Method for winding coils of single-phase induction electromotor

A method for winding stator coils of a single phase induction electromotor comprising winding a starting coil, avoiding winding of the starting coil about selected slots, moving an outer coil pitch to form coil overlapping slots adjacent to the selected unused slots for eliminating unused teeth, whereby the starting coil overlaps the starting coil in the selected slots disposed in a starting winding with a 90.degree. electric angle for increasing the starting torque and promoting the operation efficiency of the electromotor.

FIELD OF THE INVENTION 
The present invention relates to a method for winding coils of single-phase 
induction electromotor and, in particular, to a method for winding coils 
of single-phase induction electromotor designed to promote operation 
efficiency and to improve starting torque by eliminating unused teeth 
between unused slots and coil overlapping slots in a starting winding, 
while keeping a 90.degree. electric angle is formed between the starting 
winding and main winding. 
DESCRIPTION OF THE PRIOR ART 
Generally, in many type of single-phase 4-polar induction electromotors, 
four unused teeth are existent between poles adjacent to main winding 
slots or between poles adjacent to starting winding slots and, in main 
winding, a magnetic flux produced from these unused teeth during operation 
does not rotate the rotor of electromotor but exercises a damping action 
on it due to counter electromotive force. 
Consequently, in the prior single-phase induction electromotor, in order to 
remove such unused teeth between poles adjacent to the main winding slots, 
an adjacent pole and its outer coil loop are wound in the same slot by 
one-slot expansion of coil pitch and by expansion of each coil loop of 
each pole. 
An example of such prior art main winding is illustrated in FIG. 1. In the 
single-phase 4-polar 36-slot induction electromotor, each coil pitch of 
coil C1 spans 1st slot to 10th slot, 2nd slot to 9th slot, 3rd slot to 8th 
slot and 4th slot to 7th slot and an outer coil path of coil C2 which 
forms an adjacent pole spans 10th slot to 19th slot. Consequently, 10th 
slot is jointly owned by the coil C1 and the outer coil pitch of coil C2. 
Thus, unused teeth are not existent. 
However, although it is the best way to wind a coil in the same manner as 
in the main winding in order to remove the unused teeth in the starting 
winding, an electric angle formed between the starting winding and the 
main winding cannot maintain a 90.degree. in the single-phase 4-polar 
induction electromotor. Therefore, there is no other way but to wind a 
coil in the starting winding so that the unused teeth may exist between 
respective adjacent poles. 
Thus such prior art induction electromotor is defective because the entire 
operation efficiency may drop by reducing its starting torque. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention is designed in consideration of such 
prior art defects as described hereinabove. It maintains a 90.degree. 
electric angle between the main winding and starting winding by moving 
only an outer coil pitch of coil formed each pole of starting winding to 
coil overlapping slots adjacent to unused slots of the starting winding, 
and eliminates the unused teeth from the starting winding for improving 
starting torque.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 2 is a summarized diagram showing that a main winding and a starting 
winding are wound through slots according to the present invention. It 
shows that all coil pitches of each pole are moved by one slot so that the 
main winding does not form unused teeth between respective poles formed by 
coils C1, C2, C3 and C4. 
At this time, the starting winding is provided with a 90.degree. electric 
angle disposed between the main winding and the starting winding without 
changing a size of an electric angle of the center of each pole formed by 
coils T5, T6, T7 and T8. However outer coil pitch slots, for example, 6th 
slot, 15th slot, 24th slot and 33rd slot, are owned jointly by the 
adjacent poles without the unavailable teeth between adjacent poles by 
moving an outer coil pitch of each coil T5-T8 outwardly to coil 
overlapping slots adjacent to unused slots of the starting wind. 
Accordingly, the electric angle of the pole center of an inner coil pitch 
of each pole of starting winding is coincident with that of the pole 
center of the outer coil pitch of the starting winding by offsetting by 
5.degree. in the 4-pole 36-slot induction electromotor of the present 
invention. 
The single-phase induction electromotor of the present invention removes 
the unavailable teeth by one-slot movement of only outer coil pitch of 
each pole and improves starting torque, thereby promoting the entire 
operation efficiency thereof.