ABB ACS800-U4 Hardware Manual page 106

106
Note: A resistor other than the standard resistor can be used provided that:
• its resistance is not lower than the resistance of the standard resistor.
WARNING! Never use a brake resistor with a resistance below the value specified
for the particular drive / brake chopper / resistor combination. The drive and the
chopper are not able to handle the overcurrent caused by the low resistance.
• the resistance does not restrict the braking capacity needed, i.e.,
where
P
U
R
• the heat dissipation capacity (E
above).
Resistor braking
2
U
DC
P
max <
R
maximum power generated by the motor during braking
max
voltage over the resistor during braking, e.g.,
DC
1.35 · 1.2 · 415 VDC (when supply voltage is 380 to 415 VAC),
1.35 · 1.2 · 500 VDC. (when supply voltage is 440 to 500 VAC) or
1.35 · 1.2 · 690 VDC (when supply voltage is 525 to 690 VAC).
resistor resistance (ohm)
) is sufficient for the application (see step 3
R