Installation, Operation
and Maintenance Manual
AC Induction Motors
• 56 - 5000 Frame
Manufactured for Allen-Bradley by Marathon
Electric, Inc.
2 AC Induction Motors
Contents General Information
Acceptance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Installation
Uncrating and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Floor Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
V-Belt Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Direct Connected Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Thermal Protector Information . . . . . . . . . . . . . . . . . . . . . . . 6
Changing Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Reduced Voltage Starting . . . . . . . . . . . . . . . . . . . . . . . . . .7
Operation
Allowable Voltage and Frequency Range . . . . . . . . . . . . . . 8
Cleanliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Condensation Drain Plugs . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Service
Lubrication Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Relubrication Amounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Troubleshooting
Motor Troubleshooting Chart . . . . . . . . . . . . . . . . . . . . . . . 11
Parts Description Diagram . . . . . . . . . . . . . . . . . . . . . . . . .13
General Information Important: These instructions must be followed to ensure safe and
proper installation, operation and maintenance of the
motor. They should be brought to the attention of all
persons who install, operate or maintain this equipment.
Motors are all fully factory tested and inspected before shipping.
Damage during shipment and storage can occur. Motors not correctly
matched to the power supply and/or the load will not operate
properly. These instructions are intended as a guide to identify and
eliminate these problems before they are overlooked or cause further
damage.
Acceptance
Check carefully for any damage that may have occurred in transit. If
any damage or shortage is discovered, do not accept until an
appropriate notation on the freight bill is made. Any damage
discovered after receipt of equipment should be immediately reported
to the carrier.
AC Induction Motors 3
Storage
1. Keep motors clean.
• Store indoors.
• Keep covered to eliminate airborne dust and dirt.
• Cover openings for ventilation, conduit connections, etc.to
prevent entry of rodents, snakes, birds, and insects, etc.
2. Keep motors dry.
• Store in a dry area indoors.
• Temperature swings should be minimal to guard against
condensation.
• Space heaters are recommended to prevent condensation.
• Treat unpainted flanges, shafts, and fittings with a rust
inhibitor.
• Check insulation resistance before putting motor into service.
(Consult manufacturer for guidelines).
3. Keep Bearings Lubricated.
• Once per month, rotate shaft several turns to distribute grease
in bearings.
• If unit has been stored more than one year, add grease before
start-up. (Refer to
“Lubrication Procedures” on page 9).
Installation Uncrating and Inspection
After uncrating, check for any damage which may have been incurred
in handling. The motor shaft should turn freely by hand. Repair or
replace any loose or broken parts before attempting to use the motor.
Check to be sure that motor has not been exposed to dirt, grit, or
excessive moisture in shipment or storage before installation.
Measure insulation resistance (see
dry the windings as required. Never start a motor which has been wet
without having it thoroughly dried.
Safety
Motors should be installed, protected and fused in accordance with
latest issue of National Electrical Code, NEMA Standard Publication
No. MG 2 and local codes.
Eyebolts or lifting lugs are intended for lifting the motor only. These
lifting provisions should never be used when lifting or handling the
motor with other equipment (i.e. pumps, gear boxes, fans or other
driven equipment) as a single unit. Be sure the eyebolt is fully
threaded and tight in its mounting hole.
Eyebolt lifting capacity ratings is based on a lifting alignment
coincident with the eyebolt centerline. Eyebolt capacity reduces as
deviation from this alignment increases. See NEMA MG 2.
Frames and accessories of motors should be grounded in accordance
with National Electrical Code (NEC) Article 430. For general
information of grounding refer to NEC Article 250. Rotating parts
such as pulleys, couplings, external fans, and shaft extensions should
be permanently guarded.
“Operation” on page 7). Clean and
4 AC Induction Motors
Location
In selecting a location for the motor, consideration should be given to
environment and ventilation. A motor with the proper enclosure for
the expected operating condition should be selected. The ambient
temperature of the air surrounding the motor should not exceed 40˚C
(104˚F) unless the motor has been specially designed for high
ambient temperature applications. The free flow of air around the
motor should not be obstructed.
