Specifications

Fig. 6.10

Brazing: In the case of large armature windings, the armature winding lead ends are brazed

with the respective commutator raiser slits by means of a gas torch. Close inspection and care

should be exercised in the control of the flame.

Hot stacking : In the case of small DC armature conductors are kept in the commutator raiser

slits and spot welded. This is called hot stacking. A specially designed hot-stacking machine is

available for this purpose.

Banding the armature : A temporary banding is sometimes applied on the armature before the

permanent banding is done, to keep the coils in position and to facilitate shaping of the overhang.

Permanent bands are used on armatures to hold the armature end leads in position. A cord

band is used on small armatures to prevent the leads from flying out of the slots, while the

armature is rotating.

Large armatures have steel bands for the same purpose. For large armatures having

open-type slots, steel or tae bands are used to prevent the coil from flying out of the slots.

Cord bands : The procedure for making a cord band on an armature is shown in Fig. 6.10, and

the following directions should be observed. Use a proper size of banding cord heavy for larger

armatures, light for smaller armatures. Start at the end nearest the commutator and wind several

turns in layers, allowing about 150mm long cord at the beginning to be free. Bend the cord in the

form of a loop.