Hudson 1948 - 1952, Service Manual

Page: 150 / 333

6 - 14 ELECTRICAL SYSTEM
FIELD COIL REPLACEMENT:
1. Solder terminal post to new coil. (Use rosin core solder.)
2. Assemble coil on pole shoe and Install in frame. (Make
sure pole shoe is in position marked before removing
from frame.)
3. Coat pole shoe screw with boiled linseed oil and Install
in frame.
4. As screw is tightened, strike the frame several sharp
blows with a soft hammer to align shoe.
5. Twist and solder connection between the two field coils
and assemble terminal stud in frame.
6. Test field coil draw (short circuit test},
ARMATURE GROUND TEST:
1. Place armature on V-block or growler and touch one test
probe to armature core.
2. Touch other test probe to each commutator segment in
turn. (Touch probes to ends or shoulders of segment - not
to brush or hearing surfaces.)
3. If lamp lights, armature is grounded and should be re-
placed.
ARMATURE OPEN CIRCUIT TEST:
1. With armature on V-block or growler, touch test probes
to each pair of adjacent commutator segments. (Do not
touch brush surfaces.)
2. If lamp does not light at any pair of segments, an open
circuit exists, and armature should be replaced.
ARMATURE SHORT CIRCUIT TEST:
1. Place armature on a growler and hold a thin strip of steel
or hack saw blade on the armature core.
2. Rotate armature slowly.
3. Steel strip will vibrate if armature is shorted.
4. If short is present, replace armature.
ARMATURE COMMUTATOR REPAIR:
1. Place armature on V-blocks and check commutator
runout with dial indicator.
2. If total runout exceeds .003", commutator should be
turned down.
3. If commutator diameter after turning is less than 1.60
inches, replace armature.
4. Remove burrs from commutator with 00 sandpaper.
5. Undercut mica between armature segments to a depth of
1/32''. (Mica may be undercut with a hack saw blade if set
of teeth is ground to the exact width of the cut.)
BRUSH HOLDERS:
1. Touch one test. probe to insulated brush holder and
ground the other probe to the end head. If lamp lights,
brush holder is grounded.
2. Place armature in soft jawed vise and Install commutator
end head and brushes. Brushes should slide freely in the
holders and be in perfect alignment with commutator
segments.
3. Hook a spring scale in the hole in the end of the brush
arm. Pull the scale on a line parallel to the face of the
brush. Scale should indicate 35 to 53 ounces (with new
brushes) just as the arm leaves the brush.
NOTE: The brush spring tension must be correct. Exces-
sive tension will wear brushes and commutat or rapidly;
Low-tension will cause arcing and burning of brushes
.
4. Adjust spring tension by bending springs.