Chapter 3 Ch3

User Manual: Chapter 3 IronHorse DC Motors Manual - AutomationDirect

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Page 3–1IronHorse General Purpose DC Motors User Manual – 2nd Ed. Rev. A – 11/20/2017

Maintenance and

Troubleshooting 3

3

3

Chapter

Chapter

Chapter

Table of Contents

Routine Maintenance � � � � � � � � � � � � � � � � � � � � � � � � � � 3–2

BeaRing Size infoRMation � � � � � � � � � � � � � � � � � � � � � � � � 3–2

Replacing BRuSheS � � � � � � � � � � � � � � � � � � � � � � � � � � � 3–3

tRouBleShooting � � � � � � � � � � � � � � � � � � � � � � � � � � � � 3–4

Page 3–2 IronHorse General Purpose DC Motors User Manual – 2nd Ed. Rev. A – 11/20/2017

Chapter 3: Maintenance and Troubleshooting

Routine Maintenance

A routine maintenance schedule should be developed for every IronHorse motor installation

based on the individual application. Motors installed in a harsh running environment should be

serviced more frequently than those installed in a clean, climate controlled area. The following

list should be used as a basis for creating the routine maintenance schedule.

1) Clean the motor housing using a brush, soft cloth or compressed air. Remove any dirt and

dust from the fan and fan cover vents.

2) Frequently monitor the bearing temperature on the motor. It should not exceed 60°C

(140°F).

3) Have the insulation checked periodically by an authorized motor specialist.

4) Replace the motor brushes after every 2500 hours of operation.

Bearing Size Information

Bearing Chart

Frame Size Drive End Bearing SKF

Type

Opposite Drive End

Bearing SKF Type

Small-Frame not user serviceable

56C 6203 6203

All IronHorse 56C-frame motors use premium sealed SKF brand bearings.

Chapter 3: Maintenance and Troubleshooting

Page 3–3IronHorse General Purpose DC Motors User Manual – 2nd Edition – 11/20/2017

Replacing Brushes

Warning: To prevent serious personal injury and damage to your

equipment, always disconnect input power before replacing brushes.

A spare set of brushes ship in each 56C-frame PMDC motor box, and the brushes should be

replaced after every 2500 hours of operation. Small-frame PMDC motor brushes should be

replaced as needed. If you visually inspect the brushes, the minimum acceptable length is 6mm.

See “Chapter 4: Accessories” for replacement brush ordering information. Make sure you install

the correct replacement brushes; check the part numbers carefully. Ensure that the replacement

brushes are the same width as the brushes being removed from the motor. DO NOT install

smaller brushes in a larger motor. There is no break-in period with new brushes.

Replacement brush and spring assembly sets:

NOTE: The brushes are spring-loaded. Be careful when removing the

brush cover.

Motor has two brushes; one on each side

of the motor.

Always replace the brushes in pairs.

1) Remove the brush cover using a

athead screwdriver as shown. Turn

the brush cover counterclockwise to

remove.

2) Carefully remove the old brush and

spring assembly and install the

replacement.

3) Reinstall the brush cover, turning

clockwise.

4) Replace the other motor brush and

spring following the same steps.

Page 3–4 IronHorse General Purpose DC Motors User Manual – 2nd Ed. Rev. A – 11/20/2017

Chapter 3: Maintenance and Troubleshooting

Troubleshooting

To prevent serious damage, faults observed when a motor first goes into service or during

subsequent operation should be investigated and repaired immediately. These troubleshooting

tables cover most common PMDC motor problems.

Warning: To prevent serious personal injury and damage to your

equipment, always disconnect input power before inspecting or repairing

your motor.

Mechanical Problems – Noise While Running

Problem Possible Causes Solutions

Motor vibrates or

runs noisily when

coupled up, but

runs okay when

uncoupled.

Defective transmission components, or

problem with the machine being driven.

Inspect transmission and drive

components. Check alignment.

Foundation has become unlevel. Realign machine set. Check and

repair foundation level.

Problem with gear drive. Align drive, check driving and driven

gear pitch circles.

Incorrectly balanced drive or driven

machine components.

Re-balance drive and/or driven

components.

Motor runs rough

when uncoupled.

Bearing damage. See Bearing Problems

troubleshooting table.

Mounting bolts are loose. Re-tighten and lock mounting bolts.

Fitted drive components (coupling or

pulleys) affecting rotor balance.

Balance rotor with coupling or pulley

fitted.

Mechanical Problems – Roller Bearing Problems

Problem Possible Causes Solutions

Scratching, rubbing,

or rumbling noise

from bearing.

Bearing is defective. Replace bearing. *

Whistling noise

from bearing.

Bearing has run dry. Replace bearing. *

Faulty cage. Replace bearing. *

Excessive bearing

wear. Bearing overloaded.

Check alignment, belt tension, gear pressure,

coupling thrust. Reduce bearing load. If

needed, reduce additional axial load.

Scoring when motor

is inoperative.

Bearing is being subjected to vibration

from outside source.

Isolate motor from source of vibration or

keep motor turning over.

Scoring when motor

running. Current leakage. Remove motor from service. Repair or

replace motor.

* Bearings in the small-frame PMDC motors are not user replaceable; replace motor instead of bearings.

Chapter 3: Maintenance and Troubleshooting

Page 3–5IronHorse General Purpose DC Motors User Manual – 2nd Edition – 11/20/2017

Troubleshooting (continued)

Electrical Problems

Problem Possible Causes Solutions

Motor shaft rotates in wrong

direction (should rotate

clockwise when facing

shaft).

Positive (+) and negative

(-) input power leads are

reversed.

Switch the input power connections.

Motor fails to start off-load.

Break in the armature supply. Check and repair connection.

Fuse is blown. Replace fuse.

Controller damaged or

incorrectly connected. Check starter for break in circuit and repair break.

Armature coils burned out or

short-circuiting.

Correct short circuit. This may require bringing the

motor to a repair shop.

Brushes not bearing down

correctly.

Check brush position and bearing pressure.

Replace worn brushes.

Jerky starting.

Break in starter circuit. Repair break.

Armature short-circuit. Correct short circuit. This may require bringing the

motor to a repair shop.

Commutator short-circuit. Check commutator and repair short-circuit.

Motor will not run under

load.

Short circuit in the supply. Locate short circuit and repair.

Overloading. Check current input and remedy overload.

Voltage drop. Increase supply line cross section.

Motor overspeeding and

hunting while under load. Controller.

Decrease IR compensation.

Check speed potentiometer wiring and signal, and

repair if needed.

Motor overheating.

Overloading. Check voltage and current levels, and correct

overload condition.

Insufficient airflow. Improve cooling conditions.

Cooling air temperature too

high. If TEFC model, inspect the fan for damage.

Armature winding short-circuit. Check windings and soldered connections. Repair

coils or windings.

Page 3–6 IronHorse General Purpose DC Motors User Manual – 2nd Ed. Rev. A – 11/20/2017

Chapter 3: Maintenance and Troubleshooting

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