Hubbell Industrial Controls, Inc.
A subsidiary of Hubbell Incorporated
50 Edwards St.
Madison, OH 44057
Telephone (440) 428-1161
FAX (440) 428-7635
Instruction Manual
Transfer Switches
LX-340 Non-Automatic
LX-350 Automatic
150, 260, 400 Ampere
2, 3, 4 Pole
Publication No. 195
February, 1999
Transfer Switch
Table of Contents
1.0 Introduction ............................................................................................................................. 3
2.0 Specifications and Certifications ............................................................................................. 4
Specifications................................................................................................................................. 4
Certifications ................................................................................................................................. 4
3.0 Installation ............................................................................................................................... 4
Receiving and Storage ................................................................................................................... 5
Location ........................................................................................................................................ 5
Line Connections ........................................................................................................................... 5
4.0 Operation ................................................................................................................................. 6
Automatic Operation ..................................................................................................................... 6
5.0 Standard and Optional Features............................................................................................. 7
Standard Features .......................................................................................................................... 7
Optional Features........................................................................................................................... 9
6.0 Maintenance........................................................................................................................... 11
Transfer Test ............................................................................................................................... 11
Troubleshooting........................................................................................................................... 13
Settings ....................................................................................................................................... 13
Component Replacement ............................................................................................................. 15
7.0 Transfer Control Relay Board............................................................................................... 19
8.0 Spare Parts and Drawing References.................................................................................... 21
Spare Parts .................................................................................................................................. 21
Drawing References..................................................................................................................... 22
Page 2 of 22 Pages
Transfer Switch
1.0 Introduction
Hubbell’s Non-Automatic, LX-340, and Automatic, LX-350, Transfer Switches are available in 2, 3, and
4 pole models for 150, 260, and 400 A. The Transfer Switches are available as stand-alone units, Open
Type or in an individual cabinet, or built into an adjoining enclosure for combination Automatic Transfer
Switch/Fire Pump Controller applications.
The Automatic Transfer Switch has a Solid State Transfer Control Module, LX-301, that monitors
voltage and controls the transfer to and from the normal and emergency sources. The Non-Automatic
Transfer Switch has a selector switch to manually initiate transfer. A gear motor powered by
transformers connected to the normal and emergency sources operates the switching mechanism of the
Transfer Switch. A handle is included with all Transfer Switches to manually operate the switch.
TSE
Emergency
Source
Isolation
Switches
Normal
Source
TSN
To load
PRM
optional
Normal Source
Transformer
Control
Module
(LX-301)
Emergency Source
Transformer
Transfer Control
Relay Board
Gear Motor
LX-320 Power Panel
To engine
start contacts
(If generator backup)
Figure 1-1 Block Diagram of Transfer Switch showing one phase
Page 3 of 22 Pages
Transfer Switch
2.0 Specifications and Certifications
Specifications
Gear Motor
90 VDC permanent magnet motor
Pick-up Voltage
90% of normal source voltage
90% of emergency source voltage
Drop-out Voltage
84% of normal source voltage
84% of emergency source voltage
Auxiliary Contacts
10 A, 600 V
Overall dimensions,
Height: 24”, Depth: 11.55,
LX-320 Power Panel
Width: 2 and 3 pole 17”, 4 pole 20.5”
Note
Time delay settings and voltage pick-up and drop-out levels are set at the factory and should not be
changed without consulting the factory.
Certifications
Hubbell’s Transfer Switches meet the requirements for all of the certifications listed below.
UL 1008 Standard for Safety for Transfer Switches
NEC Article 517, Health Care facilities
CSA (Canadian Standards Association)
NEC Article 701, Legally Required Standby
Systems (LX-350 only)
Factory Mutual
NFPA 99 Health Care Facilities (LX-350 only)
NEC Article 702, Optional Standby Systems
NFPA 20
3.0 Installation
Refer to the Transfer Switch nameplate to ensure that the voltage, current, and horsepower ratings are
compatible with the load.
Refer to the receiving, handling, storage, installation, and inspection procedures in the Instruction Manual
that accompanies the combination Automatic Transfer Switch/Fire Pump Controller. Many of the
procedures in the Installation section are applicable to the Transfer Switch in the adjoining cabinet. For
Transfer Switches sold as an individual unit, and for additional information, follow the procedures below.
Caution: Do not attempt to lift Open Type Transfer Switches with the Shields and
Barriers. The Barriers cannot support the weight of the Transfer Switch.
Page 4 of 22 Pages
Transfer Switch
Receiving and Storage
After receiving the Transfer Switch inspect the cabinet for any damage that may have occurred during
shipping. If the Transfer Switch is not installed immediately, cover the cabinet and store in a dry area.
Condensation can corrode the contacts and other metal parts.
