Toshiba TOSVERT VF-MB1 Instruction Manual page 30

Motors with a brake
When motors with a brake are directly connected to the inverter's output, the brake cannot be released
at startup because of low voltage. Wire the brake circuit separately from the main circuit.
MC1
3-phase
FLB FLC S2 (ST)
power
source
MC1
MC3
Circuit diagram 1
In circuit diagram 1, the brake is turned on and off through MC2 and MC3. If you do not wire it as shown
in diagram 1, an over-current trip may occur because of a bound current during brake operation.
(Example of running preparation ST assigned to terminal S2.)
In circuit diagram 2, the brake is turned on and off by using low-speed signal OUT.
In some situations, such as with elevators, turning the brake on and off with a low-speed signal may be
appropriate. Be sure to contact us before designing your system.
Measures to protect motors against surge voltages
In a system in which a 500V-class inverter is used to control the operation of a motor, very high surge
voltages may be produced. When applied to the motor coils repeatedly for a long time, may cause
deterioration of their insulation, depending on the cable length, cable routing and types of cables used.
Here are some examples of measures against surge voltages.
(1) Lower the inverter's carrier frequency.
(2) Set the parameter f316 (Carrier frequency control mode selection) to 2 or 3.
(3) Use a motor with high insulation strength.
(4) Insert an AC reactor or a surge voltage suppression filter between the inverter and the motor.
MC2
B
IM
CC
MC3
MC3
MC2
A-17
MC2
MC1
NO CC P24
OUT
3-phase
power
+
–
source
RY
RY
MC2
Circuit diagram 2
E6581697
B
IM
1