The motor should never be placed in a room with a hazardous
process, or where flammable gases or combustible material may be
present, unless it is specifically designed for this type of service.
1. Dripproof (open) motors are intended for use indoors where
atmosphere is relatively clean, dry and non-corrosive.
2. Totally enclosed motors may be installed where dirt, moisture
and corrosion are present, or in outdoor locations.
3. Explosion proof motors are built for use in hazardous locations as
indicated by Underwriters’ label on motor. Consult UL, NEC,
and local codes for guidance. Refer to manufacturer for
application assistance.
Floor Mounting
Motors should be provided with a firm, rigid foundation, with the
plane of four mounting pads flat within 0.25 mm (0.010 in.) for 56 to
210 frame; 0.38 mm (0.015 in.) from 250 through 500 frame. This
may be accomplished by shims under the motor feet. For special
isolation mounting, contact manufacturer for assistance.
V-Belt Drive
1. Select proper type and number of belts and sheaves. Excessive
belt load will damage bearings. Sheaves should be in accordance
to NEMA Spec. MG-1 or as approved by the manufacturer for a
specific application.
2. Align sheaves carefully to avoid axial thrust on motor bearing.
The drive sheave on the motor should be positioned toward the
motor so it is as close as possible to the bearing.(104˚F) unless
the motor.
3. When adjusting belt tension, make sure the motor is secured by
all mounting bolts before tightening belts.
4. Adjust belt tension to belt manufacturers recommendations.
Excessive tension will decrease bearing life.
AC Induction Motors 5
Direct Connected Drive
Flexible or solid shaft couplings must be properly aligned for
satisfactory operation. On flexible couplings, the clearance between
the ends of the shafts should be in accordance with the coupling
manufacturer’s recommendations or NEMA standards for end play
and limited travel in coupling.
MISALIGNMENT and RUN-OUT between direct connected shafts
will cause increased bearing loads and vibration even when the
connection is made by means of a flexible coupling. Excessive
misalignment will decrease bearing life. Proper alignment, per the
specifications of the coupling being used, is critical.
Some large motors are furnished with roller bearings. Roller bearings
should not be used for direct drive.
Electrical Connections
ATTENTION: Install and ground per local and national
codes. Consult qualified personnel with questions or if
!
repairs are required.
ATTENTION: To guard against personal injury and/or
machine damage, assure that the following guidelines are
!
followed:
• Disconnect power before working on motor or driven
equipment.
• Motors with automatic thermal protectors will
automatically restart when the protector temperature
drops sufficiently. Do not use motors with automatic
thermal protectors in applications where automatic
restart will be hazardous to personnel or equipment.
• Motors with manual thermal protectors may start
unexpectedly after protector trips. If manual protector
trips, disconnect motor from power line. After
protector cools (five minutes or more) it can be reset
and power may be applied to motor.
• Discharge all capacitors before servicing motor.
• Keep hands and clothing away from moving parts.
• Never attempt to measure the temperature rise of a
motor by touch. Temperature rise must be measured
by thermometer, resistance, imbedded detector, or
thermocouple.
• Electrical repairs should be performed by trained and
qualified personnel only.
• Failure to follow instructions and safe electrical
procedures could result in serious injury or death.
• Ensure that safety guards are in use (if required).
6 AC Induction Motors
1. All wiring, fusing, and grounding must comply with National
Electrical Codes and local codes.
2. To determine proper wiring, rotation and voltage connections,
refer to the information and diagram on the nameplate, separate
connection plate or decal. If the plate or decal has been removed,
contact manufacturer for assistance.
3. Use the proper size of line current protection and motor controls
as required by the National Electrical Code and local codes.
Recommended use is 125% of full load amps as shown on the
nameplate for motors with 40˚C ambient and a service factor over
1.0. Recommended use is 115% of full load amps as shown on
the nameplate for all other motors. Do not use protection with
larger capacities than recommended. Three phase motors must
have all three phases protected.
