240
System Manual – MOVIDRIVE® compact Drive Inverters
4
Selecting the braking resistor
Project Planning
Calculation-
example
Given:
•
Peak braking power 13 kW
•
Average braking power 6.5 kW
•
Cyclic duration factor cdf 6 %
Required:
•
Braking resistor BW..
Procedure
1. Determine the overload capacity.
First determine the overload factor for a cyclic duration factor cdf of 6 % from the re-
spective diagrams.
2. Calculate the continuous braking power.
Calculate the continuous braking power (= 100 % cdf braking power) using the fol-
lowing formula:
Mean braking power / overload factor
Results:
100 % cdf braking power for wire resistors: 685 W.
100 % cdf braking power for grid resistors: 856 W.
3. Determine the maximum braking resistor value depending on MOVIDRIVE
®
.
For an MC_4_A...-5_3 (AC 400/500 V unit), the maximum braking resistor value
is 72
Ω
at a peak braking power of 13 kW (
→
table Peak braking power).
For an MC_4_A...-2_3 (AC 230 V unit), the maximum braking resistor value is
18
Ω
at a peak braking power of 13 kW (
→
table Peak braking power).
4. Select the matching braking resistor:
Select the matching braking resistor from the assignment tables (AC 400/500 V units
or AC 230 V units) on the basis of the following aspects:
– Maximum braking resistance value
– MOVIDRIVE
®
unit used
Result when using, e.g. MC_4_A0110-5_3: BW039-012 (or braking resistor with
higher power)
Result when using, e.g. MC_4_A0110-2_3: BW018-015-T (or braking resistor with
higher power)
Summary of Contents for MOVIDRIVE compact MCH41A
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