The wave winding is possible only with particular number of conductors and poles and slots combinations. Some times the standard stampings do not consist of the number of slots according to the design requirements and hence the slots and conductor combination will not produce a mechanically balanced winding. Under such conditions some coils are placed in the slots, not connected to the remaining part of the winding but only for mechanical balance. Such windings are called dummy coils.
Why can't the need be fulfilled with the main winding itself ? -because for electromagnetism we have to required field winding when we are not using permanent magnetism. Since the residual magnetism is not sufficient for high power generator we have required the Field winding along with Main winding.
for the wave winding Y(avg) =(Z+-2)/P, the result of the avg Y must be an integer , therefore wave winding is possible only with a particular no. of coils sides or conductors. in such cases dummy coils are used but they are not electrically connected to the commutator. they r only used to preserve the balance of the machine.this problem doesnt exist in lap windings. there is no problem of fractions there.
for e.g if slots=16, each slot has 2 coil sides in it. poles =4 Yav=(Z+-2)/4=8.5 or 7.5 but the avg pitch must be an integer. so the winding isnot possible with 32 conductors. now if we use only 30 conductors instead of 32 ,,,,we get integers. (8 or 7). hence in both cases 2 coil sides r inactive n r called dummy coils.
The wave winding is possible only with particular number of conductors and poles and slots combinations. Some times the standard stampings do not consist of the number of slots according to the design requirements and hence the slots and conductor combination will not produce a mechanically balanced winding. Electromagnetism we have to required field winding when we are not using permanent magnetism. Since the residual magnetism is not sufficient for high power generator we have required the Field winding along with Main winding.
since wave winding can be done only with only some specific number of conductors and poles and slots,for examp-for wave winding Y(avg) =(Z+-2)/P, the result of the avg Y must be an integer if it is not then we can change the value of Z using dummy coils,in lap winding Z involved is always even so no fractional error takes place,so no need of dummy coils
In wave winding all the slots available on the armature are not completely filled by the coils. Due to this there weight is not uniformly balanced over the armature. This lead to non-uniform torque applied on the armature. This change in torque change the rotation (N) of the armature. Due to change in N, generated e.m.f. (Eg) also changes. That means, voltage that will applied to load will also change, which should remains constant.
The wave winding is possible only with particular number of conductors and poles and slots combinations. Some times the standard stampings do not consist of the number of slots according to the design requirements and hence the slots and conductor combination will not produce a mechanically balanced winding. Electromagnetism we have to required field winding when we are not using permanent magnetism. Since the residual magnetism is not sufficient for high power generator we have required the Field winding along with Main winding.
Q.2. Why can't the need be fulfilled with the main winding itself ? Ans:-For electromagnetism we have to required field winding when we are not using permanent magnetism. Since the residual magnetism is not sufficient for high power generator we have required the Field winding along with Main winding
The wave winding is possible only with particular number of conductors and poles and slots
ReplyDeletecombinations. Some times the standard stampings do not consist of the number of slots according to the
design requirements and hence the slots and conductor combination will not produce a mechanically
balanced winding. Under such conditions some coils are placed in the slots, not connected to the remaining
part of the winding but only for mechanical balance. Such windings are called dummy coils.
Why can't the need be fulfilled with the main winding itself ?
ReplyDelete-because for electromagnetism we have to required field winding when we are not using permanent magnetism. Since the residual magnetism is not sufficient for high power generator we have required the Field winding along with Main winding.
my answer is same.
Delete-----ankita
for the wave winding Y(avg) =(Z+-2)/P, the result of the avg Y must be an integer , therefore wave winding is possible only with a particular no. of coils sides or conductors. in such cases dummy coils are used but they are not electrically connected to the commutator. they r only used to preserve the balance of the machine.this problem doesnt exist in lap windings. there is no problem of fractions there.
ReplyDeletefor e.g if slots=16, each slot has 2 coil sides in it.
poles =4
Yav=(Z+-2)/4=8.5 or 7.5
but the avg pitch must be an integer. so the winding isnot possible with 32 conductors. now if we use only 30 conductors instead of 32 ,,,,we get integers. (8 or 7). hence in both cases 2 coil sides r inactive n r called dummy coils.
The wave winding is possible only with particular number of conductors and poles and slots
ReplyDeletecombinations. Some times the standard stampings do not consist of the number of slots according to the
design requirements and hence the slots and conductor combination will not produce a mechanically
balanced winding.
Electromagnetism we have to required field winding when we are not using permanent magnetism. Since the residual magnetism is not sufficient for high power generator we have required the Field winding along with Main winding.
since wave winding can be done only with only some specific number of conductors and poles and slots,for examp-for wave winding Y(avg) =(Z+-2)/P, the result of the avg Y must be an integer if it is not then we can change the value of Z using dummy coils,in lap winding Z involved is always even so no fractional error takes place,so no need of dummy coils
ReplyDeleteIn wave winding all the slots available on the armature are not completely filled by the coils.
ReplyDeleteDue to this there weight is not uniformly balanced over the armature.
This lead to non-uniform torque applied on the armature.
This change in torque change the rotation (N) of the armature.
Due to change in N, generated e.m.f. (Eg) also changes.
That means, voltage that will applied to load will also change, which should remains constant.
It can accomplished by using Lap winding
ReplyDeleteThe wave winding is possible only with particular number of conductors and poles and slots
ReplyDeletecombinations. Some times the standard stampings do not consist of the number of slots according to the
design requirements and hence the slots and conductor combination will not produce a mechanically
balanced winding.
Electromagnetism we have to required field winding when we are not using permanent magnetism. Since the residual magnetism is not sufficient for high power generator we have required the Field winding along with Main winding.
Q.2. Why can't the need be fulfilled with the main winding itself ?
ReplyDeleteAns:-For electromagnetism we have to required field winding when we are not using permanent magnetism. Since the residual magnetism is not sufficient for high power generator we have required the Field winding along with Main winding