PASCO SE-8657 MOTOR ACCESSORY - Manual (Page 24)

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Motor Accessory 012-06247A
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➂ Working from above, press the brush holder onto the smooth, enlarged portion of the
shaft. Apply increasingly firm pressure equally to each side of the brush holder while
rotating the brush holder back and forth. If this action loosens the retaining nut, tighten
it more tightly, as described in step 2.
Check to be sure the brush assembly is seated as far down on the shaft as it will
go.
➃ Gently lower the armature onto the shaft with the dual slip- ring commutator down.
Carefully rotate the armature back and forth to separate the brushes and allow the
commutator to slip down between them. If necessary, insert a pencil or similar object
down between the brushes. Use only the most delicate force to avoid bending the
brushes and necessitating adjustments or repairs.
➄ Adjust the gap of the Variable Gap Magnet so there is approximately 1 mm of clearance
between the flat pole pieces and the armature when it is rotated by hand.
Procedure—Part A
➀ Remove the armature from the shaft by grasping it between your thumb and forefinger
and rotating it back and forth while lifting gently. If necessary, insert a pencil between
the brushes to gently separate them so they don’t prevent removal of the armature.
➁
Examine the armature closely and imagine current entering one of the two slip rings
from a brush. Trace the path of the current through the wire to the coil, through the coil,
through the wire to the coil on the opposite side of the armature, through that coil, and
through the wire to the other slip ring and into the second brush. By carefully examin-
ing the part of the coils where the leads emerge from the coil, you should be able to
determine the direction in which the wire is wound on the coil.
Figure 1. Installation of the Motor
Accessory onto the Variable Gap
Magnet
armature
wrench/
retaining nut
brushes
brush holder
dual slip-ring
commutator
leave 1mm
exposed at
installation
shaft
magnet
base
flat pole pieces