Location
The Transfer Switch should be located as close as possible to the engine generator or to the alternate
power source. If possible, there should be a clear line of sight between the Transfer Switch and the
engine generator.
Line Connections
Refer to the drawings posted inside the cabinet door and in the drawing packet for customer connections.
Before drilling and punching holes in the cabinet for wiring connections, cover the Transfer Switch Power
Panel, inside the enclosure, with a protective covering. Debris falling into the Transfer Switch may jam
the switching mechanism or may cause electrical failure.
Ensure that the normal (primary), emergency (alternate), and load isolation switches are open before
making connections. Connect the load, normal source, and emergency source power cables in the same
phase sequence. Refer to the latest NFPA 70 and Field Connections Wiring Diagram for cable sizes and
torque requirements.
All other standard customer connections are made to TB8 on the left side of the Transfer Switch Power
Panel. Use approved 14-gauge wire for all control connections. Typical field connections are shown
below.
Terminal Connections
Description
TB8-1 and –2
Engine Start Contact, for generator set
TB8-7 and -8
TSNa1 contacts closed, normal position
TB8-9 and -10
TSNa2 contacts closed, normal position
TB8-11 and -12
TSEa1 contacts closed, emergency position
TB8-13 and -14
TSEa2 contacts closed, emergency position
PTB-4(top, 31) and -4(bottom,
S
32)
Emergency Isolation Alarm contacts
(Fire pump transfer switches only)
TSN - Auxiliary Contact, Normal source
TSE - Auxiliary Contact, Emergency source
S
DIN Rail terminal blocks, part of Emergency Isolation Alarm circuit, for use with a remote
or second Alternate Source Isolation Switch indicator.
After installation is complete, perform a transfer test as described in section 6.0 Maintenance.
Page 5 of 22 Pages
Transfer Switch
4.0 Operation
Refer to the schematic and wiring diagrams that are provided with the Transfer Switch. These drawings
are provided in a packet, along with this manual, in the document pocket mounted on the inside of the
cabinet door. A schematic is also posted on the inside of the cabinet door.
The Hubbell Transfer Control Module, LX-301, controls transfer to the emergency source and retransfer
to the normal source. The LX-340 Transfer Switch does not come with a Control Module. A selector
switch initiates transfer and retransfer.
Automatic Operation
Transfer to Emergency Source
The Control Module monitors the normal source phase voltage for acceptable limits of drop-out and
pick-up. A NORMAL OVERRIDE ON MOMENTARY OUTAGE time delay is provided to override voltage
dips causing nuisance starting of the engine generator set. If the normal source voltage is restored above
the pick-up setting within the time delay period, the delay timer is reset.
If the NORMAL OVERRIDE ON MOMENTARY OUTAGE time delay expires before the normal source voltage
is restored, the normal source electronic control initiates engine starting of the generator set and/or
activates the emergency source electronic control. The engine control relay is a 12 VDC latching relay
on the Control Module. The customer connections for the engine start contacts are on TB8 located on
the left side of the Transfer Switch power panel. Refer to the Field Connections Wiring Diagram posted
on the inside of the cabinet door and in the drawing packet for customer connections.
The emergency source electronic control monitors the emergency source for the acceptable voltage and
frequency pick-up levels. When both the voltage and frequency of the emergency source have been
verified, the TCR (Transfer Control Relay) is energized with a 24 VDC signal. The normally open
contacts of the TCR close to power the Transfer Switch drive motor.
The motor is powered by 120 V from the emergency transformer, XFMR-2, applied to the TCR board.
The voltage is rectified on the board and then goes through auxiliary contacts TSEb1 and -b2. From the
auxiliary contacts, 90 VDC is routed to TB1 on the TCR board and then output to the motor. After the
emergency source contacts close, auxiliary contacts TSEb1 and -b2 open to cut power to the motor.
Transfer Switches for fire pumps and Transfer Switches with the NEUTRAL POSITION TIME DELAY,
stop the motor in the neutral position through the braking resistor when auxiliary contacts TSEb3 and
TSNb3 close. After the adjustable time delay expires, Q1 on the TCR board, turns on to bypass contacts
TSEa3 and TSNb3 and power the motor to complete transfer.
An EMERGENCY OVERRIDE ON MOMENTARY OUTAGE time delay is provided to override momentary
voltage dips preventing the Transfer Switch from retransferring to the normal source. If the emergency
source voltage is restored above the pick-up setting within the delay period, the delay timer is reset.
Retransfer to Normal Source
When the Control Module detects that the normal source voltage rises above the pick-up settings, the
timing sequence starts for retransfer to the normal source. The RETRANSFER TO THE NORMAL time
Page 6 of 22 Pages
Transfer Switch
delay starts to allow the normal source to stabilize before retransfer. If the normal source does not meet
pick-up requirements, the delay timer is reset.
