Resistor braking 241
21
Resistor braking
Contents of this chapter
This chapter describes how to select, protect and wire brake choppers and resistors.
The chapter also contains the technical data.
When is resistor braking necessary?
Resistor braking is necessary for high capacity braking if a regenerative drive cannot
be used.
Operation principle and hardware description
The drive can be equipped with optional built-in brake chopper (+D150). Brake resistors
are available as add-on kits.
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.
Planning the braking system
Generic guidelines
■
This section contains generic brake cable type, length and placing instructions, rules
on how to minimize electromagnetic interference and descriptions and requirements
for protections.