ABB ACS880-07, Hardware Manual

Page: 267 / 274

Resistance of specified resistors (per chopper). This is also the minimum allowed resistance for the
resistor assembly. R
Maximum short-term (1 min every 10 mins) braking power P
brmax
Maximum continuous power rating P
brcont
Maximum peak current I
max
Maximum braking power for the specified duty cycle P
br
Rms current for the specified duty cycle I
rms
￭ SAFUR resistor data
IPxx P
Rcont
(kW)
E
R
(kJ)
R
(ohm)
U
N
(V)
Type
IP00 9.0 3600 4.0 500 SAFUR125F500
IP00 10.5 4200 3.4 575 SAFUR210F575
IP00 13.5 5400 2.7 500 SAFUR200F500
IP00 15.0 6000 2.4 460 SAFUR180F460
Nominal voltage U
N
Resistance R
Short energy pulse that the resistor assembly will withstand each 400 seconds E
R
Continuous power (heat) dissipation of the resistor whenplaced correctly. Energy E
R
dissipates in
400 seconds.
P
Rcont
Degree of protection IPxx
￭ Terminals and cable lead-through data of factory-installed
chopper/resistor cubicles
See the dimension drawings delivered with the unit.
Planning the braking system
￭ Verifying the load capacity of the braking equipment
1. Calculate the maximum power generated by the motor during braking ( P
max
).
2. Ensure that the maximum power rating of the braking equipment is equal to or greater
than
P
max
.
The P
brmax
values specified in the ratings table are for the reference braking cycle
(1 minute of braking, 9 minutes of rest). If the actual duty cycle does not correspond to
the reference cycle, either use the power rating given for the other two reference cycles
(
P
br
), or calculate the maximum braking power for a custom braking cycle. See below
for instructions on calculating P
br
for other braking cycles.
3. Check the resistor selection. The energy generated by the motor during a 400-second
period must not exceed the heat dissipation capacity of the resistor (
E
R
). If you use
custom resistor(s), see also the separate instructions below.
If the
E
R
value of the resistor is not sufficient, it is possible to use a four-resistor assembly
in which two resistors are connected in parallel, two in series. The E
R
value of the
four-resistor assembly is four times that of a single resistor.
Resistor braking 267