ekran Inc.
330 Nantucket Boulevard, Toronto, Canada
M1P 2P4
+1-416-449-3084 Fax: +1-416-449-9298 info@tekran.com
Technical Note 309: Pump Drive Upgrade Kit
Part No:
90-13309-00
Rev 1.01
Purpose
Under certain unusual conditions, Model 1130 pump modules can blow the speed control FET (field
effect transistor). This results in the pump either running full speed or not at all. The PUMP toggle
switch on the front panel of the Pump Module does not control the pump if this type of failure occurs.
This kit provides an upgraded pump unit FET assembly and grounding link. The kit should be
installed as a preventative measure even if no problems have been observed.
How can I tell if the FET has already been Upgraded?
Old FETs are branded with the part number: IRFP250. New FETs bear the part number
location of the FET is shown in the figure on the next page.
IRFP2907.
The
Kit Contents
Item
1
2
3
4
5
Description
FET terminal strip assembly
Terminal strip mounting H/W
Grounding strap
Ground strap mounting H/W
FET Insulating wafer
Notes
- Complete with insulated diode shoulder washer (top)
- 2x 4-40 ½” long screw & 2x #4 lockwashers (internal tooth type)
- Green, 14” long wire assembly
- 6-32 ¼” long screw & #6 lockwasher & #10 lockwasher
- Soft rectangular wafer with single hole.
FET mounting H/W
Diode Mounting H/W
Cable Ties
- 4-40 3/8” long screw & #4 lockwasher
- 4-40 x ¼” long screw & #4 split ring lockwasher
- 4x nylon cable ties
(May already be attached to back of FET.)
6
7
8
Tools Required
-
Screwdrivers: large & small common slot & Philips
Volt/ohm meter
- Side cutters
Installation
Part A – Grounding Strap
Refer to the figure, right for details. The grounding strap [3] is a length of
green wire that is connected between a screw on the head of the Thomas
Pump [A] and a pre-existing threaded insert on the base plate [B].
1. Turn off power and remove the top cover of the Model 1130 Pump
Module.
2. Connect the end of the green strap [3] with the large (#10) ring lug to
the pump head [A]. Ensure that the lock washer is reinstalled between
the screw head and the circular wire lug on the strap.
3. Using the 6-32 x ¼” long screw and #6 lock washer provided [4],
connect the end of the strap with the small (#8) hole lug to the preexisting threaded insert on the base plate located in front of the buffer tank. See location [B] on figure.
4. Route the wire so that it does not rub against any tubing and secure it with the four cable ties supplied. If
required, clip any existing cable tie straps. Clip the excess length on each tie.
NEW DIRECTIONS IN ENVIRONMENTAL TECHNOLOGY
- Page 1 of 2 -
TN_309_Pump_Drive_Upgrade.doc Rev: 03/2003
ekran Inc.
330 Nantucket Boulevard, Toronto, Canada
M1P 2P4
+1-416-449-3084 Fax: +1-416-449-9298 info@tekran.com
Part B – FET Terminal Strip
Refer to figure, right, for details.
1.
2.
3.
4.
5.
6.
7.
Ensure that power is OFF and that
the top cover is removed.
A four-pin cable and connector, J7
labeled Linear Supply In is located
on the circuit board directly above
the terminal strip. Temporarily
disconnect this connector and move
the attached cable out of the way.
(The photo shows this cable already
removed.)
Note the location of the four wires
connected to the five positions on
the existing terminal strip. In
particular identify the two heavy
black wires at the bottom of the
strip. One, terminal [#5] located at
the bottom of the strip , goes to the
negative terminal of the capacitor;
the other [#4] connects to the black wire on the pump motor.
Remove the screws holding the existing diode and FET in place. Remove the two screws holding the terminal strip.
Remove the existing assembly, including the thermal insulating washers that are located under the diode and FET.
Position the new assembly. Note that the metal tab of the diode contains a plastic insulating washer on the top of the
mounting hole and has a thermal washer attached to its mounting surface. Place the insulation washer supplied with
the kit under the FET and align it so that the hole in the washer is directly underneath the FET mounting hole. (See
Figure.)
Mount the new assembly by using the 4-40 by ¼” long screw and #4 split-ring lockwasher for the diode, a 4-40 3/8”
long screw and #4 lockwasher for the FET and the two screws originally removed from the old terminal strip. Do not
reattach the four wires to the strip yet.
Caution: The metal bottom plates of both the diode and the FET must be electrically isolated from the base plate.
However, they must both make good mechanical contact with the base plate to allow the transfer of heat.
The insulated thermal washers and, in the case of the diode, the top plastic washer, serve to insulate the
metal body components of these devices from the chassis. You must use an ohmmeter to confirm that the
metal tabs of the diode and the FET are not shorted to ground.
8. Testing the Ohmmeter. Set the multi-meter to the Ohms range and touch the two test leads to two different grounded
points on the chassis of the pump module. The meter should read zero ohms while contact is maintained.
9. Testing the Diode. Place one test lead on a convenient grounded point on the chassis and one on the top right screw
terminal [#1] of the terminal strip. An open circuit should be seen between these two points.
10. Testing the FET. Place the test leads between terminal [#4] and ground. This must also be an open circuit.
11. Reconnect the four wires as shown at the table to the right. Ensure that the wires are fully seated and that the screws
are firmly tightened.
12. Reconnect the cable assembly you disconnected in step #2,
Terminal Wire Type Function
above, to J7 on the PCB.
#1 (Top)
Red (Thick)
Positive Supply
13. Turn on the pump module and test for proper operation of the
#2
No Connection Internal pump motor tie point
pump. (The PUMP toggle switch on the front panel should turn
#3
Red (Thin)
FET Gate Drive (to PCB)
the pump ON and OFF.)
#4
Black
(Thick)
To Pump Motor
14. Check that all wires and cables are securely tied and that no
cables or tubing are rubbing against each other.
#5 (Bottom)
Black (Thick)
Negative Supply
NEW DIRECTIONS IN ENVIRONMENTAL TECHNOLOGY
- Page 2 of 2 -
TN_309_Pump_Drive_Upgrade.doc Rev: 03/2003