Thermal Protector Information
Important: When motors are provided with thermal protection
(typically thermostats), it is important to properly connect
and apply the devices. This will ensure that the motor is
properly protected from being operated if thermal limits
are reached and/or exceeded. The control system must be
configured to reduce the motor load and/or shut down the
motor control system to allow the motor to cool to a level
within acceptable operating ranges. If the motor is
operated with the thermal protective devices tripped
(indicating an over temperature condition), the motor
insulation could be damaged and complete failure of the
motor insulation is possible. In the event of motor failure
due to an over temperature condition, Rockwell
Automation requires thatmotor thermal protective devices
(when supplied) be adequately monitored and
incorporated into the motor control system to maintain
warranty. Failure on the part of the individual installing
this equipment to take these steps will result in the factory
warranty being voided.
The nameplate will indicate one of the following:
• Motor is thermally protected,
• Motor is not thermally protected,
• Motor is provided with overheat protective device.
For examples, refer to the paragraphs below.
1. Motors equipped with built-in thermal protection have
“THERMALLY PROTECTED” stamped on the nameplate.
Thermal protectors open the motor circuit electrically when the
motor overheats or is overloaded. The protector cannot be reset
until the motor cools. If the protector is automatic, it will reset
itself. If the protector is manual, press the red button to reset.
2. Motors without thermal protection have nothing stamped on
nameplate about thermal protection.
AC Induction Motors 7
3. Motors that are provided with overheat protective device that
does not open the motor circuit directly will indicate “WITH
OVERHEAT PROTECTIVE DEVICE.”
a. Motors with this type of “Overheat Protective Device” have
protector leads brought out in the motor conduit box marked
“P1” and “P2.” These leads are intended for connection in
series with the stop button of the 3-wire pilot circuit for the
magnetic starter which controls the motor. See diagram.
b. The circuit controlled by the above “Overheat Protective
Device” must be limited to a maximum of 600 volts and 360
volt-amps.
Normally Closed Protectors Normally Open Protectors
P2P1
N.O motor thermostats may
be used in conjunction with
controls installed by an
OEM.
N.O.
P1 P2
N.C.
Protectors
to Control Voltage
Start
Stop
M
M
Hold
Coil
Protectors
Changing Rotation
1. Keep hands and clothing away from rotating parts.
2. Determine proper rotation BEFORE coupling motor to load.
3. Check rotation by jogging or bumping. Apply power to the motor
leads for a short period of time, enough to just get motor shaft to
rotate a slight amount to observe shaft rotating direction.
4. Three phase - interchange any two (2) of the three (3) line leads.
Single phase - reconnect per the connection diagram on the
motor. Normally Open (N.O.) motor thermostats may be used in
conjunction with controls installed by an OEM.
Reduced Voltage Starting
Motors used on reduced voltage starting, should be carefully selected
based upon power supply limitations and driven load requirements.
The motor starting torque will be reduced when using reduced
voltage starting. The elapsed time on the start step should be kept as
short as possible and should not exceed 5 seconds (recommended
time is 2 seconds). Refer to manufacturer for application assistance.
Operation Before Initial Starting
ATTENTION: To guard against personal injury and/or
equipment damage, remove all powerto the drive and motor
!
before performing installation, troubleshooting or
maintenance. Motors with automatic thermal protectors can
restart when the protector temperature drops sufficiently.
Do not use motors with automatic thermal protectors in
applications where automatic restart is undesirable.
8 AC Induction Motors
1. If a motor has become damp in shipment or in storage, measure
the insulation resistance of the stator winding.
Minimum Insulation Resistance (in Megohms) = 1 +
Do not attempt to run the motor if the insulation resistance is below this value.
