Operation Of 3 Phase Drives From A Single Phase; Operation With Dc Power Supply Or Common Dc; Motor Connection - Emerson PACMotion VFD Series User Manual

Input Choke
An optional Input Choke is recommended to be installed in the supply line for drives where any of the
following conditions occur:
• The incoming supply impedance is low or the fault level / short circuit current is high.
NOTE For IP20 Frame Size 8 the input current level will vary according to supply impedance. At minimum a
1% line choke must be installed. Installing a 4% line choke further helps towards minimising harmonic current
distortion and total current levels. 1% and 4% line chokes are available.
• The supply is prone to dips or brown outs.
• An unbalanced supply system is used (3 phase drives) where the voltage levels during on load operation
exceed the designed 3% capacity of the PACMotion VFD.
• The power supply to the drive is via a busbar and brush gear system (typically overhead Cranes).
In all other installations, an input choke is recommended to ensure protection of the drive against power
supply faults.
Operation of 3 Phase drives from a Single Phase Supply
A special function of PACMotion VFD allows all drives designed for operation on 3 phase supplies to be
operated on a single phase supply of the correct rated voltage at up to 50% of the nominal capacity.
For Example, Model Number ODP-2-64450-3KA4N can be operated on a single phase supply, 380 – 480 volts,
with the maximum output current limited to 45 Amps.
The supply must be connected to the L1 and L2 terminals of the drive.
Operation with DC Power Supply or Common DC Bus
PACMotion VFD models provide terminals to directly connect to the DC Bus for applications which require
this. For further information on using the DC Bus connections, please refer to your Emerson sales Partner.

Motor Connection

• The drive inherently produces fast switching of the output voltage (PWM) to the motor compared with
operation of the motor directly from the mains supply. Most modern industrial motors are wound for
operation with a variable speed drive and will have insulation rated accordingly. However, on some
motors the quality of insulation may be insufficient or unknown. In such cases the motor manufacturer
should be consulted and preventative measures may be required prior to operating with the drive.
• The motor should be connected to the PACMotion VFD U, V, and W terminals using a suitable 3 or 4 core
cable. Where a 3 core cable is utilised, with the shield operating as an earth conductor, the shield must
have a cross sectional area at least equal to the phase conductors when they are made from the same
material. Where a 4 core cable is utilised, the earth conductor must be of at least equal cross sectional
area and manufactured from the same material as the phase conductors.
• Automatic switchgear should not be installed between the drive output and the motor, opening and
closing contacts in this circuit whilst the drive is energised will inevitably reduce the lifetime of the drive
and could cause product failure. If an isolator is required to be placed between the drive and the motor in
order to comply with local regulations, the device must not be operated when the drive is running.
• For compliance with the European EMC directive, a suitable screened (shielded) cable should be used.
Braided or twisted type screened cable where the screen covers at least 85% of the cable surface area,
designed with low impedance to HF signals are recommended as a minimum. Installation within a
suitable steel or copper tube is generally also acceptable.
The motor earth must be connected to one of the PACMotion VFD earth terminals to provide a low
impedance path for common mode leakage current to return to the drive. This is best achieved in practice by
using a cable with suitable shielding which provides a low impedance path at high frequencies, and ensuring
correct, low impedance earth bonding of the motor cable at both ends. For further information, refer to
page 34.
GFK-3111A PACMotion VFD AC Variable Speed Drive User Guide 27