TB Wood's WFC1000 Series, Installation, Operation And Maintenance Instructions

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B. Power Wiring
Power wiring is those wires which are connected during installation to the power circuit terminals, L1, L2,
L3, M1, M2, and M3. Power wiring must be selected as follows:
1. Use only UL ® recognized wire.
2. Wire voltage rating must be a minimum of 300 V for 230 VAC systems, and 600 V for 460 VAC
systems.
3. Wire gauge to be selected based on continuous input and output currents. See Table 1.5 for
current information.
4. Grounding must be in accordance with NEC and CEC.
NOTE: Power delivered from variable frequency controls contains high frequencies which may
cause interference with other equipment. Control wiring and line wiring should not be run in the
same conduit or raceway with inverter-to-motor wiring.
Where power wiring is longer than 50 feet, increase the wire size to the next larger gauge size to reduce
the voltage drop in the wire.
C. Control Wiring
Control wiring is wiring connected during installation to the control terminal strip (30 terminals). Control
wiring must be selected as follows:
1. Shielded, twisted wire is recommended to prevent electrical noise interference from causing
improper operation or nuisance tripping. Recommended wires are Belden types; equivalents may
be substituted:
8761 (300V – 60°C – UL ® -2-wire)
8771 (300V – 60°C – UL ® -3-wire)
8719 (600V – 60°C – UL ® -2-wire)
2. Use only UL
®
recognized wire.
3. Wire voltage rating must be a minimum of 300 V for 230 VAC systems, and 600 V for 460 VAC
systems. This is Class 1 wire.
4. Never run the control wiring in the same conduit or raceway with power wiring. See NOTE above.
5. Connect shield to inverter COM terminal only.
2.7 Reducing Current Surges and Voltage Transients
Inrush currents to the coils of magnetic contactors, relays and solenoids associated with, or in close proximity
to, the inverter can induce high current spikes in the power and control wiring, causing faulty inverter operation.
If this condition occurs, a snubber network, consisting of a series resistor and capacitor for AC loads, or a free-
wheeling or flyback diode for DC loads, should be placed across the relay coil to prevent the occurrence. The
following component values should be used for 115 VAC or 230 VAC relays or solenoids.
For Main Circuit Contractors and Solenoids For Auxiliary Control Circuit Relays
C = 0.2 MFD, 500 VDC R = 500
Ω
5 Watts C = 0.1 MFD, 500 VDC R = 200
Ω
, 2 Watts
Connection Diagram
for AC and DC Relay
Coils and Solenoids
14
FIGURE 2.7
For magnetic contactors, relays and solenoids which are energized from a DC source, a free-wheeling diode
should be used. The diode should be a high-speed, fast recovery type. Connect the diode across the coil as
shown above. The diode current and voltage should be selected by the following formulae:
Diode Current Rating (A) Coil Capacity (VA)
Rated Voltage of Coil (V)
Diode Voltage Rating Rated Voltage of Coil (V) x 2
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