System Manual – MOVIDRIVE® compact Drive Inverters
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Selecting the braking resistor
Project Planning
4.8
Selecting the braking resistor
Parallel
connection
Two braking resistors with the same value must be connected in parallel for some
inverter/resistor combinations. In this case, set the trip current on the bimetallic relay
to twice the value of I
F
entered in the table.
Peak braking
power
Due to the DC link voltage and the resistance value, the peak braking power can be less
than the load capacity of the braking resistor. The peak braking power is determined as
follows:
U
DC
is the maximum permitted DC link voltage. Its value is
– U
DC
= DC 970 V for MOVIDRIVE
®
compact MC_4_A...-5_3 (AC 400/500 V units)
– U
DC
= DC 485 V for MOVIDRIVE
®
compact MC_4_A...-2_3 (AC 230 V units).
DANGER!
The supply cables to the braking resistor carry a high DC voltage (ca. DC 900 V).
Severe or fatal injuries from electric shock.
•
The braking resistor cables must be suitable for this high DC voltage.
•
Install the braking resistor cables according to the regulations.
WARNING!
The surfaces of the braking resistors get very hot when the braking resistors are loaded
with P
rated
.
Risk of burns and fire.
•
Choose a suitable installation location. Braking resistors are usually installed on top
of the control cabinet.
•
Do not touch the braking resistors.
NOTES
•
The data applies to BW..., BW...-T and BW...-P braking resistors.
•
For BW..., BW...-T and BW...-P braking resistors, plan for a load derating of 4 % per
10 K from an ambient temperature of 45 °C. Do not exceed a maximum ambient
temperature of 80 °C.
•
The overload factor of the BW..-T and BW...-P braking resistors is limited by using
an integrated temperature relay:
– BW...-T up to overload factor 12
– BW...-P up to overload factor 40
•
The maximum permitted line length between MOVIDRIVE
®
and the braking re-
sistor is 100 m.
04994AXX
P
U
R
DC
max
=
2
Summary of Contents for MOVIDRIVE compact MCH41A
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