At the end of this delay, the TCR is de-energized. The normally closed contacts of the TCR close. The
motor is then powered by 120 V from the normal transformer, XFMR-1, applied to the TCR board. The
voltage is rectified on the TCR board and then goes through auxiliary contacts TSNb1 and -b2. From the
auxiliary contacts, 90 VDC is routed to TB1 on the TCR board and then output to the motor. After the
normal source contacts close auxiliary contacts TSNb1 and -b2 open to cut power to the motor.
Transfer Switches for fire pumps and Transfer Switches with the NEUTRAL POSITION TIME DELAY, stop
the motor in the neutral position through the braking resistor when auxiliary contacts TSEb3 and TSNb3
close. After the adjustable time delay expires, Q1 on the TCR board, turns on to bypass contacts TSEa3
and TSNb3 and power the motor to complete retransfer.
5.0 Standard and Optional Features
Standard Features
The following standard features are provided with the LX-350 Automatic Transfer Switch.
Indicating lights
NORMAL (PL1, Green) When the Transfer Switch is in the normal position (normal source contacts
closed) auxiliary contact TSNa4 closes to power the pilot light.
EMERGENCY (PL2, Red) When the Transfer Switch is in the emergency position (emergency source
contacts closed) auxiliary contact TSEa4 is closed to power the pilot light.
EMERGENCY ISOLATION OPEN (PL3, Yellow) This light is on when the emergency source isolation
switch is open. Standard on Transfer Switches for fire pumps.
Control Module
LED Indicators
EMERGENCY FREQUENCY MONITOR LED (Green) This LED is on when the emergency source
frequency is within the operating range.
EMERGENCY VOLTAGE MONITOR LED (Red) This LED is on when the emergency source voltage is
above the pick-up level.
ENGINE RUNNING UNLOADED LED (Red) This LED is on when the engine generator is running
during the cool down interval.
NORMAL VOLTAGE MONITOR LED (Green) This LED is on when the normal source voltage is above
the pick-up level.
This LED is on during the RETRANSFER TO
NORMAL time delay after the normal source voltage rises above the pick-up level.
RETRANSFER TO NORMAL SOURCE LED (Red)
Page 7 of 22 Pages
Transfer Switch
This LED is on during the TRANSFER TO
EMERGENCY time delay after the emergency source voltage and frequency is above the pick-up level.
TRANSFER TO EMERGENCY SOURCE LED (Red)
Time Delays
This time delay is provided to allow the engine
generator to run for a cool down period after retransfer to the normal source. At the end of this period,
the engine control relay contacts activate to shutdown the engine generator.
ENGINE RUNNING UNLOADED TIME DELAY
This time delay overrides a
retransfer to the normal source when the emergency source voltage is low or drops out momentarily.
OVERRIDE MOMENTARY OUTAGES ON EMERGENCY SOURCE
OVERRIDE MOMENTARY OUTAGES ON NORMAL SOURCE This time delay overrides transfer when
the normal source voltage is low or drops out momentarily.
RETRANSFER TO NORMAL This time delay allows the normal source to stabilize before retransfer.
TRANSFER TO EMERGENCY
This time delay allows the emergency source to stabilize before
retransfer.
Auxiliary Contacts
Auxiliary contacts TSNa1, -a2 and TSEa1, -a2 are available for remote alarms, pilot lights, or other
applications. These contacts are pre-wired for customer connections to TB8-7 through TB8-14. The
contacts are continuously rated at 10 A, 600 VAC.
Manual Disconnect Switch
This feature is not provided with combination Automatic Transfer Switch/Fire Pump Controllers to meet
NFPA 20 specifications.
The Manual Disconnect Switch (MDS) is mounted on the Timer board. This switch isolates the power
source to the gear motor so that the Transfer Switch can only be operated manually with the handle.
TEST push button
The TEST push button simulates a loss of power from the normal source and causes the Control Module
to initiate transfer to the emergency source.
Page 8 of 22 Pages
Transfer Switch
Optional Features
The following items are optional features available with the LX-350 Transfer Switch. Refer to the job
schematic and wiring diagrams for these and other features.
ALTERNATE SOURCE ISOLATION SWITCH (33B)
This option is standard for combination Automatic Transfer Switch/Fire Pump Controllers to meet NFPA
20 specifications.
This circuit breaker provides a means of isolating the emergency source from the Transfer Switch during
installation, testing, and troubleshooting. When this breaker is open, the Engine Start circuit from the
Control Module is open to prevent engine starts during routine maintenance. (The Engine Start circuit is
not included in systems designed for dual utility application.)
BYPASS/RETRANSFER TO NORMAL push button (9)
This option is standard for combination Automatic Transfer Switch/Fire Pump Controllers to meet NFPA
20 specifications.
