Taylor-Dunn ET-015-00 Operation, T Roubleshooting And Replacement Parts Manual Download

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Motor Service

Motor

Page 3

Inspection

1. Measure the length of each motor brush.

• If any one brush is less than or equal to the

service limit specified in section

Service

Limits

, then all four brushes should be

replaced. Refer to

Replacing the Brushes

section for information regarding replacing the
motor brushes.

2. Measure the diameter of the commutator.

• If the commutator is less than the minimum

diameter specified in section

Service Limits

then the motor must be replaced.

3. Measure the commutator undercut depth in 5-

places around the commutator.

• If any one of the measurements is less than the

minimum undercut depth specified in

Service

Limits

above, then the commutator must be

undercut. Refer to

Repair Commutator

section for information regarding undercutting
the commutator.

4. Inspect the commutator for grooves.

• If the commutator is groved then it must be

machined on a lathe. Do not machine the
commutator past the minimum diameter
specified in

Service Limits

section. Refer to

Repair Commutator

section for information

regarding machining the commutator.

Insulation

Commutator

Incorrect

Hacksaw blade

Correct

Min. OD

Armature

Undercut

5. Inspect the commutator for burn marks.

• Burn marks and/or raised commutator segments

90 or 180 degrees apart is evidence of a shorted
armature. A tool called a growler is required to
reliably test for a shorted armature.

6. Inspect the commutator for raised segments.

Raised segments could be a result of a stalled
motor or shorted armature. A tool called a growler
is required to reliably test for a shorted armature.

• If the armature is not shorted then the raised

segments can be removed by machining the
commutator. Do not machine the commutator
past the minimum diameter specified in

Service Limits

section. Refer to

Repair

Commutator

section for information regarding

machining the commutator.

7. Visually inspect the armature windings for burnt

insulation. Burnt insulation is a direct result of
motor overheating and could lead to a shorted
armature.

• If the insulation is cracked or burnt, then it is

recommend that the armature or motor be
replaced.

NOTE: If the armature has been burnt then there is a

good possibility that the field windings may
also be burnt. Symptoms indicating a shorted
field include high motor current, lack of power
and possibly excessive speed.

8. Using a growler, test the armature for shorts.

• If the armature is shorted, then we recommend

that the armature or motor be replaced.

9. Using the continuity function of digital multi meter,

check the continuity around the entire commutator
by placing one test lead against one of the
commutator segments and the other test lead
against all of the other segments one at a time.
There should be continuity around the entire
commutator. If any segment indicates an open
circuit, then the motor must be replaced.

Typical burn mark on a shorted armature