Power Train
Testing And Adjusting
Pitch BarÐMarks on the Commutator Surface
Pitch barÐmarks cause low or burnt marks on the
commutator surface.
Field Coil and Terminal Tests
Open Circuit Test
Open Circuit Test
1.
Put the digital multimeter Function/Range Switch
on the 200 ohm resistance (½) scale.
2.
Put one test probe to each outer field terminal
(S1,S2).
3.
The resistance must be less than one ohm. If the
resistance is too high, it is an indication of
corrosion on the terminals or an open field coil.
Ground Test
Ground Test
(1) Field Terminal. (2) Motor housing.
1.
Put the digital multimeter Function/Range Switch
on the 20M resistance (½) scale.
2.
Put one test lead to either outer field terminal (1)
and the other test lead to the motor housing (2).
There must be more than one megohm resistance.
3.
If there is a measurement of less than one
megohm, it can be caused by wet insulation on the
field windings or excessive brush dust in housing.
Heat the motor at 88
°
C (190
°
F) until the resistance
goes above one megohm. If the resistance does
not go above one megohm, the shell and field
assembly must be replaced.
Tools Needed
Digital Multimeter Or Equivalent
1
18
EHPS013B
1
2
