Lincoln Electric RANGER 250 SVM150-A Service Manual page 74

F-24
TEST PROCEDURE
1. Turn the engine off.
2. Perform the Case Cover Removal proce-
dure.
3. Locate and label the four leads from the rotor
brush holder assembly.
Using the needle nose pliers, remove the
leads. See Figure F.7. This will electrically
isolate the rotor windings.
4. Using the ohmmeter, check the rotor winding
resistance across the slip rings. See Figure
F.7. Normal resistance is approximately 4.7
ohms.
TROUBLESHOOTING & REPAIR
ROTOR RESISTANCE TEST (continued)
FIGURE F.7 – ROTOR BRUSH LEADS
SLIP RINGS
BRUSHES
LEADS
200A
200
LEADS
201
5H
+
See Figure F.7.
RANGER 250
-
5. Measure the resistance to ground.
one meter probe on either of the slip rings.
Place the other probe on any good unpaint-
ed ground. The resistance should be very
high, at least 500,000 ohms.
6. If the test does not meet the resistance spec-
ifications, then the rotor may be faulty.
Replace.
7. Connect the leads previously removed from
the brush assembly. Make sure the leads
are connected to the proper brushes. See
the Wiring Diagram.
8. If finished testing, perform the Case Cover
Replacement procedure.
F-24
Place