DYNAMIC BRAKING UNIT DBU-400 Frequency converters

Frequency converters (Inverters) with DC bus and input diode rectifier bridge are suitable for the
operation of three phase AC-motors in two drive quadrants, motoring in both directions of rotation.
Braking with more than 10% of the rated inverter current is only possible with a braking unit.
Without a braking unit, an excessively rapid deceleration causes an increase in the DC bus voltage.
The regulator responds by
• shut-down due to DC bus overvoltage tripping (e.g. on GV3000: Fault HU)
• extending the set deceleration rate or increasing the output frequency depending on parameter
setting.
By the use of a Dynamic Braking Unit (DBU) and braking resistor the energy in the DC bus circuit can
be converted to heat.

DYNAMIC BRAKING UNIT DBU-400

After removing the cover plate of the DBU the blue jumper plug with positions 460V / 415V is accessible
at the upper edge of the regulator card (middle on BUC, right on BUA).
This jumper plug defines the DC bus voltage at which the DBU switches the DB resistor to the DC bus.
When delivered from stock the DBU is adjusted for safety reasons to 460 V line voltage.
NOTE: If the blue jumper plug is missing, the DBU is set to 415V.

For the GV3000 Inverters on line voltages up to 415 V the blue jumper plug must be set to position 415.
For the GV3000 Inverters on line voltages above 415 V and all the other inverters VTI / VCI / VGI type
460 V, GMI, GP2000 and SP500 the jumper must stay in position 460.