Sinclair SCV-750EB Service Manual page 151

Procedure
If possible, switch the compressors and start up again. If the problem persists, replace the two compressors.
6.15 L60: Fan motor phase loss protection
Description
Compressor has phase loss protection.

After the fault, the compressor stops running, and if the fault disappears after one minute, the compressor starts again.

Trigger/resume condition
Trigger condition: The compressor wire is not connected or has poor contact.

Resume condition: Check the wiring of the compressor. After wiring again, the phase loss protection fault is eliminated.

Reset method: Automatic recovery after reaching the fault exit condition.

Possible causes
 The compressor wire is not in good contact or the terminal screws are not tightened.
Module board is abnormal.

Procedure
Check the UVW output connection wire of the compressor drive board, and check the UVW wiring of the compressor;

If possible, switch the compressor wire to confirm whether the drive board is normal, otherwise replace the drive board.

6.16 L61: Short circuit to ground protection
Description
Compressor has short circuit to ground protection.

After the fault, the compressor stops running, and if the fault disappears after one minute, the compressor starts again.

Trigger/resume condition
Trigger condition: Compressor has short circuit to ground protection.

Resume condition: Check whether the compressor casing is damaged, resulting in poor insulation.

Reset method: Automatic recovery after reaching the fault exit condition.

Possible causes
The compressor casing is in poor insulation.

Procedure
 Disconnect the compressor wire, measure the compressor UVW resistance to ground, confirm and replace the compressor.
6.17 L65: IPM short circuit protection
Description
The IPM corresponding to the compressor has short circuit protection.

After the fault, the compressor stops running, and if the fault disappears after one minute, the compressor starts again.

Trigger/resume condition
Trigger condition: The IPM corresponding to the compressor has short circuit protection.

Resume condition: Replace the drive board.

Reset method: Automatic recovery after reaching the fault exit condition.

Possible causes
There is a problem with drive board.

Procedure
Check whether the IPM virtual welding and the PWM related transmission circuit of the MCU are connected to the welding.

If so, change the replace the drive board.
6.18 L6b: Open circuit of U-phase lower tube
Description
Open circuit of U-phase lower tube.

After the fault, the compressor stops running, and if the fault disappears after one minute, the compressor starts again.

149