Kohler MPAC 1200 / MPAC 1500 — Solenoid and Rectifier Replacement Procedure, 40-225 Amp Models
Repair & overhaul
For the Kohler MPAC 1200 / MPAC 1500, from the Kohler service manual.
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Before you start
- Spring-loaded parts. Wear protective goggles when servicing spring-loaded parts. Hold parts securely during disassembly.
- Disassembling the solenoid. The spring in the solenoid assembly exerts substantial force on the coil.
Procedure
- Prevent all connected generator sets from starting; disconnect the starting battery, negative lead first.
- Disconnect main power and open the ATS enclosure; verify zero volts across each phase.
- Remove the DC fast-on connections from the rectifier terminals.
- Check the coil resistance; replace the coil if infinite or shorted.
- Remove the AC fast-on connections; check the diode operation of the rectifier.
- Install a new rectifier with the red dot in the upper right corner.
- Connect the AC fast-on connections to the AC terminals.
- Remove tie wraps; remove the front bolt and loosen the rear bolt of the coil securing strap.
- Remove the coil; lubricate the spring and plunger assembly.
- Insert and seat the spring into the new coil; install the plunger.
- Install the new coil and coil holding strap; tighten the bolts.
- Connect the DC fast-on connections to the DC terminals of the rectifier.
- Install tie wraps; close the enclosure and reconnect power.
- Enable the generator set and test operation.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: Kohler service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.