KEB COMBIVERT F4-S Serie Manual De Instrucciones página 65

Attention Fire Risk!
Connection of the
braking resistor
In order to detect the overheating of a braking resistor it is absolutely
necessary to monitor the temperatur switch. The overheating can have
following causes:
• ramps too short or the operation-time too long
• incorrect dimensoning of the braking resistor
• input voltage too high
• defect of braking transistor in the inverter or the braking module
The disconnection of the mains voltage offers the only protection in the
case of a defective braking transistor (see diagram).
Braking resistors can develop a very high surface temperature, therefore
install as safe-to-touch as possible!
• +/PA, PB Terminals for the braking resistor
• during release of the temperature monitoring the input voltage is
switched off
U
230 or 24 V AC/DC
drive
A simplified protection is achieved, if the links of the temperature sensor
are integrated into the temperature detection in accordance with following
drawing. This measure does not protect with a defect of the braking
transistor however against the developing extreme overload with acute
danger of fire.
PA
PB
= 90°C
OH1
OH2
at 24 V AC/DC
check tripping
L1
L2
L3
+/PA
--
PB
U
V
W
OH
O H
GB - 27
GB