Hello,
We have 08 motor of rating 15KW, 6 Pole, 415V, 975 RPM, CGL make installed. these induction motor has anti Condensate winding heating provision given of 24V AC (Between R and Y phase by contactor logic) through its power cable lead. when motor is in stop condition. there is a timer of 3 sec installed in control circuit between motor stop and winding heating to start.
One motor was overhauled and when it restored without coupled to the load, it runs perfectly fine but when we stop it, within 3 Sec (as per logic) 24V AC between R and Y phase (4.5 Amp current in R & Y phase) gets start and motor remain in continuous in running state with reduced speed, even though its mains supply (440V AC through power contactor) gets isolated.
Since the motor is decoupled and its self-inertia is high and it does not come to zero speed within 3 Sec of stoppage and 24V AC (Winding heating) between R & Y phase gets start and it remain continue in rotation with reduced speed (may be due to required rotating field gets fulfilled with 24V AC in 2 phase, Like single phasing happen in 3-phase motor at low load condition)
When we remove 24V AC winding heating space heater fuse, motor come down to its zero speed.
This seems a unique finding, please share any experience related to this and some theory part.
How can only 24V AC between two phase (R &Y) can drive a torque to a running 3-phase AC Induction motor even though mains supply get isolated..?? however it runs in solo run condition and with reduced speed.
We have 08 motor of rating 15KW, 6 Pole, 415V, 975 RPM, CGL make installed. these induction motor has anti Condensate winding heating provision given of 24V AC (Between R and Y phase by contactor logic) through its power cable lead. when motor is in stop condition. there is a timer of 3 sec installed in control circuit between motor stop and winding heating to start.
One motor was overhauled and when it restored without coupled to the load, it runs perfectly fine but when we stop it, within 3 Sec (as per logic) 24V AC between R and Y phase (4.5 Amp current in R & Y phase) gets start and motor remain in continuous in running state with reduced speed, even though its mains supply (440V AC through power contactor) gets isolated.
Since the motor is decoupled and its self-inertia is high and it does not come to zero speed within 3 Sec of stoppage and 24V AC (Winding heating) between R & Y phase gets start and it remain continue in rotation with reduced speed (may be due to required rotating field gets fulfilled with 24V AC in 2 phase, Like single phasing happen in 3-phase motor at low load condition)
When we remove 24V AC winding heating space heater fuse, motor come down to its zero speed.
This seems a unique finding, please share any experience related to this and some theory part.
How can only 24V AC between two phase (R &Y) can drive a torque to a running 3-phase AC Induction motor even though mains supply get isolated..?? however it runs in solo run condition and with reduced speed.
