A07929 — Drive: No motor detected

A07929 ("Drive: No motor detected") is raised when the absolute current value is so small after enabling the inverter pulses that no motor is detected — the current does not reach the output load identification current limit (p2179). Depending on how the drive is configured, the same condition can also be output as a fault rather than as this alarm.

The inverter takes no automatic action on this alarm, and no acknowledgement is required. In the case of vector control and an induction motor, this alarm is followed by fault F07902. On the G120XA with a PM330 power module, correction currents are calculated and displayed in the optimized pulse pattern range.

• The absolute current value is so small after enabling the inverter pulses that no motor is detected — the measured current stays below the threshold in p2179. Both the G120 and the G120XA manual give this as the single cause; no other causes are listed.

1. Check the motor feeder cables.
2. Reduce the threshold value in p2179 — the manual names this measure explicitly for synchronous motors.
3. Increase the threshold value (PM330) — this step is described for the G120XA with a PM330 power module.
4. Check the voltage boost of the U/f control (p1310).
5. Carry out a standstill measurement to set the stator resistance (p0350).

• p2179 — Output load identification current limit: the threshold evaluated after the pulses are enabled; reduce it when the alarm appears, e.g. for synchronous motors.
• p1310 — Starting current (voltage boost) permanent: check this voltage boost of the U/f control as one of the remedies for this alarm.
• p0350 — Motor stator resistance cold: set it by carrying out a standstill measurement, as the manual prescribes for this alarm.

The alarm requires no acknowledgement, and the inverter takes no automatic action when it is raised. Remove the underlying cause first: check the motor feeder cables, adjust the thresholds (p2179, or the PM330 threshold on the G120XA), check the U/f voltage boost (p1310) and, if required, set the stator resistance (p0350) via a standstill measurement. Once the current after enabling the pulses is large enough for a motor to be detected, the alarm no longer appears.