Motor Thermal Overload Fault

¿Qué significa OL1 ?

The OL1 fault is triggered when the motor connected to the drive experiences prolonged overcurrent, causing it to exceed its thermal capacity. This protection is configured by parameters like L1-01 (protection selection) and L1-02 (overload time constant). Continuing to operate a motor in an OL1 condition severely risks damage to motor windings and insulation, leading to premature motor failure and costly downtime.

• Motor rated current (Parameter L1-01) set incorrectly in the drive, below the actual motor nameplate Full Load Amps (FLA).
• Mechanical overload on the motor shaft due to increased friction, binding, or a seized bearing in the driven equipment.
• Drive acceleration/deceleration times (Parameters C1-01, C1-02) set too short for the load inertia, leading to excessive peak current during transients.
• Supply voltage imbalance exceeding 2% at the drive input terminals (L1, L2, L3), causing higher current in one motor phase.
• Motor cooling fan failure or obstructed cooling fins on the motor itself, leading to insufficient heat dissipation.

Haga clic en los pasos para seguir su progreso.

1. 1

   Read the motor nameplate and verify that Parameter L1-01 (Motor Rated Current) in the drive matches the motor's Full Load Amps (FLA). Adjust if necessary.

2. 2

   Measure the actual current (Amps) on all three motor phases using a clamp meter (e.g., Fluke 376 FC) during normal operation and compare to the value set in L1-01.

3. 3

   Disconnect power and manually rotate the motor shaft and connected load. Verify smooth, free rotation without excessive resistance or binding.

4. 4

   Using an insulation tester (e.g., Megger MIT420), perform a motor winding insulation resistance test from each phase to ground (500VDC for 1 minute).

5. 5

   Monitor motor temperature directly with a thermal imager (e.g., FLIR T540) and compare to the motor's insulation class limits (e.g., Class F, 155°C).

6. 6

   Verify supply voltage balance at the drive input terminals (L1, L2, L3) using a multimeter (e.g., Fluke 87V) and ensure phase voltages are within 2% of each other.