GE Pegasus MHV GEEP-427-I User manual

GEEP- 427-I
These Instructions do not purport to cover all details or variations in equipment nor to provide for every possible contingency to be met in connection with
installation, operation or maintenance. Should further information be desired or should particular problems arise which are not covered sufficiently for the
purchaser’s purposes, the matter should be referred to GE Energy Motors.
Pegasus MHV®is a registered trademark of General Electric Company.
GE Energy Motors GEEP-427-I Copyright 2009 The General Electric Company, USA 1
Instructions
Pegasus MHV®
Horizontal
Induction Motor
Totally Enclosed Water-to-Air Cooled
Sleeve Bearing

GE Energy Motors GEEP-427-I Copyright 2009, The General Electric Company, USA
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GEEP-427-I Pegasus, Horizontal Induction Motor
TEWAC, Sleeve Bearing
INDEX
Subject Page
Introduction 3
Receiving Handling and Storage 5
Installation 7
Alignment and Coupling 9
Wiring and Grounding 12
Operation 14
Maintenance - General 20
Maintenance - Lube Oil Recommendation 24
Maintenance - Drive-End Bearing 26
Maintenance - Opposite Drive-End Bearing 27
Operational Difficulties 28
Spare Parts 33
Belt and Chain Drives 35
Machine Description 36
Machine Assembly 37
Maintenance - Top Cover and Heat Exchanger 39
Air-to-Water Heat Exchanger 41
Parts Identification 42

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GEEP-427-I Pegasus, Horizontal Induction Motor
TEWAC, Sleeve Bearing
Introduction
General
The purpose of this instruction manual is to
provide a description of the product and to provide
helpful suggestions for receiving, handling, storing,
installing, operating, and maintaining the unit together
with useful general information. Although reasonable
care has been taken in the preparation of this instruction
manual to assure its technical accuracy, no responsibility
is assured in any manner by the General Electric
Company for any consequences of its use. If further
information is required, contact the nearest General
Electric office.
This instruction manual should be available to all
personnel involved in installing and operating the unit. It
should be reviewed before initiating any action on the
unit.
Safety Precautions and Warnings
For equipment covered by this instruction manual,
it is important to observe safety precautions to protect
personnel from possible injury. Among the many
considerations, personnel should be instructed to:
• avoid contact with energized circuits or rotating parts.
• avoid by-passing or rendering inoperative any
safeguards or protection devices.
• avoid extended exposure in close proximity to
machinery with high noise levels.
• use proper care and procedures in handling, lifting,
installing, operating, and maintaining the equipment.
• before operating, replace any covers that have been
removed for inspection.
Safe maintenance practices with qualified
personnel are imperative. Before starting maintenance
procedures, be positive that:
• equipment connected to the shaft will not cause
mechanical rotation.
• main machine windings and all accessory devices
associated with the work the area are de-energized
and will remain disconnected from electrical power
sources for the duration of the maintenance period.
If high potential insulation testing is required,
procedure and precautions outlined in NEMA Standards
MG-1 and MG-2 should be followed.
Failure to properly ground the frame of this
machine can cause serious injury to personnel.
Grounding should be in accordance with the National
Electrical Code and consistent with sound local practice.
WARNING: HIGH VOLTAGE AND ROTATING
PARTS CAN CAUSE SERIOUS INJURY. THE
USE OF ELECTRICAL MACHINERY, LIKE ALL
OTHER UTILIZATION OF CONCENTRATED
POWER AND ROTATING PARTS, CAN BE
HAZARDOUS. INSTALLATION, OPERATION,
AND MAINTENANCE OF ELECTRICAL
MACHINERY SHOULD BE PERFORMED BY
QUALIFIED PERSONNEL. FAMILIARIZATION
WITH NEMA PUBLICATION MG-2, SAFETY
STANDARD FOR CONSTRUCTION AND
GUIDE FOR SELECTION, INSTALLATION AND
USE OF ELECTRIC MOTORS AND
GENERATORS, THE NATIONAL ELECTRICAL
CODE, AND SOUND LOCAL PRACTICES IS
RECOMMENDED.

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GEEP-427-I Pegasus, Horizontal Induction Motor
TEWAC, Sleeve Bearing
Reference Publications and
Standards
ANSI/NEMA MG-2 Safety Standards for construction
and Guide for Selection,
installation and Use of Electric
Motors and Generators.
ANSI C50.10 General Requirements for
Synchronous Machines.
IEEE 1 General Principles for
Temperature Limits in Rating of
Electrical Equipment.
IEEE 85 Test Procedure for Air-borne
Noise Measurements on Rotating
Machinery.
IEEE 112 Test Procedure for Polyphase
Induction Motors and Generators.
IEEE 115 Test Procedures for Synchronous
Machines.
Standards can be obtained by writing to the following:
National Electrical Manufacturers Association
2101 Street, N.W.
Washington, DC 20037
American National Standards Institute
1430 Broadway
New York, NY 10018
Attention: Sales Department
The Institute of Electrical and Electronics Engineers,
Inc.
445 Hoes Lane
Piscataway, NJ 08854
Attention: Publication Sales
Warranty considerations
The warranty coverage applicable to the
equipment specified under “Identification of Unit” may
be found in the corresponding sales contract.
The equipment must be operated in accordance
with nameplate specifications, applicable standards and
codes, and in accordance with this instruction manual for
the warranty to remain in effect during the warranty
period.
If a question or circumstance not covered by the
instruction manual occurs, or should a problem occur,
contact the nearest General Electric Technical Service
representative.

