EnForcer™ SCR Service Manual I.B. 1561
26
SCR/DIODE BLOCK
WARNING: Faulty SCR/Diode Blocks may cause voltage to be present at the DC cables.
Physical Test
If you do not have a clamp-on meter to check for current in the 3 SCR/Diode Blocks, you can perform the following to
locate a fault in the secondary phase:
1) Start the charger, and run it for 5 minutes with a battery connected.
2) Turn off the charger and disconnect the battery.
3) Within 1 minute, check the temperature of the SCR/Diode Blocks. If an SCR/Diode Block is cold, then it is
defective.
WARNING: Heatsink and SCR/Diode Blocks may be very warm. Please exercise caution.
First SCR/Diode Block Test
Please follow these steps before testing the SCR/Diode Blocks:
Disconnect the battery.
Disconnect the AC power.
You will be testing the SCR/Diode Blocks to see whether there is continuity or forward leakage current (100K ohms or
less).
1) Disconnect the gate leads from SCR/Diode Blocks:
2) Remove the transformer-input connection to the SCR/Diode Block (anode).
3) Using an ohmmeter, set to its 1k scale, check for continuity between each SCR/diode Block (anode) input
connection and + bussbar. The ohmmeter should read infinity.
4) If continuity is shown, replace the SCR/diode Block.
5) If infinity (open) is measured in both directions, the SCR/Diode Block may be open. To prove the SCR/Diode
Block functions properly, you need to go to the next test (Second SCR/Diode Block Test) to check the gating
operation of the SCR/diode block.
Second SCR/Diode Block Test
Please follow these steps before testing the SCR/Diode Block:
Disconnect the battery.
Disconnect the AC power.
You can test a single SCR/Diode Block at a time. You will need a Flashlight tester or a Continuity tester with 2 AA
batteries in it to do this.
Please follow these steps:
1) Disconnect the three phase input wires to each of the SCR/Diode Blocks.
2) Disconnect the nylon connector from the SCR/Diode Block (gate drive).
To Next Page
Loading...