Rated Voltage
1000
2. If insulation resistance is low, dry out the moisture in one of the
following ways:
a. Bake in oven at temperature not more than 90˚C (194˚F).
b. Enclose motor with canvas or similar covering. Leave a hole
at the top for moisture to escape, and insert heating units or
lamps.
c. Pass a current at low voltage (rotor locked) through the stator
winding. Increase the current gradually until the winding
temperature, measured with a thermometer, reaches 90˚C
(194˚F). Do not exceed this temperature.
3. Verify that voltage and frequency stamped on motor and control
nameplates correspond with that of the power line.
4. Check all connections to the motor and control with the wiring
diagram.
5. Be sure rotor turns freely when disconnected from the load. Any
foreign matter in the air gap should be removed.
6. Leave the motor disconnected from the load for the initial start
(see following Attention). Check for proper rotation.
Check for correct voltage (within +10% of nameplate value) and
that it is balanced within 1% at the motor terminals. After the
machine is coupled to the load, check that the nameplate amps are
not exceeded. Recheck the voltage level and balance under load
per the above guidelines.
Shut down the motor if the above parameters are not met or if any
other noise or vibration disturbances are present. Consult NEMA
guidelines or the equipment manufacturer if any questions exist
before operating equipment.
ATTENTION: To guard against personal injury and/or
machine damage, ensure that belts are properly installed,
!
before energizing any motor with a nameplate that reads
“Belted Duty Only.”
Allowable Voltage and Frequency Range
If voltage and frequency are within the following range, motors will
operate, but with different characteristics than obtained with correct
nameplate values.
1. Voltage: Within 10% above or below the value stamped on the
nameplate. On three phase systems the voltage should be
balanced within 1%. A small voltage unbalance will cause a
significant current unbalance.
AC Induction Motors 9
2. Frequency: Within 5% above or below the value stamped on the
nameplate.
3. Voltage and Frequency together: Within 10% (providing
frequency above is less than 5%) above or below values stamped
on the nameplate.
Cleanliness
Keep both the interior and exterior of the motor free from dirt, water,
oil and grease. Motors operating in dirty places should be periodically
disassembled and thoroughly cleaned.
Condensation Drain Plugs
All explosion proof and some totally enclosed motors are equipped
with automatic drain plugs, they should be free of oil, grease, paint,
grit and dirt so they don’t clog up. The drain system is designed for
normal floor (feet down) mounting. For other mounting positions,
modification of the drain system may be required, consult
manufacturer.
Service Important: If motor is nameplated for hazardous locations, do not run
motor without all of the grease or drain plugs installed.
Important: Overgreasing bearings can cause premature bearing and/
or motor failure. The amount of grease added should be
carefully controlled.
Important: If lubrication instructions are shown on the motor
nameplate, they will supersede this general instruction.
Motors are pregreased with a polyurea mineral oil NGLI
grade 2 type grease unless stated otherwise on the motor
nameplate. Some compatible brands of polyurea mineral
base type grease are: Chevron SRI #2,Rykon Premium #2,
Shell Oil Dolium R or Texaco Polystar RB.
Motors are properly lubricated at the time of manufacture. It is not
necessary to lubricate at the time of installation unless the motor has
been in storage for a period of 12 months or longer (refer to
lubrication procedure that follows).
Lubrication Procedures
1. Stop motor. Disconnect and lock out of service.
2. Remove contaminants from grease inlet area.
3. Remove filler and drain plugs.
4. Check filler and drain holes for blockage and clean as necessary.
5. Add proper type and amount of grease. See the Relubrication
Time Intervals table for service schedule and Relubrication
Amounts table for volume of grease required.
6. Wipe off excess grease and replace filler and drain plugs (see
Important statements above).
7. Motor is ready for operation.
10 AC Induction Motors
Relubrication Time Interval & Amounts - motors with regreasing provisions
NEMA Frame Size
140-180 210-360 400-510
Service
Condition
Standard 3 years 6 months 2 years 6 months 1 year 3 months
Severe 1 year 3 months 1 year 3 months 6 months 1 month
Seasonal See Note 2.
