Applicable Systems
Hydraulic

Symptoms

The Hydraulic reports a main contactor fault. The main contactor failed to close or open as expected during the power-on sequence.

Possible Causes

  • Main contactor coil failure or control circuit fault
  • Contactor contacts welded or excessively worn
  • Contactor control wiring loose or disconnected

Troubleshooting Steps

  1. Step 1: Check the contactor coil voltage and continuity in the drive
    Coil receives correct voltage and has proper resistance
  2. Step 2: Inspect the contactor contacts for welding or excessive wear
    Contacts are clean and make proper contact
  3. Step 3: Verify the contactor control wiring is intact and connected
    Control wiring is properly connected

How to Reset

To reset: Fix or replace the main contactor, then reset and restart.

Source: Parker Hydraulic System Manual, Parker Hannifin Corporation

Category: Hydraulic & Pneumatic