Olympia Millennium-E - Scr;Diode Block

EnForcer™ SCR Service Manual I.B. 1561
29
WARNING: Be sure to install phase A, phase B, and phase C wires to their proper terminals in the front of the charger (A
is on the left, C is on the right).
When installing primary leads into the terminal blocks, take special precaution in preparing the double-wire
leads (wires #2 and #5) for insertion into the terminal blocks.
6) Connect the transformer’s control voltage wires to the fuses.
WARNING: Be sure to install 7A, 7B, and 7C in proper order (A is on the left, C is on the right). If they are not connected
properly, a phase control problem will occur.
7) Connect the secondary leads to the SCR/Diode Blocks. Again, be careful to connect phase A to phase A, phase
B to phase B, etc.
SCR / DIODE BLOCK
Specifications for mounting SCR / Diode Blocks on Flat Aluminum Heat Sinks:
Surface
1) No scratches, gouges, or burrs allowed in the SCR / Diode block contact area.
2) No oil, dirt, paint, adhesive or other foreign substances are permitted in the contact area.
3) Apply a light coating of heat sink thermal compound to the flat side of the SCR / Diode Block.
Mounting Instructions
1) Tighten the nut with your fingers as far as possible. Then use the torque wrench. Do not exceed the torques
shown in the following table.
2) Do not use any other wrench to tighten the nut.
SCR / Diode Block Mounting Torque (in/lb) Buss Bar Mounting Torque (in/lb) SCR / Diode Block
Size
Bolt Size Max Bolt Size Max
104 Amp 10-32 X 1.25 19.0 5mm 31
162 Amp 10-32 X 1.25 19.0 6mm 65
250 Amp 10-32 X 1.25 19.0 8mm 132
285 Amp 10-32 x 1.25 19.0 8mm 132
Removal
The SCR / Diode Blocks cannot be removed until the buss bars are removed first. These steps explain how to remove
the heat sink.
1) Remove the DC cable leads.
2) Remove the DC control leads (red) from the PC board.
3) Unplug the SCR / Diode Blocks gate leads.
4) Remove the secondary transformer leads from the input of the SCR / Diode Block.
5) Unscrew the two buss bars from the SCR / Diode Blocks. Note on the units where the buss bar is directly
attached to the jumper wire, leave the buss bar attached to the jumper wire and just move the buss bar away from
the SCR / Diode Blocks.
6) Now you can remove the SCR / Diode Block from the heat sink.
Replacement
1) Remove old silicone-heatsink compound from the heatsink.
2) Apply silicone heatsink compound (i.e., thermalloy 249, Aavid 1001, etc.) to the SCR / Diode Block and fasten it to
the heatsink. (Use the proper torque. See table above.)
3) Replace the heatsink into the charger case, being careful to slide it onto its holder.
4) Mount the two buss bars back to the SCR / Diode Blocks.
5) Connect the secondary transformer leads to the inputs of the SCR / Diode Blocks.
6) Reconnect the SCR / Diode Block gate leads.
7) Connect the DC control leads to the PC board.
8) Replace the DC cable leads.