Pressing this button allows the Transfer Switch to retransfer to the normal position bypassing the
RETRANSFER TO NORMAL SOURCE time delay.
Emergency Isolation Alarm
This option is standard for combination Automatic Transfer Switch/Fire Pump Controllers to meet NFPA
20 specifications.
The Emergency (ALTERNATE SOURCE) Isolation Switch Open Alarm sounds if the isolation switch
breaker is open. When the breaker opens, relay AR1 de-energizes to power the alarm and PL3. Moving
the SAS (Silence Alarm Switch) to the SILENCE position cuts power to the alarm while PL3 stays on
until the breaker is closed. When the breaker is closed, AR1 energizes to power the alarm if the SAS is in
the SILENCE position. Move the SAS switch back to the normal position to silence the alarm. Relay
AR serves the same function as AR1 when the Transfer Switch is in the emergency position.
Normal Disconnecting Means Circuit Breaker (33A)
This option is standard on fire pump and service entrance rated Transfer Switches.
This circuit breaker provides a means of isolating the normal source from the Transfer Switch during
installation, testing, and troubleshooting.
Page 9 of 22 Pages
Transfer Switch
Phase Rotation Monitor
This option is standard for combination Automatic Transfer Switch/Fire Pump Controllers to meet NFPA
20 specifications.
The PRM (Phase Rotation Monitor) prevents the normal power source from supplying power to the LX301 Control Module if the proper phase rotation is not sensed. If the proper phase sequence is not
sensed, the Transfer Switch does not retransfer to the normal source.
Auxiliary Contacts (#15)
Up to three additional NO or NC contacts may be added to the normal and to the emergency source side
of the Transfer Switch. The contacts are rated for pilot duty: 6 A at 250 VAC and 4 A at 380 V.
Battery Charger (#17)
Battery Chargers, 12 and 24 VDC, are available per job specification. The fused Charger circuit is
powered by a 115 V control transformer connected to the load bus of the Power Panel.
BYPASS/TRANSFER TO EMERGENCY push button (#10)
This push button overrides the time delay to transfer to the emergency source.
Overlapped Neutral (#26)
Transfer Switches with a fourth pole are also available. The fourth pole is a neutral pole with makebefore-break contacts. Two pole, 150 A, Transfer Switches may also include a third pole as a neutral
pole.
Plant Exerciser (#16)
The Plant Exerciser option is a seven-day clock that provides for automatic test operation of the
generator set at pre-selected intervals. The clock is powered by a fused circuit from control transformer
XFMR3. The Plant Exerciser option is used in conjunction with contacts (#16A) to initiate engine
starting without load transfer or (#16B) to simulate a power failure with load transfer. A Load/No Load
selector switch (#16C) is available in combination with options 16A and 16B.
Remote Test (#20)
This option provides terminal points for the connection of remote devices that are normally closed and
wired in series with the TEST pushbutton. An open circuit simulates failure of the normal source and
initiates transfer to the emergency source.
Selector Switch (#22)
A four position selector switch for TEST, AUTO, OFF, and ENGINE START is available. When this
option is selected, an OFF indicating light (PL4, white) is included. Turning the switch to the TEST
position initiates a load transfer.
Page 10 of 22 Pages
Transfer Switch
NEUTRAL POSITION TIME DELAY (#6)
This option is standard on Automatic Transfer Switches for fire pumps to meet NFPA 20 specifications.
When the normal source contacts open, the NEUTRAL POSITION TIME DELAY starts. The timer board,
above the TCR board, temporarily opens the gear motor power circuit while the Transfer Switch is in the
neutral position (normal and emergency source contacts open). The adjustable timer is usually set for
three seconds. The green TIMING IN PROCESS LED, on the Timer board, is on when the Transfer
Switch is in the neutral position.
6.0 Maintenance
Danger: Do not touch the Transfer Switch until ALL power is disconnected. Shocks,
burns, or death may result from high voltage.
Caution: Only personnel who are familiar with the power distribution system and this
manual should be allowed to inspect or perform maintenance on the
Transfer Switch.
Preventive maintenance
The following checks should be preformed as part of routine maintenance:
•
A transfer test of the Transfer Switch should be preformed every week.
•
The Transfer Switch should be kept clean of dust and moisture. DO NOT USE A BLOWER TO
CLEAN the Power Panel or the inside of the enclosure. Always use a clean cloth or vacuum to
prevent debris from lodging in the Transfer Switch switching mechanism.
•
Check all wiring connections.
•
Visually inspect the contacts for surface deposits and pitting. This inspection should be preformed
annually.
Transfer Test
After installation, and each week thereafter, check the operation of the Transfer Switch by performing a
manual and an automatic transfer.