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GEEP-427-I Pegasus, Horizontal Induction Motor
TEWAC, Sleeve Bearing
Receiving, Handling, and Storage
Receiving
Whenever traffic clearance allows, the machine is
shipped from the factory as an assembled unit ready for
installation. Sole plates (or slide rails), if ordered, are
bolted to machine feet. Occasionally some accessory
items are shipped separately. All packing lists should be
carefully checked to assure all items have been received,
Each unit should be carefully inspected upon arrival.
Any damage should be photographed, documented and
then reported immediately to the carrier and to the
nearest General Electric office.
Handling
The machine should be lifted by means of the
lifting lugs. On the 2 or 4 Pole there are 2 lifting lugs
positioned on the top of the cooler (see Fig. 1). On the 6
Pole, there are 4 lifting lugs positioned on the frame (see
Fig. 2). If couplings or other attachments unbalance the
load, an additional sling should be used to prevent
tipping or rotation.
In all cases spreaders should be used. For the 6
Pole, the spreaders are important to prevent damage to
the top cover while lifting the machine. For the 2 and 4
Pole, if the spreaders cannot be used, the slings should
not make an angle smaller than 60° with the horizontal to
prevent over stress on the slings and the studs.
WARNING: LIFTING LUGS ON THE FRAME
ARE DESIGNED FOR LIFTING THE MACHINE
ONLY. DO NOT USE FOR LIFTING COUPLED
EQUIPMENT SUCH AS PUMPS,
COMPRESSORS, GEARS OR OTHER
EQUIPMENT. DO NOT USE MACHINE
LIFTING LUGS FOR LIFTING EQUIPMENT
ON A COMMON BASE.LIFT THE ASSEMBLY
WITH A SLING AROUND THE BASE OR BY
OTHER LIFTING MEANS PROVIDED ON THE
BASE. FOR UNBALANCED LOADS (SUCH AS
COUPLINGS OR OTHER ATTACHMENTS),
ADDITIONAL SLINGS OR OTHER EFFECTIVE
MEANS SHOULD BE USED TO PREVENT
TIPPING.
FAILURE TO OBSERVE THESE PRECAUTIONS
MAY RESULT IN DAMAGE TO THE
EQUIPMENT, INJURY TO PERSONNEL, OR
BOTH.

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Always lift or move the unit with all assembly
bolts, screws and studs in place, secured with the shaft
clamp in position when supplied (supplied on machines
with sleeve bearings only). Machines with oil-lubricated
bearings are shipped without oil.
Storage
If, at the time of purchase, it was specified that the
motor be packaged for long-term storage, the package
should be left intact during the period of storage.
If the machine is not put in service immediately,
adequate precautions must be taken to protect it while in
storage. The following instructions are provided as a
guide for storage. Full compliance with these instructions
is required to maintain the warranty.
During manufacturing, testing, and preparation
for shipment basic precautions are taken by the factory to
guard against corrosion of the bearing journals and shaft
extension. The shaft extension is treated with a heavy
coating of rust inhibitor. All machines with oil-lubricated
bearings are operated and tested at the factory with a
rust-inhibiting oil in the lubrication system. Although the
machines are shipped without oil , a rust-inhibiting film
remains on the critical bearing surfaces during transit and
for up to three months of normal storage. Nevertheless ,
when the machine is received, the bearing oil reservoirs
should be filled to the proper oil level with a good grade
of rust-inhibiting oil. (See section entitled Lube Oil
Recommendation on page 24).
Grease-lubricated machines have the bearings
packed at the factory and no further preventive
maintenance is required on the bearings during storage.
For clean, dry, indoor storage locations, rotate the
shaft of all two-bearing machines at three-month
intervals so as to thoroughly coat journals with a fresh oil
film or change the rolling element under load.
Machines equipped with brushes should have the
brushes lifted in the brush holders so they are not in
contact with the collectors.
Outdoor storage is not recommended. Aside
from all the possibilities of external weather conditions,
erection conditions, environmental conditions etc., which
can affect an idle machine, variations in temperature and
humidity can cause condensation throughout the unit,
producing rust and corrosion on metal parts as well as
deterioration of the electrical insulation. If outdoor
storage cannot be avoided, contact the factory through
the nearest General Electric office giving full
information on the circumstances and explaining steps to
be taken to protect the machine. Failure to protect the
machine may invalidate the warranty.
The storage facility must provide protection from
contact with rain, hail, snow, blowing sand or dirt,
accumulations of ground water, corrosive fumes and
infestation by vermin or insects. Continuous or severe
intermittent floor vibration should be avoided. Electrical
service for space heater and illumination should be
provided. There should be fire detection and a fire
fighting plan. The machines must not be stored where
they are liable to accidental damage or exposed to weld
spatter, exhaust fumes or dirt. If necessary, erect suitable
guards or separating walls to provide adequate
protection. Avoid storage in a atmosphere containing
corrosive gases, particularly chlorine, sulphur dioxide
and nitrous oxides.
The machine in storage must be protected from
moisture condensation on the windings and other critical
parts. To prevent condensation, energize the machine’s
space heaters to keep the machine temperature above the
room temperature by at least 3C. During the periods of
extreme cold or rapid temperature decrease, the space
heaters may not be adequate to maintain this temperature
differential. Therefore, safe supplementary space heating
may be required.

