Appendix B Accessories|VFD-B-P Series
B-6 Revision April 2009, SW V1.00
resistor heats up, the resistance would increase with temperature, and brake torque would
decrease accordingly. Suggest cycle time is one minute
100%
T0
T1
Brake Time
Cycle Time
ED% = T1/T0x100(%)
8. For safety reasons, install a thermal overload relay between brake unit and brake resistor.
Together with the magnetic contactor (MC) in the mains supply circuit to the drive it offers
protection in case of any malfunctioning. The purpose of installing the thermal overload relay is
to protect the brake resistor against damage due to frequent brake or in case the brake unit is
continuously on due to unusual high input voltage. Under these circumstances the thermal
overload relay switches off the power to the drive. Never let the thermal overload relay switch
off only the brake resistor as this will cause serious damage to the AC Motor Drive.
R/L1
S/L2
T/L3
NFB
MC
VFD Series
MOTOR
O.L.
U/T1
V/T2
W/T3
+P
-N
()
()
B1
B2
SA
R/L1
S/L2
T/L3
MC
IM
BR
O.L.
Thermal
Overload
Relay or
temperature
switch
Surge
Absorber
Thermal Overload
Relay
Brake
Resistor
Brake
Unit
+P
-N
()
()
Note1: When using the AC drive with DC reactor, please refer to wiring diagram in the AC drive
user manual for the wiring of terminal +(P) of Brake unit.
Note2: wire terminal -(N) to the neutral point of power system.
Do NOT
Temperature
Switch