Manual Test
Warning:
Manual operation is only for emergency transfers and for testing the
mechanical operating mechanism with normal and emergency power
sources isolated from the Transfer Switch.
Manual operation of the Transfer Switch is performed by inserting the Handle into the Handle Sleeve on
the left side of the Power Panel. Push the Handle up to transfer to the emergency source and down to
Page 11 of 22 Pages
Transfer Switch
transfer to the normal source. Note that when pushing the Handle, the Transfer Switch first opens the
normal source contacts and upon further pushing, closes the emergency source contacts.
Refer to Figure 6-3, page 17, for the location of the Handle Sleeve.
Caution: Do not leave the Handle in the Handle Sleeve. The Handle prevents closure
of the cabinet door and may cause damage to or prevent emergency
operation of the Transfer Switch.
Auto Test
The following procedure is an example for testing the Transfer Switch. A procedure should be written by
qualified personnel that is applicable to the facility, the Transfer Switch options, and the power
distribution system. Steps 1 through 7 are applicable to Automatic Transfer Switches for fire pumps. Go
to step 8 for other applications that do not have an Emergency Isolation Alarm. Refer to job
specifications for timing delays.
1. Check to ensure the emergency source is available or engine generator is set for automatic operation.
2. Move the emergency source isolation switch to the OFF position.
3. Verify that the Emergency Isolation Open light, PL3, is on and the alarm sounds.
4. Switch the SAS to the SILENCE position.
5. Move the emergency source isolation switch to the ON position.
6. Verify that the PL3 goes off and the alarm sounds again.
7. Switch the SAS to the NORMAL position to turn off the alarm.
8. Press the TEST pushbutton until the engine generator starts or Automatic Transfer Switch transfers
if emergency source is a second utility.
9. Verify that the NORMAL indicator goes off and the EMERGENCY indicator comes on per the time
delay settings.
10. Verify that the Transfer Switch transfers to the emergency source.
11. Verify that the Transfer Switch retransfers to the normal position after 30 minutes
or press the BYPASS/RETRANSFER TO NORMAL pushbutton.
12. If the emergency source is a generator set, verify that the engine runs unloaded for five minutes.
Page 12 of 22 Pages
Transfer Switch
Troubleshooting
!
Warning:
Hazardous voltage
will shock, burn,
or cause death.
Do not touch
until ALL power
is disconnected.
DANGER
Disconnect ALL power supply sources to the Transfer Switch before
servicing to prevent shock or accident hazard.
Before troubleshooting perform the following checks:
a. visual inspection for physical damage.
b. ensure that all switches are in the normal operating position.
c. ensure that the engine generator is operational or the alternate source is available.
d. ensure that all wiring connections are secure.
See Table 6-1, page 14, for some examples of possible problems that could occur and actions to repair.
Settings
Voltage and time delay settings are factory set per job specifications. DO NOT CHANGE THESE
SETTINGS WITHOUT CONSULTING HUBBELL. The chart below lists the typical time delay
settings.
Time Delay function
Typical factory setting
Adjustment Range
NORMAL OVER-RIDE ON MONETARY
OUTAGE
1 second, engine generator
3 seconds, utility
0.5 to 6 seconds
RETRANSFER TO NORMAL
30 minutes
2 to 30 minutes
ENGINE RUNNING UNLOADED
5 minutes
2 to 30 minutes
EMERGENCY OVER-RIDE ON MOMENTARY 1 second
OUTAGE
0.5 to 6 seconds
TRANSFER TO EMERGENCY
2 seconds
0 seconds to 5 minutes
NEUTRAL POSITION TIME DELAY
3 seconds
1 second to 10 minutes
60 Hz
30 to 100 Hz
(optional)
Frequency Monitor
Page 13 of 22 Pages
Transfer Switch
Table 6-1 Troubleshooting
Condition
Possible cause
Checks
Action
Switching mechanism
jammed
Isolate power sources
Inspect mechanism for
cause of jam
Actuate Transfer Switch
manually
Transformer fault
Check for 115 V output
from transformers
Replace transformer
Gear motor failure
Use ohmmeter to check
motor windings
Connect DC power
supply to motor leads to
check operation
Replace gear motor
TCR board fault
Inspect board for
damage
Check TC relay
Check board
components with ohm
meter
Repair/Replace TCR board
Phase Rotation
Monitor fault
(ATS/Fire Pump)
Check for correct phase
sequence.
Check PRM w/ ohm
meter
Correct line connections
for proper phase sequence.
