A07903 — Drive: Motor speed deviation

A07903 reports that the motor speed is not following its setpoint closely enough: the absolute difference between the speed setpoint and the smoothed speed actual value (r2169) has exceeded the tolerance threshold p2163 for longer than the monitoring tolerates (p2164, p2166). The alarm is only enabled when p2149.0 = 1. Depending on the drive, one setpoint (p2151) or two setpoints (p2151 and p2154) are monitored against the actual value.

• The load torque is greater than the torque setpoint.
• When accelerating, the torque, current or power limit is reached — and if the limits are not sufficient, the drive may have been dimensioned too small.
• In closed-loop torque control, the speed setpoint does not track the speed actual value (not every manual lists this cause).
• The Vdc controller is active.
• With U/f control, the overload condition is detected because the I_max controller is active.

1. Increase p2163 and/or p2166 so that brief speed deviations no longer trip the alarm.
2. Increase the torque, current and power limits; if they are genuinely insufficient for the load, the drive has probably been dimensioned too small.
3. For closed-loop torque control, make sure the speed setpoint tracks the speed actual value.
4. If the monitoring is not wanted for the application, deactivate the alarm by setting p2149.0 = 0.

• p2149 — monitoring configuration: bit 0 must be 1 for this alarm to be active, and p2149.0 = 0 is the manual's way to switch A07903 off.
• p2151 — speed setpoint (CI) that the deviation monitoring compares with the actual speed.
• p2154 — second speed setpoint (CI); on drives that monitor two setpoints it is evaluated together with p2151.
• r2169 — smoothed speed actual value (CO) against which the setpoints are checked.
• p2163 — the velocity threshold the speed difference must stay below to avoid the alarm.
• p2164 — hysteresis belonging to that speed threshold.
• p2166 — off-delay time that defines how long the deviation is tolerated before A07903 comes.

No acknowledgement is needed for this code: it is an alarm without a fault reaction, and it clears itself once the speed difference falls back within the p2163 tolerance for the tolerated time. If it keeps returning, work through the checks above instead of merely raising the thresholds.