ABB ACS560 Hardware Manual page 184

184 Resistor braking
WARNING!
Do not use a brake resistor with a resistance below the minimum value
specified for the particular drive. The drive and the internal chopper are not
able to handle the overcurrent caused by the low resistance.
Stop time for an application
Stop time is the time required for the load speed to reach zero.
Equation for calculating stop time:
, where,
t on = stop time in seconds
= load inertia in kgm 2
J
n start = speed of motor in rpm
n end = motor stop speed in rpm
T load
= load torque, torque required for the application
For example, if
J
T load
n start
n stop
then stop time,
Example for selecting a brake resistor
If,
the selected drive = ACS560-01-04A0-4
motor power = 1.5kW
(P Rmax )
stop time (t on ) = 30s
running time (T) = 180s
then,
= 60 kgm 2
= 800 Nm
= 1000 rpm
= 0