Back EMF protection

What does 27 mean?

The drive has detected that a magnetized motor is already rotating when a start command is issued. This is particularly relevant for Permanent Magnet (PM) motors which generate back electromotive force even when unpowered, making them appear 'active' during startup.

• Back EMF voltage exceeds the maximum limit during deceleration.
• Inadequate braking torque control.
• High inertia load causing over-speeding on power loss.
• Incorrect braking parameter settings (P1-25).
• External braking resistor not functioning correctly.

Click steps to track your progress.

1. 1

   Ensure that there is no rotating Permanent Magnet (PM) motor connected and spinning when the start command is given to the frequency converter.