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The machine in storage should be inspected
periodically and inspection records maintained. The
following tests and inspections are designed to reveal
deterioration or failure of protective systems (shelter,
coatings and temperature control), of the machine
without delay. Inspect the storage area for compliance to
the above criteria and inspect the stored machine for the
following:
1. Physical damage.
2. Cleanliness.
3. Signs of condensation.
4. Integrity of protective coatings.
5. Condition of paint - discoloration.
6. Signs of vermin or insect activity.
7. Satisfactory space heater operation. It is
recommended that an alarm system be in place to operate
on interruption of power to the space heaters. Alarms
should be responded to immediately.
8. Record the ambient temperature and relative
humidity adjacent to the machine, the winding
temperature (utilizing the RTD’s), the insulation
resistance and the polarization index. Refer to the section
entitled Insulation Resistance on page 15 for information
on determining the insulation resistance and polarization
index.
Experience has shown that adequate precautions
during storage will avoid costly deterioration of parts and
lengthy maintenance procedures at installation and start-
up
.

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TEWAC, Sleeve Bearing
Installation
Location
The location of the connected equipment
determines the general location of the machine. Motors
and generators, however require large volumes of clean
air for cooling and these machines have environment
requirements which must be considered. They are:
1. A clean, well-ventilated location.
2. The machine enclosure should be consistent
with the location, environment and ambient conditions.
3. If the location is not relatively free of dust and
particles, the machine should have air filters or, in more
severe cases, the machine should be enclosed.
4. Other equipment, walls, buildings, etc. should
not restrict machine ventilation or allow ventilating air to
recirculate.
5. Adequate space around the machine for
normal maintenance
6. Adequate overhead space for removal of the
top cover.
7. An environment free of corrosive gases and
liquids (both acids and bases).
WARNING: INSTALLATION OF THE
MACHINE WHERE HAZARDOUS FLAMMABLE
OR COMBUSTIBLE VAPORS AND/OR DUSTS
PRESENT A POSSIBILITY OF EXPLOSION OR
FIRE SHOULD BE IN ACCORDANCE WITH
THE NATIONAL ELECTRICAL CODE,
ARTICLES 500-503, AND CONSISTENT WITH
SOUND LOCAL PRACTICES. EXTREME CARE
IS REQUIRED FOR MACHINES SUPPLIED
WITH A DUST-IGNITION-PROOF
COLLECTOR-RING HOUSING, ACCESSORY
DEVICE, OR CONDUIT BOX SINCE ANY
NICKS OR BURRS DURING DISASSEMBLY
AND REASSEMBLY MAY DESTROY THE
EXPLOSION-PROOF OR DUST-IGNITION-
PROOF FEATURES.
IF IGNITABLE DUST OR LINT IS PRESENT,
THE SURFACE TEMPERATURE OF SPACE
HEATERS, IF SUPPLIED, SHOULD NOT
EXCEED 80 PERCENT OF THE IGNITION
TEMPERATURE. REFER TO FACTORY FOR
INFORMATION ON SURFACE
TEMPERATURE. DUST AND/OR LINT
SHOULD NOT BE ALLOWED TO BUILD UP
AROUND THE SURFACE OF THE SPACE
HEATERS.
FAILURE TO OBSERVE THESE PRECAUTIONS
MAY RESULT IN DAMAGE TO EQUIPMENT,
INJURY TO PERSONNEL, OR BOTH.
Foundation
The mounting dimensions of the machine and the
minimum foundation stiffness required to adequately
support the machine are supplied on the outline. A
certified outline drawing is supplied by the factory soon
after receipt of the order, and the above information is
essential for planning and constructing the foundation.
A properly constructed foundation is essential to
insure the correct horizontal and vertical alignment of the
driving and the driven equipment, to carry the weight, to
resist the reaction torque, to absorb any cyclical or
dynamical forces generated by the driven equipment and
to prevent vibration amplification. Since a suitable
foundation is a basic requirement for satisfactory
operation, it is recommended that a person technically
competent in foundation design be consulted.
Although adequacy of the foundation is the
responsibility of the owner, the following suggestions are
provided as a guide. A concrete foundation is preferable
to any other type of foundation. It should be reinforced
as required and should extend downward to have a firm
footing. The top of the foundation should be
approximately one inch short of the bottom allow for
grout. If the machine must be located on structural steel
or on a building floor, the weight and minimum stiffness
requirements stated on the outline drawing must be met.
Also, the dynamics of the entire structural system from
the machine to the structure footing must be considered.
Mounting
The machine has two full-length mounting feet,
one on each side, consisting of machined steel bars