1
For motors nameplated as “belted duty only” divide the intervals by 3.
2
Lubricate at the beginning of the season. Then follow service schedule above.
1800 RPM
& Less
1
Over 1800
RPM
1800 RPM
& Less
Over 1800
RPM
1800 RPM
& less
Over 1800
RPM
SEASONAL SERVICE: The motor remains idle for a period of 6
months or more.
STANDARD SERVICE: Up to 16 hours of operation per day,
indoors, 38° C (100° F) maximum ambient.
SEVERE SERVICE: Greater than 16 hours of operation per day.
Continuous operation under high ambient temperatures 38˚-65˚ C
100˚-150˚ F) and/or any of the following: dirty, moist locations, high
vibration (above NEMA standards), heavy shock loading, or where
shaft extension end is hot.
Relubrication Amounts
(For motors with regreasing provisions).
Nema Frame Size Volume Cu. In. (Fluid Oz.)
140 0.25 (0.14)
180 0.50 (0.28)
210 0.75 (0.42)
250 1.00 (0.55)
280 1.25 (0.69)
320 1.50 (0.83)
360 1.75 (0.97)
400 2.25 (1.2)
440 2.75 (1.5)
500 3.00 (1.7)
Troubleshooting Refer to previous “Attention” statements before performing service or
troubleshooting.
If trouble is experienced in the operation of the motor, assure that:
• The bearings are in good condition and operating properly.
• There is no mechanical obstruction to prevent rotation in the
motor or in the driven load.
• The air gap is uniform. (Consult manufacturer for specifications).
• All bolts and nuts are tightened securely.
• Proper connection to drive machine or load has been made.
In checking for electrical trouble, assure that:
• The line voltage and frequency correspond to the voltage and
frequency stamped on the nameplate of the motor.
• The voltage is actually available at motor terminals.
AC Induction Motors 11
• The fuses and other protective devices are in proper condition.
• All connections and contacts are properly made in the circuits
between the control apparatus and motor.
Motor Troubleshooting Chart
These instructions do not cover all details or variations in equipment
nor provide for every possible condition to be met in connection with
installation, operation or maintenance. Should additional information
be desired for the purchaser’s purposes, the matter should be referred
to the manufacturer.
Your motor service and any troubleshooting must be handled by
qualified persons who have proper tools and equipment.
Trouble Cause What To Do
Motor fails to start Blown fuses Replace fuses with proper type and rating
Overload trips Check and reset overload in starter.
Improper power supply Verify that power supplied agrees with motor nameplate and load factor.
Improper line connections Check connections with diagram supplied with motor.
Open circuit in winding or control switch Indicated by humming sound when switch is closed. Check for loose
Mechanical failure Verify that motor turns freely. Check bearings and lubrication.
Short circuited stator Indicated by blown fuses. Motor must be rewound.
Poor stator coil connection Remove end bells, locate with test lamp.
Rotor defective Look for broken bars or end rings.
Motor may be overloaded Reduce load.
Motor stalls One phase may be open Check lines for open phase.
Wrong application Change type or size. Consult manufacturer.
Overload Reduce load.
Low voltage Verify that nameplate voltage is maintained. Check connection.
Open circuit Fuses blown, check overload relay, stator and pushbuttons.
Motor runs and then dies
down
Motor does not come up to
speed
Motor takes too long to
accelerate and/or draws
high amp
Wrong rotation Wrong sequence of phases Reverse connections at motor or at switchboard.
Motor overheats while
running under load
Power failure Check for loose connections to line, to fuses and to control.
Not applied properly Consult supplier for proper type.
Voltage too low at motor terminals because of
line drop.
Starting load too high Check load motor is supposed to carry at start.
Broken rotor bars or loose rotor Look for cracks near the rings. A new rotor may be required as repairs
Open primary circuit Locate fault with testing device and repair.
Excessive load Reduce load.
Low voltage during start Check for high resistance. Adequate wire size.
Defective squirrel cage rotor Replace with new rotor.
