Decelerate 2 Speed Motor by Connecting to Low Speed Winding
Decelerate 2 Speed Motor by Connecting to Low Speed Winding
(OP)
Hello All,
An interesting idea was raised today by my colleague. Let's say you have 3 phase, 2 speed (3600/1800 RPM) consequent winding motor and you're running it at no load at 3600 RPM. Shut the power off, reconnect for the lower speed and energize. At point of energizing the low speed, let's say the motor was still spinning at 3000 RPM but 1 minute has already passed. What happens to the motor. Does it rapidly slow down to the low speed (1800 RPM)? Is there any power generated back into the power lines as the motor is slowing down because the motor was spinning faster than synchronous speed at the point when it was energized?
Thank you,
eemotor
An interesting idea was raised today by my colleague. Let's say you have 3 phase, 2 speed (3600/1800 RPM) consequent winding motor and you're running it at no load at 3600 RPM. Shut the power off, reconnect for the lower speed and energize. At point of energizing the low speed, let's say the motor was still spinning at 3000 RPM but 1 minute has already passed. What happens to the motor. Does it rapidly slow down to the low speed (1800 RPM)? Is there any power generated back into the power lines as the motor is slowing down because the motor was spinning faster than synchronous speed at the point when it was energized?
Thank you,
eemotor





RE: Decelerate 2 Speed Motor by Connecting to Low Speed Winding
RE: Decelerate 2 Speed Motor by Connecting to Low Speed Winding
When reconnected for low speed operation they slow down rapidly. The deceleration time from 3600 to 1800 is not identical but is similar to the acceleration time from 1800 to 3600.
As David has stated, the motor is regenerating during this period.
respectfully
RE: Decelerate 2 Speed Motor by Connecting to Low Speed Winding
"Generating power"? That's not likely. The work being done (torque being produced to change the rotational speed) is simply in the opposite direction.
RE: Decelerate 2 Speed Motor by Connecting to Low Speed Winding
Think "Induction generator".
respectfully
RE: Decelerate 2 Speed Motor by Connecting to Low Speed Winding
Negtive torque on the motor shaft equals power flowing back into the source. That is assuming, of course, that the motor has excitation voltage on it.
RE: Decelerate 2 Speed Motor by Connecting to Low Speed Winding