Toshiba G3, Рабочая тетрадь

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For additional assistance, please contact Toshiba Adjustable Speed Drive Marketing Dept. at (800) 872-
2192
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Bypass Control
Introduction
Among the many special functions the G3 can realize is a inverter/bypass control. Bypasses are utilized to
provide operation of the motor across-the-line (ATL) in the event of a drive fault or during inspection of
the drive. All devices shown external to the drive will have to be provided. The bypass scenario can also
make use of the drive’s ability to “catch” a spinning motor, which is useful when transferring an ATL
motor to the drive.
Connections
Notes
¾
The contacts are shown in an unenergized coil state.
¾
An additional contactor may be included to isolate the drive, thereby allowing the cycling of drive
power while in bypass.
ST
S2
F
CC
3
C4
C3 MCCB
Enable
Inverter
Bypass
M
G3
RCH C
LOW C
RCH A
LOW A
V(+)
CONTROL
R2
R1
R4
C2
V(-
C1
R3
Overload
Relay
¾
An overload relay (OLR) is necessary in a bypass scenario because the drive’s built-in motor thermal
protection is not in the circuit in the bypass mode.
¾
A normally open (NO) contact from the OLR should be put across the S1 and CC terminals of the
drive.
¾
The interposing relays (R3 and R4) shown above may not be necessary; the RCH and LOW output
contacts of the G3 are rated for 250 VAC, 1 A for inductive loads; compare with the burden of your
bypass and output contactors’ coils.