Replace PRM
Control Module
Check VOLTAGE
MONITOR LED’s
Repair/Replace Control
Module
Isolation circuit
breaker fault
(ATS/Fire Pump)
Check contacts at TBB1 and –2
Replace Isolation circuit
breaker
Control Module fault
Check Engine Start
Contacts
Repair/Replace Control
Module
Engine generator
continues to run
unloaded
Engine Start Relay
fault
Relay circuit fault
Check relay on Control
Module
Repair/Replace Control
Module
Emergency Isolation
Alarm does not sound
(ATS/Fire Pump)
AR1, AR fault
Check relays and alarm
circuit wiring
Replace faulty relay(s)
Horn fault
Check Horn
Replace Horn
Isolation circuit
breaker fault
Check contacts at TBB4 and –5
Replace Isolation circuit
breaker auxiliary contacts
Transfer Switch does
not transfer
LED’s on Control
Module indicate proper
timing sequence,
voltage, and frequency
Transfer Switch
transfers when
normal source OK
Engine generator does
not start
Emergency Isolation
Alarm sounds
ISOLATION closed
Page 14 of 22 Pages
Transfer Switch
Component Replacement
The procedures in the following subsections provide steps for removing components. Follow the reverse
order of the procedure to replace the components.
Barriers and Shields
Cage Stop
Inside shield
Interphase
Barrier
Inside shield
Pillow Block
SECTION VIEW FROM CENTER OF SWITCH, AT PILLOW
BLOCKS OF YOKE ASSEMBLIES.
(TYP 2 PLACES)
Christmas tree fastener
Cover Top
Plate
Outer Shield
SECTION VIEW FROM INSIDE OF SIDE PLATE.
Side Wall
(TYP 2 PLACES)
Figure 6-1 Barriers and Shields
Exercise caution when removing and installing barriers to avoid breakage.
1. Remove the six slotted hex head bolts to remove the Cover
2. Remove the Christmas tree fasteners to release the Interphase Barriers from the Inside Shields
3.
Remove the bolts on each end of the two Cage Stops to remove the Stops and the Interphase
Barriers
To avoid damaging Arc Chutes do not switch the Transfer Switch with Stops removed and
the Chutes in place.
4. Lift the right Side Wall with Outer Shield from slots
5. Remove the Christmas tree fastener to release the left Side Wall from the Outer Shield
Note
To remove the Christmas tree fasteners place fingers on either side of the fastener to avoid
breaking the Shields and press the fastener out with the flat side of a screw driver tip.
Ensure that the Barriers and Shields do not interfere with movement of Yoke Assembly or Contact Cage
when re-installed.
Warning: Do not re-energize the Transfer Switch unless all Shields and Barriers are
installed.
Page 15 of 22 Pages
Transfer Switch
Arc Chutes
1. Remove the screws on each side of the Chute
2. Inspect the Chute and Arc Grid Plates
Slight burns or arc traces on the plates are normal. Replace the Arc Chute if the plates or the Chute box
have been burnt or damaged.
Moving Contacts
1. Remove the Barriers and the Arc Chutes as described above.
2. Close the emergency or normal contacts to be removed to access the Contact Shunt bolts.
3. Remove the bolts from each Contact Shunt to disconnect the Shunt from the load bus.
4. Manually position the Transfer Switch in the neutral position.
5. Remove the Contact Springs.
Caution: Contact Springs may eject and cause injury during removal or replacement.
Wear safety glasses.
6. Remove the Bowed E-rings from the Contact Pivot Pin.
Stationary Contact
Assembly
Contact
Contact
Spring
Spring Bracket
Pivot Pin
Yoke
Shield
Shunt
Center Contact
Cage Bracket
Arcing
Contact
Lug
Anti Rotation
Plate
Contact Cage
Arc Chute
screw holes
Yoke Bar
Cage Stop
Figure 6-2 Top view of Center Contact
Page 16 of 22 Pages
Transfer Switch
7. Slide the Contact Pivot Pin to the left and then to the right to free Contacts from the Pivot Pin.
Do Not allow the Contact Spacers to fall into the Transfer Switch. Spacers and E-Rings
may cause the switching mechanism to jam.
Notes for re-assembly:
a) Put the short Contact Spacers between the Contact Cage and the Moving Contact. Put the long
Contact Spacers on each side of the Arcing Contact.
b) Replace E-rings on Pivot Pin with bowed side out. Squeeze the sides of the Contact Cage if
necessary.
c) Ensure that the top end of the springs surround the rivet heads and the extrusion in the Contact
Spring Bracket. Also, ensure that they are centered over the Moving Contacts. See Caution under
step 5.
d) Torque the Contact Shunt bolts to 62 inch-pounds.
e) Account for all new and all old parts to ensure no parts are lodged in switching mechanism.
f) Manually switch the Transfer Switch and check the Contacts for alignment. Shields and barriers
should not interfere with movement of Contact Cage or Yoke Assembly.
g) Ensure the Auxiliary Contact Operators close the NO and open the NC contacts.
