Resistor braking 175
the average power dissipation. This average value can be used to represent an
equivalent continuous braking power, where C is the cycle time (see page 173):
= ________________ W (watts)
Calculate the maximum braking power P
gen,max
and the equivalent continuous
braking power P
gen,ave
for the motor.
Resistor choice
P
gen,ave
is the value to use when assessing which brake resistor to use. However, a
safety margin of 1.25 times is recommended to ensure the resistor operates well
within its limits
1
, so:
Required resistor power rating = 1.25 × P
gen,ave
__
______________ W (watts)
The range of suitable brake resistors is shown in the following table. Choose the
resistor
that has a power rating equal to or greater than the value calculated above.
WARNING! The brake resistance must be 39 Ω or greater to ensure the
drive’s maximum regeneration switching current (10 A) is not exceeded.
Failure to observe the minimum resistance could result in damage to the drive. See
Brake resistor connection on page 154.
1. The brake resistors listed in the following table can withstand a brief overload of 10 times
the rated power for 5 seconds. Please contact ABB if larger power ratings are required.
Part Resistance Power rating
RGJ139 39 Ω 100 W
RGJ160 60 Ω 100 W
RGJ260 60 Ω 200 W
RGJ360 60 Ω 300 W
To Next Page
Loading...
Need help?
General