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TEWAC, Sleeve Bearing
integral with the frame. When foundation caps or sole
plates are used, their function is to act as spacers between
the actual foundation and the unit. They are to be a part
of the foundation. Accordingly, if they are used, it is
important that they be firmly attached to the foundation
to withstand the applied torques and normal vibration
forces. It is also imperative that they be supported evenly
on the foundation and be located in a level plane.
Place the machine on the foundation (sole plates,
if used) with its shaft approximately in line with and at
proper distance from the shaft of the machine to be
coupled. Use shims under the feet to adjust for the
correct shaft height. Refer to the outline drawing for
information covering the shim location and required
shim and depth. When this preliminary alignment is
complete, install the holdown bolts but do not tight them
until final alignment has been made.

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GEEP-427-I Pegasus, Horizontal Induction Motor
TEWAC, Sleeve Bearing
Alignment and Coupling
General
Machines with sleeve bearings are adjusted at
the factory to have approximately 1/2-inch total end play
(4-pole generators have 3/4-inch total end play), with
approximately 1/4-inch end play either way from
magnetic center. The magnetic center and end play limits
are marked on the shaft by a series of three dots. The
rotor will run on magnetic center with approximately
1/4-inch end play in either direction. Sleeve bearings are
not designed to carry any external load thrust.
Accordingly, limited end-float couplings are
recommended for all units with sleeve bearings.
A limited end-float coupling permits relative but
controlled axial movement between the adjacent ends of
two shafts. This movement should be limited (value of
2xC in the table and Fig. 1. below) to be less than the
axial clearance of the AC Machine bearing (value of A +
B in Fig. 1. below), so that the limited, end-float
coupling performs its function. When the correct
alignment is implemented, the coupling prevents the
shaft shoulders on the inboard end of each journal from
exerting thrust on the corresponding bearing. The
recommended clearances in inches for limited, end-float
couplings are given in table 1.
Table 1 Recommended clearances
Fig. 1. Shaft arrangement for limited end-float coupling
Parallel and Angular Alignment for
Flexible Couplings
SHAFT POSITION MACHINE END PLAY __A__ __B__ __C__
Shaft ends together 1/2 5/32 11/32 3/32
Shaft ends apart 1/2 11/32 5/32 0
Shaft ends together 3/4 5/16 7/16 3/16
Shaft ends apart 3/4 7/16 5/16 0

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Fig. 2. Arrangement of indicator for parallel alignment Fig. 3. Arrangement of indicators for angular alignment
Flexible couplings should not be used to
compensate for inadequate initial alignment of the two
coupling halves. Refer to the instructions supplied by the
flexible coupling manufacturer. Coupling parts, such as
pins, links, buffers, and spacers should be removed
(depending on the type of coupling) and the sleeves
should be axially moved over the shaft to expose the
active hub portions of the coupling halves. The spacing
between coupling hubs should be that recommended by
the coupling manufacturer.
The parallel and angular alignment of the two
coupling halves may be accomplished using the
procedures outlined below, provided the procedures do
not conflict with requirements supplied by the coupling
manufacturer. If a machined, vertical surface is not
accessible on one or both coupling halves, feeler or block
gauges may be substituted for the two dial indicators in
performing the angular alignment check. The two
coupling halves should be aligned to within 0.001-inch
parallel and 0.0015-inch angular misalignment. After the
flexible coupling halves are aligned, the coupling should
be lubricated and assembled in accordance with the
coupling manufacturer’s instructions.
Parallel Alignment for Flexible
Couplings
Position the motor or generator on the foundation
with the plane of its feet horizontal as discussed
previously under Mounting. Then, axially position the
rotor in its magnetic center using the pick punch marks
on the drive end. Axially position the motor with respect
to the machine as discussed in the section entitled
“GENERAL” in the publication. Attach a dial indicator
on one coupling hub with the indicating button on the
machined, circumferential surface of the other coupling
hub. See Fig. 2.
Set the dial indicator zero. Mark the location of
the indicating button with a visible mark. Rotate each of
the two shafts in 90 degree increments, and successively
read and record the dial indications when the indicator is
at 3:00, 6:00, 9:00 and 12:00 o’clock angular positions.
The indicating button must be positioned on the mark for
each reading.
Adjust the shaft position such that the difference
between the two side readings (3:00 and 9:00 o’clock)
and between the top and bottom readings (12:00 and 6:00
o’clock) is less that 0.001-inch. This may require several
iterations. Lateral (3:00 and 9:00 o’clock) differences are
corrected by lateral movement of the unit. Vertical
(12:00 and 6:00 o’clock) differences are corrected by
appropriately adding or removing mounting shims. The
proper shim location is shown on the outline drawing.
Note that the total number of shims in a given shim pack
under any one foot should not exceed five, because too
many shims may provide a “soft” mount on that foot.
This condition could cause dynamic problems.
Drilled and tapped holes are provide in the motor
or generator feet for jacking screws as a convenience in
alignment. Note that jacking screws must not be used for
permanent support.
Angular Alignment for Flexible
Couplings
Axially separate the coupling halves to their
maximum end float. Attach a dial indicator on one
coupling hub with the indicating button positioned
against vertical, machined surface on the other coupling
hub. Attach a second indicator hub 180 degrees apart.
See Fig. 3. Mark the locations of the indicating button
with a visible mark.

