X5 AC Drive User’s Manual
Chapter 4: Connections
DPD00089A
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© 2009 Vacon Incorporated All Rights Reserved
4.3.4 Single-phase Operation
X5 AC drive 230 Vac, 5-HP models are designed for both three-phase and single-phase input power.
If one of these models is operated with single-phase power, use any two line input terminals. The
output of the device will always be three-phase.
The safe derating of the X5 series of drives is 50% of the nominal current (HP) rating. Consult the
factory with the particular application details for exact derating by model.
4.3.5 Ground Fault Circuit Interrupters (GFCI)
The GFCI breakers are designed for residential use to protect personnel from stray currents to
ground. Most GFCI breakers will shut off at 5 mA of leakage. It is not uncommon for an AC drive
to have 30 to 60 mA of leakage.
4.3.6 Motor Lead Length
803 (PWM
Frequency)
.
Nuisance trips can occur due to capacitive current flow to ground. These currents can cause shock
to personnel and can create problems within the motor. Care should be taken when working in these
areas.
Some applications can have a restricted lead length because of type of wire, motor type, or wiring
placement. Consult the factory and the motor manufacturer for additional information.
4.3.7 Using Output Contactors
Contactors in the output wiring of an AC drive may be needed as part of the approved safety circuit.
Problems can arise if these contactors are opened for the safety circuit and the drive is left in run
mode of operation. When the contactor is open, the drive is in a no-load, no-resistance state, but is
still trying to supply current to the motor. However, when the contactor closes, the drive sees the
motor resistance and instantly demands current. This inrush of current when the contactor closes can
fault or cause failure to the drive.
To prevent problems, interlock an auxiliary contact to the drive’s Run or Enable circuit to stop the
drive when the contactor opens. In this way, the drive will be disabled and no inrush will occur when
the contactor is closed again.