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When are brake resistors required on AC Altivar drives?

Issue:
Are brake resistors required on AC drives?

Product Line:
Altivar drives

Environment:
ATV61 ATV71 ATV312

Cause:
Installation / Setup

Resolution:
AC variable frequency drives are commonly used with a variable speed drive system. For applications that require faster deceleration rates, or where motor speeds are exceeding the synchronous speed set by the output frequency of the drive ( an overhauling load condition), a braking resistor is required. Braking resistors increase the braking torque capability of a variable frequency drive, producing faster and more controlled braking. The resistor dissipates regenerated power to keep the bus voltage from exceeding the rated limit of the drive.