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Set the two dial indicators to zero. Then, with
each coupling at full end float, rotate the two coupling
halves in 90 degree increments. Read and record each
dial indicator at 3:00, 6:00, 9:00 and 12:00 o’clock
angular positions of the shaft. Two dial indicator setups,
180 degrees apart, are used to correct for possible, axial
shift of one shaft with respect to the other. Use the
difference in readings between the two indicators to
determine the angular misalignment between the two
coupling halves. Add or remove shims under the feet as
appropriate to correct for misalignment in the vertical
plane. A lateral, angular movement of the unit is required
to correct for misalignment in the horizontal plane.
Continue the angular alignment procedure until the
angular misalignment does not exceed 0.0015-inch. This
may require several iterations.

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Wiring and Grounding
WARNING: MOTOR AND CONTROL WIRING,
OVERLOAD PROTECTION AND GROUNDING
SHOULD BE IN ACCORDANCE WITH THE
NATIONAL ELECTRICAL CODE AND
CONSISTENT WITH SOUND LOCAL
PRACTICES.
FAILURE TO OBSERVE THESE CAUTIONS
MAY RESULT IN DAMAGE TO THE
EQUIPMENT, INJURY TO PERSONNEL, OR
BOTH.
Power connections
The stator winding is terminated in the power
terminal box. Connections to the stator wiring should be
made in accordance with the stator connection diagram
for the machine or with the connection diagram shown
on the main nameplate. The stator is wound to produce
clockwise rotation, facing opposite drive and when the
phase sequence of the applied voltage is T1, T2, and T3
(i.e. when the phases of the supply voltage connected to
the power leads reach positive maximum in that time
order.). The direction of rotation can be changed by
reversing any two of the connections. However, the
machine should always rotate in the direction shown on
the nameplate. Machines Furnished with a single
direction of rotation have an arrow on the drive end. If
the owner desires to operate the motor in opposite
standard rotation, first check the factory for suitability
through the nearest General Electric office.
Before any electrical connections are made
between the machine and the owner’s power or accessory
cable or wire, it is desirable to check the insulation
resistance of the winding to determine if the winding is
sufficiently dry for safe operation. See the section
entitled Insulation Resistance on page 14. This check
may prevent having to break the electrical connections
later. The stator winding leads are terminated with
connectors for bolting to corresponding connectors on
the cable from the owner’s power supply. The bolted
connections should be adequately insulated, phase-to-
phase and to ground.
Accessory connections
Depending upon the specific equipment
furnished, (see outline nameplate) the machine may
include any of the following accessories:
• Stator winding resistance temperature
detectors, 2 per phase
• Bearing resistance temperature detectors.
• Copper-constantan bearing thermocouples
• Bearing temperature readout capability
• Bearing temperature alarm and shutdown
contact capability
• Space heaters, with either 220C or 120C
maximum surface temperature
• Stator winding thermostat
• Heaters for the bearing oil reservoir. Switch
for excess pressure drop across air filters
• Proximity type vibration pickup for shaft
vibration with or without proximeters (sleeve
bearings only)
• Velocity vibration pickup for end shield
vibration (antifriction bearings only) with
alarm light and contacts
When supplied, all of the above accessories will
have electrical terminations in the accessory terminal
box, except for the seismic vibration pickup which has its
electrical termination for the contacts at the device
located on the endshield.
For all of the accessories that have electrical
terminations in the accessory terminal box, a Schematic
Diagram and an Accessory Lead Connection Diagram
will be provided on the inside of the accessory terminal
box cover. This gasketed cover should be kept closed to
prevent the entrance of moisture, dust and conducting
particles. The gasketed cover should be kept closed to

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prevent the entrance of moisture, dust, and conducting
particules. The gasketed cover should also be closed for
electrical safety, except when required to perform
connection work inside the box.
Grounding
Two stainless-steel, grounding pads are supplied
on the frame. One at each end near the foot. A pair of
drilled and tapped holes, with NEMA spacing and size
1/2-13, are provided in each grounding pad. One
additional stainless-steel, grounding pads are supplied
inside the power terminal box in the region of the throat
connection between the power terminal box and the
frame. These pads are used for connection of ground
leads, cable shield, etc., as may be required. These
grounding pads are also drilled and tapped as described
above. The machine should be grounded in accordance
with the National Electric and consistent with sound
local practices.

