F07822 — Monitoring underspeed threshold fallen below fault

F07822 is raised by the Control Unit when the monitored speed falls below the fault threshold set for the lower speed. The fault threshold for the lower speed was fallen below. The monitoring only reacts when it is enabled with p2149.6 = 1 — or automatically for a separately excited synchronous motor running in closed-loop torque control without an encoder (p1300 = 20, p1501 = 1). The fault is only output while the machine is excited, which r0056.4 = 1 shows; once the value has been fallen below, status bit r2199.0 is set to 1. Depending on the drive's configuration, the same condition can also be issued with no reaction.

• The monitored speed has fallen below the fault threshold configured for the lower speed (p2161, with the hysteresis p2150).

1. Confirm the condition on the drive: r2199.0 = 1 indicates that the value has been fallen below (remember the fault is only output while the machine is excited, r0056.4 = 1).
2. Check the parameterization of p2161 and p2150 — the threshold and the hysteresis of this monitoring.
3. If required, reduce the load.
4. For generator applications, switch on an additional unit.

• p2149 — Monitoring configuration: set bit 6 (p2149.6 = 1) to switch this underspeed monitoring on.
• p2161 — Speed threshold 3: the lower-speed fault threshold of this monitoring; check its setting when F07822 trips.
• p2150 — Hysteresis speed 3: the hysteresis of this monitoring; check it together with p2161.
• r2199 — Status word monitoring 3: bit 0 (r2199.0 = 1) tells you that the value has been fallen below.
• p1300 — Open-loop/closed-loop control operating mode: p1300 = 20 (torque control) is part of the combination in which the underspeed monitoring is active automatically.
• p1501 — BI: Change over between closed-loop speed/torque control: with p1300 = 20 and p1501 = 1 the monitoring is automatically active for a separately excited synchronous motor without an encoder.

The drive coasts down when this fault trips and must be acknowledged before it will start again. Remove the cause first (see the checks above), then acknowledge the fault immediately and restart the drive. In the configuration that issues this condition with no reaction, the drive takes no action and there is nothing to acknowledge.