Cause : HW monitoring active.

That hardware fault (P0947 = 22 and P0949 = 1) caused by the following events:

(1) DC-link overcurrent = short circuit of IGBT
(2) Short circuit of chopper
(3) Earth fault
(4) I/O board is not properly inserted.

Since all these faults are assigned to one signal on the power stack, it is not possible to establish which one actually occurred.

Diagnosis & Remedy

First you must see if the fault is permanent (i.e. the inverter cannot be started without the fault occurring) or sporadic (occurs occasionally or in certain defined operating conditions).

Permanent F0022 fault:
- Check the I/O board. It has to be fully pressed home.
- Is there an earth fault or short circuit on the output of the inverter or in an IGBT? Disconnecting the
motor cables will establish which of these.
In the case where the fault occurs permanently when all external wiring (apart from mains) is disconnected, then the unit almost certainly has a defect and should be repaired.

Sporadic F0022 fault:
This should be treated as "overcurrent". The following may cause the sporadic occurrence of F0022:
- Sudden load changes or mechanical blockages.
- Very short ramp times.
- If the Sensorless Vector Control is badly optimized.
- If an incorrect braking resistor of too low a resistance is fitted.