Mechanical
Interlock Link
Manual Handle
Sleeve
Auxiliary Contact
Operator
Left Side
Assembly
Pointer
Arc Chute
NOR MAL
C L O S ED
PO
SIT
IO
N
EN
0P
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
EN C
E RG
EM
N
OP E
Auxiliary
Contacts
Y P OS I T ION
C LOS E D
X
X
X
X
Figure 6-3 Left side view of Transfer Switch
Page 17 of 22 Pages
Transfer Switch
Stationary Contacts
Replace the Stationary Contacts at the same time the Moving Contacts are replaced.
1. Disconnect the power cable and primary transformer control wire
2. Remove the three flat head screws that hold the Stationary Contact Assembly to the Insulating Base
After replacing the Stationary Contact Assemblies, ensure that the power cables are connected in the
proper phase sequence.
3. Replace the Arc Chutes and the Barriers.
Transformers
1. Note the position of the numbered wires and loosen the terminal screws to release the fork spade
terminals
2. Remove the four mounting screws to remove the transformer from the Power Panel
Ensure that the primary side of the transformer is oriented to the left of the Power Panel when replacing.
Transfer Control Relay board
1. Note the position of and remove the plugs from the Phoenix connectors
2. Loosen the Retainer Bracket screw at the top left standoff
3. Slide the TCR board up and lift from the key slots
Support Bracket
bolts
Lower
Chassis
Upright
Motor Shaft
Support Bracket
Gear Motor
housing bolts
Retainer
Bracket
TCR board
slots
Figure 6-4 Location of TCR board slots and Gear Motor
Page 18 of 22 Pages
Transfer Switch
Gear Motor
1. Manually position the Transfer Switch to the neutral position.
2. Remove the TCR board as described above.
3. Cut the ty-raps to release the wiring harness from the motor leads and the motor housing.
4. Remove the red (TB1-2) and black (TB1-3) motor leads from the Phoenix plug.
5. Remove the four bolts that hold the Motor Shaft Support Bracket from inside the left Lower Chassis
Upright.
6. Remove the left and right bolts holding the gear housing to the Back Panel.
If necessary, note the position of and remove any wires from TB8 to access the left gear housing bolt.
To remove the right bolt, just above the Lower Chassis Upright, obtain a short 7\16” wrench that is
not offset or alter a wench.
7. While supporting the motor, remove the third, top, bolt to remove the gear motor.
Auxiliary Contacts
1. Manually position the Transfer Switch in the neutral position.
2. Remove screws to remove the Lock Plates from the Auxiliary Contact Brackets.
Note the orientation of the auxiliary contacts on the Bracket before removal.
3. Push the Contact mounting tabs to release the contacts from the Bracket.
Before removing contacts from the wiring harness, note the arrangement of the contacts and the wire
connections to avoid cross wiring.
When reinstalling the Lock Plates make sure that they are under the contact mounting tabs.
7.0 Transfer Control Relay Board
Refer to schematic 49255-500.
The purpose of the Transfer Control Relay board is to control the DC gear motor that operates the
Transfer Switch.
Components
1. Two-bridge rectifier, filter capacitor, and MOV circuits
Derives DC power from the normal and the emergency AC power sources for the Transfer Switch
motor and board circuitry.
2. Transfer Control Relay
Controls whether the Transfer Switch is in the normal or the emergency position.
De-energized - Transfer Switch in Normal position
Energized - Transfer Switch in Emergency position
Page 19 of 22 Pages
Transfer Switch
3. Timer circuit (not used on assembly -203)
This circuit determines how long the Transfer Switch stays in the neutral position. Jumper JMP1
selects one of four ranges.
Potentiometer P1 adjusts the time within that range. The four ranges are:
1–6 seconds
20–120 seconds
5–30 seconds
100–600 seconds
4. SCR circuit (not used on assembly -203)
The SCR is turned on at the end of the timing period to complete the neutral position time delay.
Motor current passes through the SCR and steering diodes to the motor.
5. Steering Diodes (not used on assembly -203)
Two diodes steer DC power from either source to the timer circuit and SCR. Two other diodes
block DC power to the motor when the switch is in the neutral position and in time delay. When the
delay period is over the SCR conducts and the diodes steer current to the motor. After the switch
completes the transfer from the normal position to the emergency position, auxiliary contacts on the
switch mechanism interrupt the motor current and stop the motor. To transfer back to the normal
position the polarity of the current going to the motor is reversed by de-energizing the TCR.
6. Manual Disconnect Switch (not used on assembly -201)
Opening this switch disconnects the motor from the circuit. A transfer must be done manually using
the handle.
7. Motor breaking resistor (not used on assembly -203)
This resistor is connected across the motor windings to stop the motor quickly when the Transfer
Switch enters the neutral position. This is done so that the motor does not continue to rotate and
complete the transfer before the timer circuit times out.
