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From the ordinary A.C. mains - you can't.
The induction motor tries to run at a speed determined by the AC mains frequency supplied to it - in the U.S. it's trying to run at some fraction of 3600 r.pm., here in Australia, it's some fraction of 3000 r.p.m.
The problem is that the motor relies on the stationary winding (stator)'s magnetic field inducing an opposing magnetic field in the rotating rotor. This can only happen if there is a slight speed difference between the two magnetic fields - this is "slip".
Slip increases with increasing load - the motor slows when you load it.
High-tech motor controllers create a variable-frequencysupply. Such controllers can output an AC supply at a higher frequency than the mains, so it's possible to make the motor run above its "nameplate" speed.
This is not usually done - the rotor is designed for a maximum r.p.m., higher r.p.m.s pose the risk of destroying the rotor due to excessive "centrifugal" forces.
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What are convectional and non convectional methods of speed control of a induction motor?
The flux control method is the convectional and the non-convectional method of speed control of an induction motor.
Explains why a 3-phase induction motor develops no torque when running at synchronous speed?
When rotor speed becomes equal to Synchronous speed in an induction motor, it means that the slip is zero. Which means that there is no cutting of magnetic lines by rotor bars and hence no torque is generated. To generate Torque, rotor speed should always be less than the synchronous speed. That is why, you must have seen in your dailty life that all induction motors are rated below 3000 RPM(sync speed for a 2 pole machine). Sync speed (Ns) = 120f/P
Why is the speed of synchronous motor is more then induction motor?
Synchronous motors run at synchronous speed. An induction motor that has the same number of poles must run at a sub-synchronous speed to create a second magnetic field (a field that is at a different phase angle) to generate torque.
What is the speed of DC series motor at no load?
No load speed is the speed that the motor run when it has no load, i.e., the motor is separated from the engine, that speed is than greater than the rated speed, because the rated speed is the speed whwn the motor are linked to the load and it is the full load.
What in slip speed control?
slip speed control refers to induction machines s=(synchronous speed-motor speed)/synchronous speed by varying slip the machine can be either be operate in generated mode or motor mode
Can you make a generator out of a motor if not why not?
u can make it run but not the induction ones. For that u need to run the machine above the rated speed
Which motor rotate above synchronous speed?
An induction motor rotating at higher than synchronous speed would be generating power, thus would be a generator. No motor operating as a motor runs above synchronous speed.
Can 3 phase induction motor work when one phase is failed?
yes the motor will rotate but less then the rated speed and more heat will be desipated
Speed of the stator field of an Induction motor is?
synchronous speed
What are the advantages of induction motor?
1. Induction motor has high starting torque, therefore use for operate pump which need high starting torque. 2. Induction motor operate on variable speed. 3. It can be used as generator when speed of motor is higher than synchronous speed.
Full load torque of induction motor?
full load torque is the torque which produces rated power at full speed
Does a induction motor need excitation?
The induction motor is the special kind of motor which runs below and above the synchronous speed. which the synchronous motor runs nearly equal the synchronous speed. The operation of synchronous motor runs with dc field excited hence separate dc field current is given to the field circuit. where as the induction motor the field and main field is drawn from the same supply hence no excitation is required. But due to this separate starting mechanism has to be required in case of the single phase induction motor.
Application of induction motor in industry?
Induction motor used in industries for variable speed machines . Induction motor has always lagging power factor. Less cost compared to syn. Motor.
Difference between induction motor and induction generator?
in case of induction motor the rotor speed is less than synchronous speed giving positive slip but in case of generator the rptor speed is greater than synchronous speed giving negative slip.......
What are convectional and non convectional methods of speed control of a induction motor?
The flux control method is the convectional and the non-convectional method of speed control of an induction motor.
If a three phase induction motor runs at a speed greater than synchronous speed?
When an induction motor is pushed over synchronous speed it will become a generator and will deliver power back to the utility.
What will happen if you run induction motor beyond its rated speed?
The windings will heat up and evntually be destroyed due to the high rate of speed which induces more ccurrent in the windings