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Operation
Operating Voltage and Frequency
Variations of applied stator voltage and frequency
from the rated nameplate values will result variation of
machine performance. Torque, efficiency, power factor,
heating and stator current will change. Also, noise and
vibration levels may change. The torque varies as the
square of the voltage; therefore, a 10 percent decrease in
voltage will decrease the torque by 19 percent. For best
operating performance, nameplate voltage and frequency
should be maintained.
The machine will operate successfully, under
running conditions and at rated load. with variations in
voltage or frequency up to the limits indicated below:
1. Plus or minus 10 percent of rated voltage, at
rated frequency.
2. Plus or minus 5 percent of rated frequency, at
rated voltage.
3. A combination of variation in voltage and
frequency of 10 percent (sum of the absolute quantities)
of the rated values, provided that the variation in
frequency does not exceed plus or minus 5 percent of its
rated value.
Performance of the machine within these voltage
and frequency variations will not be in accordance with
the values established for operation at rated nameplate
voltage and frequency.
Line-to-line Voltage Balance
Polyphase machines are sensitive to unbalance in
the applied line voltages. If unbalances exist in the
applied line voltage, unbalance in phase currents will
result. The resulting unbalance in currents will, in
general, be significant. For example, the locked-rotor
current will be unbalanced by the same percentage as the
voltage, but at operating speed the percentage unbalance
of the current will be 6 to 10 times the percent unbalance
of the voltage. Percent Voltage Unbalance is defined as
follows:
Percent
Voltage = x 100
Unbalance
Where Average Voltage is arithmetic average of
the three line voltages and Maximum Voltage Derivation
is the greatest line voltage deviation from the average.
Unbalanced line voltages result the production of
negative sequence currents in the machine that produce
fields which rotate in a direction counter to the normal
field. This results in an increase in current, losses and
heating with reduction in torque, efficiency and power
factor. Accordingly, line voltages should be as closely
balanced as can be determined on a voltmeter.
If line voltage unbalance exists, the machine
may be damaged and should be derated in accordance
with Figure 20-2 of NEMA Standard MG-20.55, in order
to reduce the possibility of such damage. Derating
factors, for several values of line voltage unbalance, are
given below.
Percent Voltage Unbalance 1 2 3 4 5
Operating Factor 0.99 0.95 0.89 0.82 0.75
In addition, the selection and setting of the
machine overload-protective device must consider the
derating factor and the increase in current, resulting from
line voltage unbalance. This is a difficult procedure
which must be done by a person familiar with setting
protective devices to adequately protect the machine. It is
recommend that the nearest General Electric office be
contacted if assistance is required.
Maximum Voltage Derivation
Average Voltage

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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

GE Energy Motors GEEP-427-I Copyright 2009, The General Electric Company, USA 17
GEEP-427-I Pegasus, Horizontal Induction Motor
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The magnitude of the applied dc test voltage
only slightly affects the value of the insulation resistance
and the use of a 500 Volt or 1000 Volt megger for stator
windings (and a 500 Volt megger for rotor windings) is
suitable for machines covered by this Instruction Manual.
The environmental conditions of moisture and surface
cleanliness, together with the ambient temperature,
largely determine the value of insulation resistance. The
insulation must be clean and dry and the measured value
must be corrected to 40C. This value is then compared to
a minimum acceptance criteria. Moisture and dirt will
decrease the insulation resistance of a winding and these
conditions must be corrected in order to increase it.
The insulation resistance of a winding measured
by a 500 Volt or a 1000 Volt megger, with the test
applied for 1 minute, should not be less than.
R = KV + 1
where : R = Insulation Resistance in megahoms,
corrected to 40C base
KV = rated voltage of the winding in kilovolts
To convert the actual insulation resistance reading
of the megger, Rt, taken at an ambient winding
temperature in degree Celsius, to R, make the following
conversion.
R = KtRt
The temperature correction factor, Kt, can be
determined for any specific winding or a reasonable
approximation can be used. Both methods will be
described.
To determine the temperature correction factor for
a specific winding, make several measurements (at least
five) at several different temperatures, all of which are
above the dew point. Then plot the results, with
measured insulation resistance on a log scale and
winding temperature on a linear scale. The results should
approximate a straight line, from which the value of
insulation resistance at 40C can be determined.
A more general method, with reasonable
accuracy, is to use the curve, Fig. 1, to determine Ktas a
function of the winding temperature at the time of
measurement. It is based on doubling the insulation
resistance for each 10C reduction in temperature, for
conditions above the dew point. It has been found to be
reasonable for new windings.
The polarization index is frequently helpful in
evaluating the cleanliness and freedom from moisture of
a winding. The polarization index is a measure of the
change is insulation resistance with the time duration for
which the test is applied. It is conducted by applying the
megger for 10 minutes and determining the insulation
resistance at 1 minute and 10 minutes. The polarization
index in the ratio of the 10-minute insulation resistance
reading to the 1-minute insulation resistance reading,
both readings haven been corrected to a 10C temperature
base. Clean, dry windings should exhibit a polarization
index of 2 or more.
Each winding of each unit will have its own
insulation resistance history which is unique to it. It is
recommended that the insulation resistance be measured
and recorded at least every six months, and more often if
feasible, and that the polarization index be measured and
recorded at least once a year. This accumulated
information will provide a data base which will be
helpful in managing preventative maintenance.
The user is referred to IEEE Standard 43, IEEE
Recommended Practices for Testing Insulation
Resistance of Rotating Machinery, for a more complete
discussion of the complete subject of Insulation
Resistance.
Pre-start inspection
Before the machine is started for the first time, a
pre-start inspection should be made. The following are
some of the items frequently overlooked.
1. Measure the insulation resistance of the
windings. For machines located in or near salt air or
other corrosive environments, a polarization index
should also be taken.
2. Verify that the voltage and frequency
corresponds to the nameplate.
3. Verify that the phase sequence of the applied
voltage is correct for the desired direction of rotation.
Verify that the desired direction of rotation agrees with
the nameplate.
4. For totally-enclosed. water-cooled machines,
verify that the cooling-water temperature does not
exceed the value on the nameplate.
5. The lubricant used should agree with the
nameplate and this instruction book.

