Toshiba 48-1250 A 用户手册

Two types of SCRs are used in the TX Series depending on the horsepower/
amperage rating of the unit.  Isolated SCRs are used in smaller units and
“hockey puck” type SCRs are used in larger units.  (Refer to Chapter 9 for
the main control board layout.)

• Remove both line and control power from unit, tag and lock out.

   Failure to remove both line and control power
   before starting this procedure may cause personal
   injury or death.

• Label the location of wires connected to the SCR.
• Remove the mounting screws, lugs and associated wiring from the
  existing SCR.
• Make sure the surface to which the power module mounts is clean
  and free from dirt, nicks and scratches.
• Apply thermal grease uniformly along the mounting surface of the
  SCR. Spread the grease thinly (3 mil thick) to completely cover
  the base of the power module and minimize air pockets.  The
  grease must be free of contamination.
• Replace the screws and tighten down firmly.  All mounting screws
  should be 44 lb/in.  Units with a maximum amperage rating of up to

48A, should use 26 lbs/in busbar and power lugs.  Units with a

  maximum amperage of  78A - 120A should use 44 lbs/in busbar
  and power lugs.
• Reconnect all busbars, lugs and wires. Check to make sure the
  gate and cathode are wired correctly. Use the following chart to
  verify the wiring of J5, J6 and J7:
• After verifying that all wiring is correctly connected, test the SCR.