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Efficiency of a motor is the ratio of power supplied to it, to the power produced by it, expressed as a percentage. This varies from motor to motor. It is calculated using the equation: efficiency = ((Pin - Pout) / Pin) * 100
A typical power conversion efficiency for an induction motor over ½ HP would be 90%
CommentEfficiency is actually the ratio of output power to input power, not the other way around!
Wiki User
∙ 11y ago
Wiki User
∙ 10y agoAC motors can be made to go at different speeds. Synchronous motors run at 50 revs per second on 50 Hz or 60 revs per second on 60 Hz. They can also be made to run at half those speeds or lower speeds. Induction motors usually run at about 90-95% of the synchronous speed.
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The equation for RPM is RPM = Hz x 60 x 2/number of poles in the motor.
A four pole motor at 60 HZ would be 60 x 60 x 2 / 4 = 7200/4 = 1800 RPM.
A four pole motor at 50 HZ would be 50 x 60 x 2 / 4 = 6000/4 = 1500 RPM.
Wiki User
∙ 12y agoAn induction motor will always spin at a slightly slower speed than the power system frequency suggests it should. This difference in speed is used to generate torque in the motor, and is directly related to the loading of the motor (the more load, the larger the frequency difference). The synchronous speed is the speed the motor would be turning at if it was perfectly in phase with the power system.
Wiki User
∙ 13y agoNs= 120f/P, Nr=s*Ns.......where Nr is the speed of rotor in RPM, Ns in the synchronous speed, s is slip, p is number of pole, f is supply frequency.
Wiki User
∙ 13y agoThere should be a rating plate on the motor that shows a Revolution Per Minute (RPM) value. Unless you have a calibrated strobe light, that is the way to tell the speed.
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Is it necessary to have three phase rotor windings for the transmitter and motor in selsyn motor?
is it necessary to have three phase rotor
How do you use a one phase motor in place of a three phase motor?
To use a single/one phase motor instead of a three phase motor is possible if you have a three phase power supply as you will only need to tap one of the three phases together with neutral and an earthwire, however to use a three phase motor instead of a single phase will require the provision of three phase power supply.
What is locked rotor in three phase induction motor?
A motors locked rotor current is the same as the motors starting current. This is the point where the voltage is applied to a non rotating motor, time cycle zero. Because the motor is not rotation and generating a back EMF to oppose the inrush current, the current will go as high as 6 times the running current of the motor.
You switched leads on your 3phase motor and it did not reverse?
Then it is not a three phase motor.
When does a motor not need a neutral wire?
If the motor is operated from a three phase three wire distribution system the motor will not need a neutral wire.
Is it necessary to have three phase rotor windings for the transmitter and motor in selsyn motor?
is it necessary to have three phase rotor
Why single phase induction motor always runs below the synchronous speed?
For exactly the same reason as three-phase motors always run below synchronous speed. If they were to run at synchronous speed then no voltage and, therefore, no rotor current will be induced into the rotor to drive it.
What are the main parts of three phase motor?
Wire, bearings, rotor and stator.
How do you make a 9 wire three phase motor into a three speed motor?
You don't.
Is a three phase induction motor self starting?
A three-phase motor has a steady rotating magnetic field generated by the stator coil, and the rotor just follows the field.
Why sleep is occurs in three phase induction motor?
Slip is the relative difference between the speed of the rotating magnetic field of the stator windings and the speed of the rotor. The rotor must always run at a speed lower than the synchronous speed otherwise the rotor windings will not be cut by the magnetic field and hence no induced emf,no torque and the rotor will stand idle.
What is a three phase induction motor?
Induction motor is nothing but rotating transformer it works on principle of mutual induction , mainly induction motor consists of rotor and stator,stator is excited by three phase supply and rotor is shorted through resistances and slip rings. When ever stator is excited by three phase supply a rotating magnetic field running at synchronous speed is produced which in turn cuts the rotor winding causes flowing of current results in production of magnetic fields in rotor which having less than synchronous speed (slip speed), then the interaction of these stator and rotor magnetic fields produces a twisting moment in the rotor called synchronous speed
What is the principle of 3 phase induction motor?
When three phase supply is given to the three phase stator winding of the induction motor,a rotating magnetic field is developed around the stator which rotates at synchronous speed.This rotating magnetic field passes through the air gap and cuts the rotor conductors which were stationary.Due to the relative speed between the stationary rotor conductors and the rotating magnetic field,an emf is induced in the rotor conductors.As the rotor conductors are short circuited, current starts flowing through it.And as these current carrying rotor conductors are placed in the magnetic field produced by the stator, they experiences a mechanical force i.e. torque which moves the rotor in the same direction as that of the rotating magnetic field. the induction motor can't run at the synchronous speed because at synchronous speed the induction motor can not develop any torque to move the rotor from its stationary position.
Working principle of synchronus motor?
A synchronous motor is a three phase motor, which uses a magnetic field created by permanent magnets or a DC electromagnet on the rotor (usually). The stator windings have 3 phase voltages applied, and coupled with the DC field, create a rotating magnetic field that drives the motor at synchronous speed.
How many Slip rings in synchronous motor?
If the synchronous motor is single phase then there are two slip rings & if this motor is three phase so the slip rings are three in number. Correction; I have never seen a single phase synchronous motor. It would cost more that it was worth. A synchronous motor has a separately excited field. If the excitation comes from a stationary DC source it has 2 slip (collector) rings. A brushless induction motor has no slip rings because the exciter armature rotates and so do the rectifiers. A permanent magnet motor, used with variable frequency drives, is another type of synchronous motor that has no slip rings. A three phase motor with 3 slip rings is a Wound Rotor motor. Wound rotor motors are variable speed motors that were used for such applications as bridges and cranes before variable speed drives.
How do you wire a three phase motor with two speed?
Star and delta connection
How do you wire a three phase motor with two speed to a three phase power supply lead numbers not specified?
There are many types of winding on a two speed three phase motor. The number of wires from the motor should have been stated. This is a guess that the motor is a six lead. The diagram is for a six lead out two speed, one winding, single voltage constant horsepower motor.See sources and related link below
