gage 1-2, 2-1, 2-2 indicator 2-1, 2 interlock 5-4 front panel controls 1-1, 2-1, 2-2 fuses location 3-15 replacement 3-16 gages fluid level 2-1, 2-2, 3-13 temperature 2-1, 2-2, 3-12 start switch 2-1, 2-2 hydraulic fluid cooling procedure 2-5 fluid level gage 2-2 low level switch adjustment 3-13 low oil level indicator 2-2 maintenance 3-5 port connections 4-2 specifications 1-3 hydraulic operation 5-2 indicators 1-1, 2-1, 2-2 installation electrical connections 4-3 hydraulic connections 4-2 remote control 4-1 water connections 4-5 interlocks 2-2, 5-5 local HPU operation 2-3 low-inlet pressure 3-14, 5-3 maintenance procedures accumulators 3-6 filters 3-2 hydraulic fluid 3-4 location of components 3-1 maintenance schedule 3-2 meters, hours of operation 2-1, 2-2 motors motor overload 3-16, 5-6 specifications 1-3 theory of operation 5-3 noise rating 1-2 operation remote 2-4, 4-1 pressure accumulator 1-2, 3-7 adjustment 3-8 functional description 1-1 low-inlet pressure interlock 5-5 low-inlet pressure adjustment 3-14 specifications 1-3 theory of operation 5-2 programmable logic controller functional description 1-2 I/O indicators 3-18 theory of operation 5-3 pump 1 select switch 2-1, 2-2 pump 2 select switch 2-1, 2-2 remote control installation 4-1 operation procedure 2-5 reset interlock 5-4 switch 2-1, 2-2 Index-1 schematic electrical 5-6 hydraulic 5-1 service adjustments location of components 3-9 low-inlet pressure 3-14 output pressure 3-10 water control 3-13 local mode switch 2-1, 2-2 specifications 1-3 starter assembly fuses 3-16 installation 4-3 location of components 3-15 motor overload 3-16 programmable logic controller 3-17 specifications 1-2 stop switch 2-1, 2-2 supercharge pump operation procedure 2-4 specifications 1-3 theory of operation 5-2 temperature adjustment 3-12 control 1-2, 2-1, 2-2 fluid cooling procedure 2-5 interlock 5-5 specifications 1-3 theory of operation 5-2 transformer wiring 4-4 water connections 4-5 control adjustment 3-12 control theory 5-5 cooling requirements 1-3 flow 1-3 specifications 1-3 temperature 1-3 wiring transformer 4-4 Index-2