GE Energy Motors GEEP-427-I Copyright 2009, The General Electric Company, USA
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6. Verify that the bearing housings on machines with
self-lubricated bearings have been filled to the proper
level.
7. The oil flow to each bearing housing on flood or
forced lubricated machines should be adjusted so the oil
level in each bearing housing is maintained.
8. All accessory devices should be connected and
operational.
9. All protective and control equipment should be
installed and operational.
10.The machine hold down bolts should be tightened
and the foot doweling completed.
11.The coupling alignment should be in accordance with
previous instructions.
12.The interior of the motor frame, top cover, terminal
boxes and fan casings (for Totally-enclosed Air-to-Air
Cooled Machines) should be free of tool, waste and other
foreign materials.
13.The air gap of the machine should be free of foreign
material.
14.Guards should be in position to protect personnel
from moving parts such as coupling, etc.
15.Walls, baffles, other equipment, coupling guards,
etc., should not obstruct the necessary movement of air
required to adequately ventilate the machine.
16.Any load condition of the drives equipment which
contributes its load torque, at low speed, should be set
compatible with the starting torque specified for the
motor (i.e., if it is necessary to start the driven equipment
in an unloaded condition, in order to correspond to the
starting torque specified for the motor, then verify that
the driven equipment is appropriately unloaded).
17. All covers should be in place and properly secured.
The cover on the power terminal box and the accessory
terminal box should be properly secured.
Initial test run
The starting current of a motor is several times the
rated current. This starting current causes the windings to
heat at a much higher rate than normal and causes the
windings to heat at a much higher rate than normal and
causes magnetic forces on the end turns to be many times
normal. The section of this publication entitled
“Frequency of Starts and Load Inertia” should be read,
since the user may also be considering checkout and
adjustment of some of the control and protection
equipment at this time. The limitations on starting
must be observed at all times to prevent damage to
the machine.
After verifying that the machine and the rest of
the system is ready for operation, a controlled initial start
should be made and a test run performed to verify that
the unit is properly installed and is operational. For this
run, it is recommended that several people be
appropriately located in order to observe any problems.
The following are the minimum steps to be taken on the
initial test run. Note that the machine must be shut
down immediately if any problem occurs.
1. If so equipped (See Outline Drawing), start
auxiliary lubrication system and verify oil flows. Also
check interlocking to make sure machine is prevented
from starting unless the lubrication system is functioning
and the machine will be shut down on the loss of
lubrication.
2. Start the machine. (For a generator, bring up
to speed with prime mover.)
3. Listen for any unusual noise during
acceleration and running.
Machines with oil-lubricated bearings only.
4. Observe oil flow and/or oil ring action for
each bearing.
5. Verify that the rotor runs at the magnetic
center.
6. Observe and record each bearing temperature
and the rate at which it is increasing for each bearing.
Initially temperatures will rise rapidly and then should
level off.
NOTE: Bearing temperatures should not
exceed 95C for a sleeve bearing.

