Resistor braking
159
Resistor braking
What this chapter contains
This chapter describes how to select, protect and wire brake choppers and resistors.
The chapter also contains the technical data.
Availability of brake choppers and resistors for the ACS800
Frame R2 and R3 drives and 690 V units of frame size R4 have a built-in brake
chopper as standard equipment. For other units, brake choppers are optionally
available as built-in units, indicated in the type code by +D150.
Resistors are available as add-on kits.
Selecting the correct drive/chopper/resistor combination
1. Calculate the maximum power (P
max
) generated by the motor during braking.
2. Select a suitable drive / brake chopper / brake resistor combination for the
application according to the following tables (take account of other factors in the
drive selection also). The following condition must be met:
where
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
.
If the E
R
value is not sufficient, it is possible to use a four-resistor assembly in which two standard
resistors are connected in parallel, two in series. The E
R
value of the four-resistor assembly is four
times the value specified for the standard resistor.
P
br
denotes P
br5
, P
br10
, P
br30
, P
br60
, or P
brcont
depending on the duty cycle.
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