GE Custom 8000 Instructions Manual page 14

DLCGEEP-124-I/000, Approved, 2016-11-11, CampinasDM
Insulation resistance
WARNING: BEFORE
INSULATION RESISTANCE, THE MACHINE
MUST BE AT
WINDINGS BEING
CONNECTED TO
GROUND FOR A TIME TO REMOVE ALL
RESIDUAL ELECTROSTATIC CHARGE.
GROUND SURGE
FURNISHED, BEFORE DISCONNECTING AND
ISOLATE FROM
MEGGERING.
FAILURE TO
PRECAUTIONS MAY RESULT IN INJURY TO
PERSONNEL.
14 GE Industrial Control Systems GEEP-124-I
MEASURING
STANDSTILL AND ALL
TESTED MUST BE
THE FRAME AND TO
CAPACITORS, IF
LEADS BEFORE
OBSERVE THESE
Fig. 1. Temperature correction factor curve
GEEP-124-I Horizontal Induction Motor
Insulation resistance is determined by applying a dc
voltage, typically 500 or 1000 Volts, across insulation,
measuring the current flow after the voltage has been
applied for a specific length of time and then
determining the ratio of voltage to current. Because the
current flow is low, the value of insulation resistance
will be great in terms of ohms. Accordingly, megohms
are used as a practical unit.
Factors affecting insulation resistance are as
follows:
1. Moisture
2. Surface cleanliness of the insulation
3. Temperature
4. Length of time of applying the dc test voltage
5. Magnitude of the applied dc test voltage
Copyright 1997,1998 The General Electric Company, USA
WPI, Antifriction Bearing