Specifications

80
After winding several turns over the loop, insert the last end of the cord band through the
loop, and then pull the free end of the loop. This will pull the end under the Core band and secure
it there. Then the pulled end of the cord can be cut off. Use enough pressure in winding so that
the band will be tight.
Steel bands : Steel bands are laced on the front and back ends of the coils. These bands are
up on the armature in a different manner than in the cord bands. The procedure is illustrated in
Fig. 6.11, and is as follows. Place the armature in a lathe and lace mica or paper insulation in the
band slot around the entire armature to insulate the band from the coil sides. Hold the insulation
in lace by tying a turn of cord around it.
Place small strips of tin or copper under the cord, equidistant around the armature, in order
to secure the band after it is wound. Use the same gauge steel band wire as is found in the
original band. Steel bands must be up on the armature with much more pressure than is needed
for cord bands. It is therefore, necessary to utilize a device called a wire clam to provide the
required pressure.
Fig. 6.11
This device consists of two pieces of fibre fastened together by means of two screws and
two wing nuts. The steel band wire is fed through this clam to the armature. The clam has to be
secured to a bench so that it can be held stationary while slowly turning the armature while
banding.
Take care not to up too much pressure on the wire, otherwise it will break. After the band is
laced on the coil, copper or tin strips are turned over and the entire bend is soldered. One by one
each band is completed in this manner.
Testing the new winding : After the rewinding and connections are completed, it is important
that both the winding and the connections are tested for shorts, grounds, open circuits and
correctness of connections. This must be done before varnishing the winding so that any defect
that is found may be corrected more readily.