two speed motor
two speed motor
(OP)
how does a two speed motor work? does the motor start on half the windings and runs on all the windings or is the motor really split into two motors. the first motor start it and then both run it?
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RE: two speed motor
There is another technique called subsequent pole where the windings will be connected so as to form 4 poles, N, S, N, S.
The motor will approach a synchronous speed of 1800 RPM. (1750 more or less)
Half of the windings are then reversed to form N, N, N, N.
South poles are subsequently developed between the north poles and the motor approaches a synchronous speed of 900 RPM.
Depending on the winding pitch, not all motors are suitable for consequent pole operation.
The conventions "North" and "South" apply to instanteneous conditions. One half cycle later all the north poles will be south poles and vice versa.
respectfully
RE: two speed motor
RE: two speed motor
h
regards,
bill
"Whenever you are asked if you can do a job, tell them, certainly I can! Then get busy and find out how to do it." Theodore Roosevelt.
RE: two speed motor
Adding to the others comments note the Synch RPM = 120 F/P,
Where F is the line frecuency and P the pairs of poles, then the speed is dependant on the numbers of pair of poles and line frecuency.
You can find three kinds of two speed motors:
1. Dahlander conected, very well explained above.With only one winding making external conection you can obtain one speed or the double due to a P change, in this motors High Speed/Low Speed = 2.
2. PAM(pole amplitude modulation) With only one winding too the speed change is possible because the stator is windded with one special internal connection ,when the stator is energized, in one external connection, two differents magnetic field are produced, the superimposition of the two-fields result in an specific speed, in this motors the High speeed/Low speed is different than 2. (4/6 poles) or (2/8 poles).
3.Two separate windings or Dual wound: In this case, the simplest, the motor has two different windings windded in the same stator.
I hope this can help you
Best regards
Petronila
RE: two speed motor
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: two speed motor
Three phase motors : you could have two or three windings windded in the same stator.
For two windings: one is dahlander and the other is normal = 3 speeds or two dahlanders= 4 speeds.
For three windings: two are dahlander and one normal= 5 speeds, Three dahlander= 6 speeds. One dahlander and two normal= 4 speeds.
The dahlander winding could be replaced with PAM winding.
For Single phase you can find one start winding with two run windings (4/6 poles) others single phase used in air conditioned matters change the speed adding turns by taps on the Run winding this cause a very slight speed change.
Regards
Petronila
RE: two speed motor
Thank you Petronila.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com