- #1
b.shahvir
- 284
- 25
Hi,
Of late, I’m dabbling with flux variation patterns in an induction motor at ‘no-load’, ‘full-load’ and ‘standstill (locked rotor)’ conditions. The concept I’m following is that an induction motor can be considered as a generalized transformer. The equivalent circuit depicts that the mutual flux which links both the stator and rotor conductors falls appreciably as the load on the motor increases and the fall in mutual flux is very much pronounced at standstill condition (short-circuited transformer secondary).
Also, at standstill and at full load or near full load conditions, there are appreciable ‘reflected’ rotor currents in the stator windings of the motor analogous to the case of a loaded transformer, wherein the load currents are reflected in appropriate ratio on the primary side. But in case of a transformer, all this happens ‘statically’ due to the demagnetizing/neutralizing effects of the secondary winding flux which ‘dampens’ the mutual flux.
But an induction motor is a rotating machine!...hence I want to understand the manner in which the rotor induces reflected currents in the stator winding of the motor. Is it due to the dynamically induced EMFs as is the case in a generator (since rotor as well as rotor flux also keeps rotating around the air-gap as the mutual flux revolves synchronously around the stator)….. or by statically induced EMFs as is the case in a transformer? Is there any online link or article available which depicts the mechanism of flux variations or reflected stator currents for the above mentioned conditions in an induction motor?
Any kind of help will be greatly appreciated.
Thanks & Regards,
Shahvir
Of late, I’m dabbling with flux variation patterns in an induction motor at ‘no-load’, ‘full-load’ and ‘standstill (locked rotor)’ conditions. The concept I’m following is that an induction motor can be considered as a generalized transformer. The equivalent circuit depicts that the mutual flux which links both the stator and rotor conductors falls appreciably as the load on the motor increases and the fall in mutual flux is very much pronounced at standstill condition (short-circuited transformer secondary).
Also, at standstill and at full load or near full load conditions, there are appreciable ‘reflected’ rotor currents in the stator windings of the motor analogous to the case of a loaded transformer, wherein the load currents are reflected in appropriate ratio on the primary side. But in case of a transformer, all this happens ‘statically’ due to the demagnetizing/neutralizing effects of the secondary winding flux which ‘dampens’ the mutual flux.
But an induction motor is a rotating machine!...hence I want to understand the manner in which the rotor induces reflected currents in the stator winding of the motor. Is it due to the dynamically induced EMFs as is the case in a generator (since rotor as well as rotor flux also keeps rotating around the air-gap as the mutual flux revolves synchronously around the stator)….. or by statically induced EMFs as is the case in a transformer? Is there any online link or article available which depicts the mechanism of flux variations or reflected stator currents for the above mentioned conditions in an induction motor?
Any kind of help will be greatly appreciated.
Thanks & Regards,
Shahvir
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