ABB NBRA-656 - Appendix B: Maximum Braking Power; Calculating Maximum Braking Power

Installation and Start-up Guide for NBRA-6xx B-1
Appendix B – Maximum Braking Power
How to Calculate?
The Maximum Braking Power (P
BRmax
) for each standard
ACS 600/braking chopper combination is given in Table 2-1 and
Table 2-2 in Chapter 2 – Overview. The rated value is specified for a
reference braking cycle (ten minute braking cycle: one minute braking,
nine minutes at rest). If the actual braking cycle does not correspond to
the reference cycle, the maximum allowed braking power must be
calculated.
1.
Braking energy transferred during any ten minute period must be
less than or equal to the energy transferred during the reference
braking cycle.
2.
The braking power must not exceed the rated maximum value
P
BRmax
.
Example 1
Duration of a braking cycle is 30 minutes. The braking time is
15 minutes.
Result: If the braking time exceeds ten minutes the braking is
considered continuous. The allowed continuous braking power is ten
percent of the Maximum Braking Power (P
BRmax
).
n · P
BR
· t
br
< P
BRmax
· 60 s
n = Number of braking pulses during
a ten minute period
P
BR
= Maximum allowed braking power (kW).
t
br
= Braking time (s)
P
BRmax
= Maximum Braking Power
for a reference cycle (kW)
P
BR
< P
BRmax
1.
2.