Assembly versions
For LX-350
49255-201
Does not include the MDS switch. A soldered in jumper selects the Auto mode.
49255-202
Includes all circuit components.
49255-203
Does not include the timing circuit, the SCR circuit, steering diodes, LED, or the motor
breaking resistor.
For LX-340
49255-204
Consists of rectifier and timing circuits only.
49255-205
Consists of rectifier circuits only.
Page 20 of 22 Pages
Transfer Switch
8.0 Spare Parts and Drawing References
The following lists contain part numbers and drawing numbers for identification and for ordering. If
materials are needed from Hubbell, contact the local Hubbell representative to request the desired
information or parts.
Spare Parts
Description
Part No.
Terminal Lug
150 A
260 A
400 A
82303-001
82304-001
82305-001
Cover Top Plate
2/3 Pole
4 Pole
82315-009
82315-010
Inside Shields
Outer Shields
Description
Part No.
Arc Chute, 1 pole
Arc Chute, 3 pole
82315-300
82315-302
Auxiliary Contact a, NO
Auxiliary Contact b, NC
57471-462
57471-463
1
1
Phase Rotation Monitor
208–260 V
440–480 V
57418-398
57418-399
1
82315-018
82315-017
Transformer
208/230/460 V
230/460/575 V
57511-343
57511-345
1
1
Side Wall Assembly
82315-008
Interphase Barrier
82315-011
49255-201
49255-202
49255-203
1
Yoke Shield
82315-050
Christmas Tree Fastener
82315-701
LX-350 TCR Board
w/ Timer, w/o Switch
w/ Timer, w/ Switch
w/o Timer, w/ Switch
LX-340 TCR Board
w/ Timer, w/o Switch
w/o Timer, w/o Switch
Black Push Button
302045120
Contact Block,
for Push Button
NO
NC
57471-462
57471-463
AR relay, 2 pole
31658-123
AR1 relay, 3 pole
31658-112
AR relay socket
Spares
2 Years
3
49255-204
49255-205
Gear Motor Assembly
82315-311
Red Light Socket
402161420
Green Light Socket
402161320
1
120 V Bulb
80324-905
1
Manual Handle
82315-108
48518-018
18 point terminal strip
57520-362
AR1 relay socket
48518-019
DIN Rail terminal blocks
57520-365
Fuse, ¾ A
302016020
Plant Exerciser, SPDT
302017420
Fuse Block
302015920
Plant Exerciser, DPDT
302018320
Load/No Load Toggle Switch
302019420
Battery Charger, 2 A, 12 VDC
302002220
Rotary Selector Switch
302017520
Battery Charger, 2 A, 24 VDC
302002320
1
1
2
Spares
2 Years
2
Page 21 of 22 Pages
Transfer Switch
Description
Part No.
Spares
2 Years
Description
Part No.
Spares
2 Years
Contact Replacement Kits
(Moving and Stationary Contacts included)
150 A
1 Main Pole
3 Main Pole
Neutral Pole
82303-070
82303-071
82303-072
260 A
1 Main Pole
3 Main Pole
Neutral Pole
82304-070
82304-071
82304-072
400 A
1 Main Pole
3 Main Pole
Neutral Pole
82305-070
82305-071
82305-072
LX-301 Control Modules
Standard
For Fire Pump applications
200 V/3 pole/60 Hz
90363-001
200 V/3 pole/60 Hz
90363-009
208 V/3 pole/60 Hz
90363-002
208 V/3 pole/60 Hz
90363-010
220 V/3 pole/60 Hz
90363-003
220 V/3 pole/60 Hz
90363-011
230 V/3 pole/60 Hz
90363-004
230 V/3 pole/60 Hz
90363-012
240 V/3 pole/60 Hz
90363-005
240 V/3 pole/60 Hz
90363-013
440 V/3 pole/60 Hz
90363-006
440 V/3 pole/60 Hz
90363-014
460 V/3 pole/60 Hz
90363-007
460 V/3 pole/60 Hz
90363-015
480 V/3 pole/60 Hz
90363-008
480 V/3 pole/60 Hz
90363-016
Engine Start Relay, 12 VDC
31658-076
LX-301 Main Board
49203-101
LX-301 Signal Board
49203-201
1
Drawing References
Drawing No.
Title
Drawing No.
Title
82303-350
General Assembly, 150 A
82305-350
General Assembly, 400 A
82304-350
General Assembly, 260 A
49255-500
Schematic-Transfer Switch
Control
Notes
As built schematics and wiring diagrams are provided as part of the drawing packet supplied with each
Transfer Switch.
Refer to Bulletin 1000 for information about one year parts and labor warranty.
Page 22 of 22 Pages