15
Resistor braking
Contents of this chapter
This chapter describes how to select, protect and wire brake choppers and resistors.
The chapter also contains technical data
Operation principle and hardware description
Frames R1 to R4 have a built-in brake chopper as standard. Frames R5 and up 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
￭ Selecting the brake circuit components
1.
Calculate the maximum power generated by the motor during braking (P
max
).
2. Select a suitable drive, brake chopper and brake resistor combination for the
application from the rating table in this chapter. The braking power of the chopper
must be greater or equal than the maximum power generated by the motor during
the braking.
3. Check the resistor selection. The energy generated by the motor during a 400-second
period must not exceed the resistor heat dissipation capacity E
R
.
Resistor braking 263
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