Figure 24-l6. Testing Rotor for Ground Figure 24-17. Testing Rotor for Opens or Shorts
2. To check for an open field coil, connect an ohmmeter to slip rings.
a. Ohmmeter should read between 1.5 and 2.0 ohms on rotor coils at room ambient conditions.
b. Ohmmeter should read between 2.5 and 3.0 ohms on rotor coils that have been operated on aircraft
at higher engine compartment temperatures.
c. Readings above 3.5 ohms indicate high resistance rotor coils and further test or replacement may
be required.
3. To check for a shorted field coil, connect an ohmmeter to two slip rings. If reading is below
l.5 ohms, field coil is shorted.
SLIP RINGS
Slip rings are considered to be part of rotor assembly and are not serviced as a separate item.
ASSEMBLY OF ALT ERNATOR
l. Position grease retainer on rotor shaft and press retainer on shaft with installer tool C-3921. Plastic
retainer is properly positioned when inner bore of installer tool bottoms on rotor shaft. (Refer to figure
24-l8.)
24 - 32 - 00
Page - 24 - 21
Reissued: August 1, 1986
1I20
PIPER AIRCRAFT
PA-28-236
MAINTENANCE MANUAL
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