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N700E INSTRUCTION MANUAL
2-6
2.1.2 Power Circuit Wiring
High voltage power supply is applied to the VFD. Each terminal and wiring procedure is respectively
described in this section.
!
WARNING
For all wiring work, wait at least for 5 Minutes when the power is turned off
Use a voltage meter to make sure no AC voltage is present on R, S, T.
Use a voltage meter to make sure no voltage is present on the DC bus.
Verify the charge lamp is not illuminated
Be aware that even after shutting of the power supply, there is a time for the
capacitors to dissipate all the charge off. Larger VFDs will take a longer time to
dissipate charge.
2.1.2.1
Main Power Terminals: R(L1), S(L2), T(L3)
Connect the main power terminals (R(L1), S(L2) and T(L3)) to the power supply through an
electromagnetic contactor or an earth-leakage breaker. These devices isolate the utility power
supply from the VFD and prevent the spread of damage.
This unit is designed to be used on a three-phase power supply. If using on a single phase
power supply, please contact WorldWide Electric for proper sizing.
Do not operate under the following conditions.
-
Unbalanced power supply voltage more than 3%
-
Power supply capacity more than 10 times of the capacity of inverter and case beyond
600kVA.
4000
Power Supply
Capacity (kVA)
600
0
60
400
Power Supply Hamonics
Reactor Required
Drive Capacity (kVA)
Reactor
Unnecessary
-
Turning on/off the power supply more than three times in one minute. Could possibly
damage the precharge circuit of the VFD.
2.1.2.2
Inverter Output Terminals: U(T1), V(T2), W(T3)
Make sure to use a heavier gauge wire when you have long motor leads. This will help to
reduce the voltage drop.
Do not install power factor correction capacitors or a surge absorber to the output of the VFD.
The VFD will trip or sustain damage to the output transistors.
If the motor cable length is more than 65 feet, it is possible that a surge voltage will be
generated and may damage the motor. This is due to phenomena called “Reflective Wave”.
Install a dv/dt filter in front of the motor to protect it.
In the case of two or more motors on the output of an inverter, install an independent overload
protection device for each motor. Set the rated current value of the overload device to 1.1 times
the motor rated current.