Brake chopper short-circuited
Danfoss · VLT Micro Drive FC 51
¿Qué significa 27 ?
The internal brake transistor (chopper) within the drive, which is responsible for switching the brake resistor, has short-circuited. This renders the regenerative brake function inoperative and can cause immediate faults or damage if the drive attempts to use it.
Causas comunes
- Failure of the IGBT (Insulated Gate Bipolar Transistor) within the brake chopper circuit due to overcurrent or overvoltage stress.
- Contamination or foreign material bridging terminals on the power board, creating a short path for the brake chopper.
- Aging and degradation of semiconductor components leading to internal breakdown of the chopper circuit.
- Repeated high-energy braking events exceeding the chopper's continuous power dissipation rating.
Pasos de reparación & Lista de verificación
Haga clic en los pasos para seguir su progreso.
- 1
Safely disconnect all incoming power to the drive and wait for DC bus discharge (verify 0VDC at DC+ / DC- terminals).
- 2
Measure resistance between the drive's DC+ terminal and the B1/B2 brake terminals; a reading near 0 Ohms indicates a short circuit.
- 3
Visually inspect the drive's power board for signs of damage, burning, or conductive debris near the brake chopper components.
- 4
If an internal short is confirmed by measurements, replace the entire drive as the brake chopper is an integrated component.
- 5
Before applying power to a new drive, verify the external brake resistor's impedance matches the drive's specifications.