Applied voltage too low Get power company to increase power tap.
Overload Reduce load.
Frame or bracket vents may be clogged with
dirt and prevent proper ventilation of motor.
Motor may have one phase open Check to make sure that all leads are well connected.
Grounded coil Locate and repair.
Unbalanced terminal voltage Check for faulty leads, connections and transformers.
wiring connections. Also verify that all control contacts are closing.
Use higher voltage on transformer terminals or reduce load. Check
connections. Check conductors for proper size.
are usually temporary.
Open vent holes and check for a continuous stream of air from the
motor.
12 AC Induction Motors
Trouble Cause What To Do
Motor vibrates Motor misaligned Realign.
Weak support Strengthen base
Coupling out of balance Balance coupling.
Driven equipment unbalanced Rebalance driven equipment.
Defective bearings Replace bearing.
Bearings not in line Line up properly.
Balancing weights shifted Rebalance motor.
Polyphase motor running single phase Check for open circuit.
Excessive end play Adjust bearing or add shim.
Unbalanced line current on
polyphase motors during
normal operation
Scraping noise Fan rubbing air shield Remove interference.
Noisy operation Airgap not uniform Check and correct bracket fits or bearing.
Hot bearings general Bent or sprung shaft Straighten or replace shaft.
Hot bearings ball Insufficient grease Maintain proper quantity of grease in bearing.
Unequal terminal volts Check leads and connections.
Single phase operation Check for open contacts.
Unbalanced voltage Correct unbalanced power supply.
Fan striking insulation Clear fan.
Loose on bedplate Tighten holding bolts.
Rotor unbalance Rebalance.
Excessive belt pull Decrease belt tension.
Pulleys too far away Move pulley closer to motor bearing.
Pulley diameter too small. Use larger pulleys.
Misalignment Correct by realignment of drive.
Deterioration of grease or lubricant
contaminated
Excess lubricant Reduce quantity of grease, bearing should not be more than 1/2 filled.
Overloaded bearing Check alignment, side and end thrust.
Broken ball or rough races Replace bearing, first clean housing thoroughly.
Remove old grease, wash bearings thoroughly in kerosene and replace
with new grease.
AC Induction Motors 13
Typical Cutaway View of a Dripproof, Horizontal Integral Horsepower Motor
364 - 445 Frame Size
Item Description Item Description Item Description
1. Frame Vent Screen
1
11. Bracket O.P.E. 21. Bracket Holding Bolt
2. Conduit Box Bottom 12. Baffle Plate O.P.E. 22. Inner Bearing Cap P.E.
3. Conduit Box Top-Holding Screw 13. Rotor Core 23. Inner Bearing Cap Bolt
4. Conduit Box Top 14. Lifting Eye Bolt 24. Grease Plug
5. Conduit Box Bottom-Holding Bolt 15. Stator Core 25. Ball Bearing P.E.
6. Ball Bearing O.P.E.
2
16. Frame 26. Shaft Extension Key
2
7. Pre-loading Spring 17. Stator Winding 27. Shaft
8. Inner Bearing Cap O.P.E. 18. Baffle Plate Holding Screw 28. Drain Plug (grease)
9. Grease Plug 19. Baffle Plate P.E. 29. Bracket Screen
1
10. Inner Bearing Cap Bolt 20. Bracket P.E.
P.E. = Pulley End O.P.E. = Opposite Pulley End
1
Bracket and frame screens are optional.
2
Bearing Numbers are shown on motor nameplate when requesting information or parts always give complete motor description, model and serial numbers.
14 AC Induction Motors
Notes
Notes
AC Induction Motors 15
Online Documentation
The latest motor information can be obtained from the Allen-Bradley
Drives & Motors home page on the World Wide Web at:
http://www.controlmatched.com
Publication 1329M-UM001B-EN-P – August, 2001
Supersedes 1329M-UM001A-US-P dated April, 2000 Copyright © 2001 Rockwell Automation. All rights reserved. Printed in USA.
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