Leakage Current (>3.5 Ma); Grounding Using Shielded Cable; Motor Connection - GE AF-650 GP Design And Installation Manual

Installation
•
Use the clamps provided with on the equipment
for proper ground connections.
•
Do not ground one frequency converter to
another in a "daisy chain" fashion.
•
Keep the ground wire connections as short as
possible.
•
Use of high-strand wire to reduce electrical noise
is recommended.
•
Follow motor manufacturer wiring requirements.
2.5.2.1 Leakage Current (>3.5 mA)
Follow national and local codes regarding protective
earthing of equipment with a leakage current > 3.5 mA.
Frequency converter technology implies high frequency
switching at high power. This generates a leakage current
in the ground connection. A fault current in the frequency
converter at the output power terminals might contain a
DC component which can charge the filter capacitors and
cause a transient ground current. The ground leakage
current depends on various system configurations
including RFI filtering, shielded motor cables, and
frequency converter power.
EN/IEC61800-5-1 (Power Drive System Product Standard)
requires special care if the leakage current exceeds 3.5 mA.
Grounding must be reinforced in one of the following
ways:
•
Ground wire of at least 10 mm
•
Two separate ground wires both complying with
the dimensioning rules.
See EN 60364-5-54 § 543.7 for further information.
Using RCDs
Where residual current devices (RCDs), also known as earth
leakage circuit breakers (ELCBs), are used, comply with the
following:
•
Use RCDs of type B only which are capable of
detecting AC and DC currents.
•
Use RCDs with an inrush delay to prevent faults
due to transient ground currents.
•
Dimension RCDs according to the system configu-
ration and environmental considerations.
MG35M402
AF-650 GP™ Design and Installation Guide

2.5.2.2 Grounding Using Shielded Cable

Grounding clamps are provided for motor wiring (see
Illustration 2.7).
Illustration 2.7 Grounding with Shielded Cable

2.5.3 Motor Connection

INDUCED VOLTAGE!
2
(8 AWG).
Run output motor cables from multiple frequency
converters separately. Induced voltage from output
motor cables run together can charge equipment
capacitors even with the equipment turned off and
locked out. Failure to run output motor cables separately
could result in death or serious injury.
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DET-767c All rights reserved.
WARNING
For maximum wire sizes, see Table 12.1.
Comply with local and national electrical codes
for cable sizes.
Motor wiring knockouts or access panels are
provided at the base of IP21 and higher (Nema 1,
12, and 4/4X Indoor) units.
Do not install power factor correction capacitors
between the frequency converter and the motor.
Do not wire a starting or pole-changing device
between the frequency converter and the motor.
Connect the 3-phase motor wiring to terminals
96 (U), 97 (V), and 98 (W).
Ground the cable in accordance with grounding
instructions provided.
Torque terminals in accordance with the
information provided in chapter 12 Terminal and
Applicable Wire.
Follow motor manufacturer wiring requirements.
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