GE Energy Motors GEEP-427-I Copyright 2009, The General Electric Company, USA 19
GEEP-427-I Pegasus, Horizontal Induction Motor
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7. Observe the temperature of windings
(Resistance Temperature Detectors (RTD’s) are
provided on all machines). In no case should the
windings exceed the sum of the rated rise on the
nameplate plus the maximum design ambient.
8. Determine that the amplitude of vibration
is not excessive (see the section entitled “Vibration”
in this publication). Misalignment should be the first
item to check if there is unacceptable vibration.
9. Verify that all accessories supplied with
the machine are functioning normally and are
performing consistent with the load on the machine
and system.
10. Verify that all control and protective
devices are functioning normally and are performing
consistent with the load on the machine and system.
11. The machine should be operated and
fully observed for not less than two hours and should
be free of any problems before it is released for
normal duty.
12. As stated earlier, the machine must be
shut down immediately if any problem occurs.
Should any problem occur, it source should be
determined and corrected, and then the initial test run
should be repeated.
Vibration
General Electric motors and generators,
covered by this Instruction Manual, are balanced at
the factory, in accordance with NEMA Standard MG
1-20.52 and MG 1-20.53, to be within the following
limits (unless otherwise specified in the sales
contract).
Table 1 – Bearing Housing Unfiltered Vibration
Limits
Speed
(rpm) Velocit
y
(inches/sec peak)
3600 0.12
1800 0.12
1200 0.12
900 0.12
720 0.072
600 0.064
Vibration amplitude measurements are made on the
bearing housing and are taken in the vertical, horizontal and
axial directions.
Table 2 - Limits for the unfiltered maximum relative
shaft displacement.
Speed
(rpm) Maximum Relative Shaft Displacement (inches peak-to-peak)
1801 - 3600 0.0028
< 1800 0.0035
If the owner’s half coupling was sent to the factory
to be mounted onto the machine shaft extension, the rotor is
balanced with the half coupling installed. Otherwise, the
rotor is balanced with a half key (i.e., the keyway is filled
with a steel bar equal in length to the key length shown on
the outline and flush with the top of the keyway). The shaft
key furnished with the machines of 1500 rpm and higher is a
full-length, full key with a three-inch long half key extension
on one end. To maintain factory balance, cut the key to
length as follows. See Fig. 5.
1. Measure the coupling hub length (H) and cut the
full key to length H by cutting the excess from the
full key end.
2. Cut the half key end so that the overall key length
equals the key length shown on the outline drawing.
3. Full key must fill coupling/keyway. Half key must
fill shaft/keyway.
WARNING: TO AVOID EXCESSIVE STRESSES IN
THE KEY, THE MAXIMUM LENGTH OF THE
HALF KEY SHOULD NOT EXCEED 3.0 INCHES.
FAILURE TO OBSERVE THIS PRECAUTION MAY
RESULT IN DAMAGE TO THE EQUIPMENT,
INJURY TO PERSONNEL, OR BOTH.
The foundation should be constructed in
accordance with the requirements in the section entitled
“Foundation” on page 7. If the unit has been properly
aligned, the amplitude of the vibration of the installed motor
should be as stated in the above table. If vibration
amplitudes are significantly greater than these values, the
instruction referenced above should be reviewed.
Misalignment is the most probable cause of excessive
vibration. Other possible causes are “soft” shim packs under
one or more feet, loose foot bolts or an inadequate
foundation. Contributions to vibration from the driven
equipment should not be overlooked.

GE Energy Motors GEEP-427-I Copyright 2009, The General Electric Company, USA
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GEEP-427-I Pegasus, Horizontal Induction Motor
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Do not operate the machine with excessive
vibration. If the cause cannot be found and corrected,
contact the nearest General Electric office.
Frequency of starts and load
inertia
When a motor starts, it must accelerate the
rotational inertia of its own rotor and that of the
driven equipment from standstill to full speed.
Accordingly, it must transfer and store a larger
amount of energy into the rotating parts in a short
time. An equal amount of energy is dissipated in the
rotor windings in the same short period of time.
During the starting period, current in the
windings are several times the rated value. This
causes heating of the windings at a significantly
greater rate than occurs at full-speed operation. Also,
because magnetic forces are proportional to the
square of the current, forces on the winding end turns
are many times greater than the normal condition.
For the above reasons, the frequency of starts and
the magnitude of rotational inertia of the connected load,
must be limited for squirrel-cage induction and synchronous
motors. The motors covered by this Instruction Book (unless
otherwise stated in the, sales contract), are suitable for
accelerating the rotational inertia of the driven equipment in
accordance with Standard MG 1-21.42. The motors are
suitable for the following frequency of starts.
1.With the motor initially at ambient temperature, two
starts in succession, coasting to rest between starts.
2. With the motor initially at a temperature not
exceeding its rated temperature, one start.
It is recommended that the total number of starts
made in the life of the machine be controlled, with an effort
to minimizing them, since the life of the machine is affected
by the total number of starts.
Wound rotor induction motors have the capability to
accelerate high inertia loads with limited stator current
through the use of external resistance inserted in the rotor
circuit. The motor characteristic is changed by adjusting the
resistance. Most of the energy dissipated in the rotor circuit
during the acceleration is dissipated in the resistor external
to the motor.
Oil level
Sleeve bearing machines are furnished with an oil
level gauge in each bearing housing. Refer to the Parts
Identification Instruction for this model to locate the oil
level gauge. The gauges are either bulls eye type, with a
circular glass window, or column type.
With the bulls eye type gauge, the centerline of the
gauge indicates maximum oil level and the bottom of the
gauge indicates minimum oil level
.