ABB NBRA-656 - Page 52

Appendix B – Maximum Braking Power
B-2 Installation and Start-up Guide for NBRA-6xx
Example 2
Duration of a braking cycle is three minutes. The braking time is
40 seconds.
Result: The maximum allowed braking power for the cycle is 37 % of
the rated value given for the reference cycle.
Example 3
Duration of a braking cycle is three minutes. The braking time is
10 seconds.
Result: The maximum allowed braking power for the cycle is equal to
the Maximum Braking Power (P
BRmax
) given for the reference cycle.
P
BRmax
t
P
BR
600 s
P
BR
<
P
BRmax
· 60 s
4 · 40 s
= 0.375 · P
BRmax
t
br
T = Duration of the braking cycle
1.
2. P
BR
< P
BRmax
O.K.
T = Duration of the braking cycle
t
br
P
BRmax
t
P
BR
600 s
P
BR
<
P
BRmax
· 60 s
4 · 10 s
= 1.5 · P
BRmax
1.
2. P
BR
> P
BRmax
Not allowed.