F07928 — Internal voltage protection initiated

F07928 is raised when the Motor Module signals that the motor is short-circuited through the power semiconductors — the signal r1239.5 = 1 — while the internal voltage protection is selected (p1231 = 3). In this state the pulses cannot be enabled, and the armature short-circuit function of the Motor Module is the mechanism behind the fault. The manual describes the code identically for the Power Module on S120/S150 and on G130/G150, so everything below applies to all four families.

• The Motor Module has signalled that the motor is short-circuited through the power semiconductors; the condition is stored as r1239.5 = 1.
• The internal voltage protection is selected (p1231 = 3), so the pulses cannot be enabled and the drive trips with OFF2.

1. Check whether your Motor Module supports the autonomous internal voltage protection: r0192.10 = 1 in the power unit firmware properties means it does. In that case the Motor Module decides by itself, from the DC link voltage, whether the armature short-circuit is activated.
2. With the autonomous function, the armature short-circuit is activated and OFF2 is initiated as soon as the DC link voltage exceeds 800 V. The armature short-circuit is withdrawn once the DC link voltage falls below 450 V.
3. If the motor is still in a critical speed range, the armature short-circuit is re-activated as soon as the DC link voltage again exceeds the threshold of 800 V, so expect the fault to return in this situation.
4. If the autonomous internal voltage protection is active (r1239.5 = 1) and the line supply returns with the DC link voltage between 450 V and 800 V, the armature short-circuit is withdrawn after 3 minutes. Wait for this time before expecting the drive to enable pulses again.

• p1231 — Armature short-circuit / DC braking configuration (ASC/DCBRK config): this is where the internal voltage protection is selected; the fault presupposes the setting p1231 = 3.
• r0192 — Power unit firmware properties 1 (PU FW properties 1): read bit r0192.10 here; a value of 1 shows that the Motor Module supports the autonomous internal voltage protection.

The fault must be acknowledged immediately once the condition has cleared, and the drive does not start again until it has been acknowledged. The underlying condition clears by itself: the armature short-circuit is withdrawn when the DC link voltage falls below 450 V, or — if the autonomous internal voltage protection is active (r1239.5 = 1) and the line supply has returned with the DC link voltage between 450 V and 800 V — after 3 minutes. Only then can the pulses be enabled again and the drive restarted.