Resistor Braking; Contents Of This Chapter; Safety; Operation Principle - ABB ACS380 Hardware Manual

Resistor braking

Contents of this chapter

The chapter describes how to select the brake resistor and cables, protect the system,
connect the brake resistor and enable resistor braking.

Safety

WARNING!
Do not do work on the brake resistor or the resistor cable when the drive is
energized. A dangerous voltage is present in the resistor circuit, even when the
brake chopper is not operating, or when it is disabled by a parameter.

Operation principle

The brake chopper handles the energy generated by a decelerating motor. The extra
energy increases the DC link voltage. The chopper connects the brake resistor to the
intermediate DC circuit whenever the voltage in the circuit exceeds the limit defined by
the control program. Energy consumption by the resistor losses lowers the voltage until
the resistor can be disconnected.

Selecting the brake resistor

Drives have a built-in brake chopper as standard equipment. The brake resistor is
selected using the table and equations shown in this section.
1. Determine the required maximum braking power P
must be smaller than P . Refer to Reference brake resistors (page
BRmax
Resistor braking 175
12
for the application. P
Rmax Rmax
177).