
GE Energy Motors GEEP-427-I Copyright 2009, The General Electric Company, USA
16
GEEP-427-I Pegasus, Horizontal Induction Motor
TEWAC, Sleeve Bearing
Insulation resistance
WARNING: BEFORE MEASURING
INSULATION RESISTANCE, THE MACHINE
MUST BE AT STANDSTILL AND ALL
WINDINGS BEING TESTED MUST BE
CONNECTED TO THE FRAME AND TO
GROUND FOR A TIME TO REMOVE ALL
RESIDUAL ELECTROSTATIC CHARGE.
GROUND SURGE CAPACITORS, IF
FURNISHED, BEFORE DISCONNECTING AND
ISOLATE FROM LEADS BEFORE
MEGGERING.
FAILURE TO OBSERVE THESE PRECAUTIONS
MAY RESULT IN INJURY TO PERSONNEL.
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
Fig. 1. Temperature correction factor curve
Summary of Contents for Pegasus MHV GEEP-427-I
Page 46: ...GE Energy Motors 46 ...