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What is used on a single phase induction motor to disconnect the start winding after the motor starts?
Wiki User
∙ 13y ago
A centrifugal switch, once the motor reaches near run speed, centrifugal force causes a set of contacts to open and disconnect the start capacitors. Some larger motors use a contactor which is disconnected by the centrifugal switch.
Wiki User
∙ 13y ago
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What are the advantages of three phase induction motors over the other motors?
A Single phase induction motor includes a main winding, an auxiliary winding, a run capacitor, & a subsidiary star device. The auxiliary winding is configured such that the number of turns of the aauxiliary winding through which a current flows, varies according to the operating mode of motor. When the motor starts, the number of turns of the auxiliary winding through which a current flows is reduced there by increasing the start efficiency of the motor. when the motor runs in normal mode, the number of turns of auxiliary winding through which a current flows is increasing there by increasing the operations efficiency of motor
Performance curve of a single phase induction motor?
The performance curve can be a graph of torque versus speed. The torque is zero at zero speed and also at the synchronous speed. Normally an induction motor operates at 90-97% of the synchronous speed, where the slip is between 10% and 3%. In this region the torque is proportional to the slip. As the torque is increased the speed falls until the motor stalls and the speed drops to zero. Below the stalling speed the torque rises between zero speed and the stalling speed. Because the torque is 0 at 0, a single-phase induction motor needs a separate starting winding fed by a starting capacitor to produce a little positive torque that starts the motor.
How will star and delta configured three phase induction motors perform as load increases?
Motors with star delta starter, starts with star mode, avoiding inrush of current for a relatively higher starting load, as the speed picks up, it goes to Delta mode with full phase voltage applied across the winding and continues to cater to the designed load.
What will happen if induction motor is in star-star connected?
If a motor is connected in a star configuration it will operate at a slower speed. This is the working process that a star delta starter operates on. At first through the starter the motor starts in the star connection. When the motor gets up to its highest speed in that connection it times a timer out , the star starter drops out and the delta starter pulls in and then connects the motor in the delta connection. This allows more voltage to be applied to the motor and it then speeds up to its nameplate rated RPM.
What is the starting method of synchronous motor?
There are 5 types of starting in induction motors: 1) resistance variable method 2) auto transformer method 3) slip ring induction motor method Squirrel cage induction motor using two types of starting methods 1.Direct on line starter 2.Star delta starter
What is induction motor in physics?
An induction motor consists of a rotor winding and stator winding. Rotor windings are short circuited and stator winding are given electrical AC supply .Now lets do the physics behind it . As the current starts to flow in the stator winding , magnetic flux start to produce around it . due to it's alternating nature that flux varies and according to farady law emf is induced in the rotor winding .Since the rotor winding is short circuited the current circulates in it .And when a current carrying conductor is placed in magnetic field it experiances a force and hence if start to rotate.
What are the advantages of three phase induction motors over the other motors?
A Single phase induction motor includes a main winding, an auxiliary winding, a run capacitor, & a subsidiary star device. The auxiliary winding is configured such that the number of turns of the aauxiliary winding through which a current flows, varies according to the operating mode of motor. When the motor starts, the number of turns of the auxiliary winding through which a current flows is reduced there by increasing the start efficiency of the motor. when the motor runs in normal mode, the number of turns of auxiliary winding through which a current flows is increasing there by increasing the operations efficiency of motor
Performance curve of a single phase induction motor?
The performance curve can be a graph of torque versus speed. The torque is zero at zero speed and also at the synchronous speed. Normally an induction motor operates at 90-97% of the synchronous speed, where the slip is between 10% and 3%. In this region the torque is proportional to the slip. As the torque is increased the speed falls until the motor stalls and the speed drops to zero. Below the stalling speed the torque rises between zero speed and the stalling speed. Because the torque is 0 at 0, a single-phase induction motor needs a separate starting winding fed by a starting capacitor to produce a little positive torque that starts the motor.
How is the synchronous motor made self starting?
The synchronous motor is made self starting by providing a special winding on the rotor poles, known as damper winding or squirrel cage winding. AC supply given to the stator produces a rotating magnetic field which causes the rotor to rotate, therefore, in the beginning synchronous motor provided with damper winding starts as a squirrel cage induction motor. The exciter moves along the rotor. When the motor attains about 95%of synchronous speed, the rotor winding is connected to exciter terminals and the rotor is magnetically locked by the rotating field of the stator and the motor runs as a synchronous motor. While starting a synchronous motor, the field winding must be shorted through a suitable resistance so that the induced voltage is distributed throughout the whole winding and no part is subjected to the high voltage induced in the entire winding.
What is most important question for interview mechanical engineer?
How induction motor starts
How do single phase motors work?
the working principle of single phase induction motor is similar to the three phase induction motor, when we supply is given to the single phase induction motor a revolving field set up in the stator which produces a torqe air gap between north pole and south pole and rotor picks up speed
Does deduction end or start with a generalization?
Deduction STARTS with a generaliztaion! Induction ENDS with a generalization!
Can you do without a capacitor in a ceiling fan?
No, it is the capacitors effect upon the motor's winding that starts the fan to turn.
What are the standard size disconnect up to 600 amps?
The standards disconnect starts from 30, 60, 100, 200, 400, 600.
What are the advantages of three phase motor over the single phase motor?
A 3-phase motor produces a steady torque that does not pulsate. A 3-phase motor starts turning in the right direction when switched on without the need for a separate starting winding.
How will star and delta configured three phase induction motors perform as load increases?
Motors with star delta starter, starts with star mode, avoiding inrush of current for a relatively higher starting load, as the speed picks up, it goes to Delta mode with full phase voltage applied across the winding and continues to cater to the designed load.
What poem starts with a single flower?
Rose
