6KBU300
—————— STANDARD BRAKING RESISTANCES —————— 6
1
6. STANDARD BRAKING RESISTORS
In order to simplify the choice of the resistor that has to be used, here below the values of the normalized resistors
are reported, calculated on a criterion for a typical use.
POVL Overload power that can be regenerated by the inverter, equal to the rated power mul-
tiplied by factor 1.36 (inverter’s overload = Icont x 1.36)
PAVBR
Average power dissipated by the resistor, where the duty cycle is equal to 10%
EBR Maximum instantaneous energy that the resistor can dissipate
tOVLBR Maximum continuative braking time in overload conditions (POVL)
tBR Maximum continuative braking time at drive rated load conditions
PNBR
Rated continuous power of the resistor which must be equal or greater than the average
power P
AVBR
T
C
P,n
P
PBR
T
BR
n
E
BR
t
The ohmic value of the normalized resistors has been calculated in order to assure the braking current for the limit
use of 6KBU300, that is to say a 460Vac supply of the inverter (braking threshold 745Vdc).