F07906 — Armature short-circuit / internal voltage protection: Parameterization error

F07906 reports that the armature short-circuit or the internal voltage protection is parameterized incorrectly: the selected function does not match the connected motor, the Motor Module in use, or the wiring and interconnections that the selected variant requires. The drive stores the fault value in r0949 — interpreted as a decimal number it has the form zzzzyyxx, in which zzzz gives the fault cause and xx the affected motor data set. The message value decodes as “Fault cause: %1, motor data set: %2”.

• The armature short-circuit is incorrectly parameterized: it has been selected although the configured motor type does not permit it, or the selected external variant is not completely wired and interconnected (output r1239.0 not wired, contactor feedback signal at p1235 not interconnected in all CDS, or no delay time entered in p1237).
• The internal voltage protection does not match the Motor Module and motor actually used: the Motor Module maximum output current (r0209) is less than 1.8 x the motor short-circuit current (r0331), the Motor Module is not in booksize or chassis format, the motor short-circuit current (p0320) is greater than the maximum motor current (p0323), or the activation is not given for all motor data sets with synchronous motors.

1. Read the fault value in r0949 as a decimal number and determine the fault cause and the affected motor data set from it.
2. Fault cause 1: an armature short-circuit / voltage protection is only permissible for permanent-magnet synchronous motors — the highest position of the motor type in p0300 must either be 2 or 4.
3. Fault cause 101: control the contactor using output signal r1239.0, for instance connected to an output terminal via binector input p0738. Before this fault can be acknowledged, p1231 must be set again.
4. Fault cause 102: connect the contactor feedback signal to an input terminal (e.g. r0722.x) and interconnect it to p1235 — or select the external armature short-circuit without contactor feedback signal (p1231 = 2).
5. Fault cause 103: with the variant without contactor feedback signal (p1231 = 2), parameterize a delay time in p1237. This time must always be greater than the actual contactor opening time, as otherwise the Motor Module would be short-circuited!
6. Fault cause 201: use a Motor Module with a higher maximum current or a motor with a lower short-circuit current; the maximum Motor Module current must be higher than 1.8 x the short-circuit current of the motor.
7. Fault cause 202: for the internal voltage protection, use a Motor Module in booksize or chassis format.
8. Fault cause 203: for the internal voltage protection, only use short-circuit proof motors, so that p0320 does not exceed p0323.
9. Fault cause 204: either activate the internal voltage protection for all motor data sets with synchronous motors (p1231 = 3) or deactivate it for all motor data sets (p1231 not equal to 3).

• 1 — A permanent-magnet synchronous motor has not been selected.
• 2 — No induction motor selected.
• 101 — External armature short-circuit: output (r1239.0) not wired.
• 102 — External armature short-circuit with contactor feedback signal: no feedback signal connected (BI:p1235); the feedback signal must be interconnected in all command data sets (CDS).
• 103 — External armature short-circuit without contactor feedback signal: the wait time when opening (p1237) has not been parameterized.
• 201 — Internal voltage protection: the maximum output current of the Motor Module (r0209) is less than 1.8 x motor short-circuit current (r0331).
• 202 — Internal voltage protection: a Motor Module in booksize or chassis format is not being used.
• 203 — Internal voltage protection: the motor short-circuit current (p0320) is greater than the maximum motor current (p0323).
• 204 — Internal voltage protection: the activation (p1231 = 4) is not given for all motor data sets with synchronous motors (motor type in p0300 = 2 or 4).

• r0949 — read the fault value here, interpreted as a decimal number: it yields the fault cause and the affected motor data set.
• p0300 — motor type: the armature short-circuit / voltage protection requires a permanent-magnet synchronous motor, i.e. the highest position of the motor type must be 2 or 4.
• p1231 — set the armature short-circuit / DC braking configuration here: p1231 = 1 selects the external variant with contactor feedback signal, p1231 = 2 the variant without; set it again before fault cause 101 can be acknowledged; for fault cause 204 activate with p1231 = 3 for all synchronous motor data sets or deactivate with a value not equal to 3.
• p1235 — interconnect the external armature short-circuit contactor feedback signal here, in all CDS, for example from an input terminal such as r0722.x.
• p1237 — enter the external armature short-circuit delay time when opening; it must be greater than the actual contactor opening time.
• r0209 — maximum output current of the Motor Module: compare it against 1.8 x the motor short-circuit current (fault cause 201).
• r0331 — motor short-circuit current: the second value in that comparison.
• p0320 — motor short-circuit current: for the internal voltage protection it must not be greater than the maximum motor current.
• p0323 — maximum motor current: the upper limit for p0320 (fault cause 203).
• p0738 — binector input via which output signal r1239.0 can be routed to an output terminal to control the external armature short-circuit contactor.

The fault is acknowledged immediately once the parameterization has been corrected; only then does the drive allow a new start. Two causes tie the acknowledgement to a condition: before fault cause 101 can be acknowledged, p1231 must be set again, and fault cause 204 can only be acknowledged once the internal voltage protection is activated or deactivated uniformly across all motor data sets.