ABB ACH580-31 - Selecting a Custom Brake Resistor

Note: 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.
￭
Selecting a custom brake resistor
If you do not use an ABB resistor,
1. make sure that the resistance of the custom resistor is greater than or equal
to the resistance of the default ABB resistor.
where
Resistance of the custom resistor R
Resistance of the default resistor R
min
WARNING!
Never use a brake resistor with a resistance smaller than R
min
. This will
cause overcurrent that will damage the brake chopper and the drive.
2. make sure that the resistance of the custom resistor does not restrict the
braking capability needed, ie.
where
Maximum power generated by the motor during braking P
max
Drive intermediate DC circuit voltage. U
DC
1.35 · 1.2 · 415 V (when supply voltage is 380 … 415 V AC)
1.35 · 1.2 · 500 V (when supply voltage is 440 … 500 V AC) or
Resistance of the custom resistor R
3. make sure that the resistor can dissipate the energy transferred to it during
the braking:
• Braking energy is not greater than the resistor heat dissipation capacity
( E
r
) during the period specified. See the custom resistor specification.
• The resistor is installed in a correctly ventilated and cooled space.
Otherwise the resistor cannot meet its heat dissipation capacity and
overheats.
4. make sure that the instantaneous load capacity of the custom resistor is
greater than the maximum power taken by the resistor when it is connected
to the drive intermediate DC circuit by the chopper:
244 Resistor braking