Calculating The Maximum Braking Power (P Br ); Example 1; Example 2 - ABB ACS800 Hardware Manual

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Calculating the maximum braking power (P
• Braking energy transferred during any ten minute period must be less than or
equal to the energy transferred during the reference braking cycle.
• The braking power must not exceed the rated maximum value P
1.
2.
n
P
t
P

Example 1

Duration of a braking cycle is 30 minutes. The braking time is
15 minutes.
Result: If the braking time exceeds 10 minutes, the braking is considered
continuous. The allowed continuous braking power is 10% of the Maximum Braking
Power (P

Example 2

Duration of a braking cycle is three minutes. The braking time is
40 seconds.
1.
P
2.
Result: The maximum allowed braking power for the cycle is 37% of the rated value
given for the reference cycle.
Resistor braking
n x P x t
br br
P < P
br brmax
= Number of braking pulses during
a ten minute period
= Maximum allowed braking power (kW).
br
= Braking time (s)
br
= Maximum Braking Power
brmax
for a reference cycle (kW)
).
brmax
P
brmax
P <
br
4 x 40 s
P
br
brmax
t
br
T = Duration of braking cycle
P < P
br brmax
)
br
< P x 60 s
brmax
x 60 s
= 0.375 x P
brmax
600 s
O.K.
brmax
t
.