AnswersDriveThe stator of an induction motor consists of poles carrying supply current to induce a magnetic field that penetrates the rotor. To optimize the distribution of the magnetic field, windings are distributed in slots around the stator, with the magnetic field having the same number of north and south poles.
Besides, what is the difference between a 2 pole and 4 pole motor?
A 4-pole motor is with 4 magnetic poles on the rotor and the number of related electro-magnetic windings (circuits.) A 4-pole motor has about 3.0 ft.-lbs of torque per horsepower where a 2-pole motor has 1.5 ft.-lbs of torque. At 60 Hz, a 4-pole motor is about 1800 rpm where a 2-pole motor is 3600 rpm.
What is the rpm of a 6 pole motor?
| Approximate Electrical Motor Speed (rpm) | ||
|---|---|---|
| No. Poles | Speed with Rated Load | Synchronous Speed (no Load) |
| 4 | 1725 | 1800 |
| 6 | 1140 | 1200 |
| 8 | 850 | 900 |
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What is a pole in induction motor?
The stator of an induction motor consists of poles carrying supply current to induce a magnetic field that penetrates the rotor. Induction motors are most commonly run on single-phase or three-phase power, but two-phase motors exist; in theory, induction motors can have any number of phases.
2
How can we control the speed of induction motor?
There are several ways to control the speed of an induction motor.
- Reduce the voltage applied to the motor.
- Control the current to the motor.
- Use a wound-rotor motor and control the resistance applied to the rotor windings.
- Control the frequency and voltage applied to the motor.
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What is the synchronous speed of a 6 pole motor?
The rotation speed will be 1/6 of the electrical speed of the AC. Rotor speed will be 1/6 of that experienced with a 2-pole synchronous motor. Example: 60 Hz would rotate a 2-pole motor at 3600 rpm, or 600 rpm for a 12-pole motor. The stator (Figure above) shows a 12-pole Westclox synchronous clock motor.
4
Why a single phase induction motor is not self starting?
Rotating magnetic field, there are minimum two phases required. But in the case of single phase induction motor, there is a single phase. Hence, not self starting. When stator winding of a Single Phase Induction Motor is connected to a sinusoidally alternating voltage source, the stator flux alternates in a space.
5
What is the difference between a 2 pole and 4 pole motor?
A 4-pole motor is with 4 magnetic poles on the rotor and the number of related electro-magnetic windings (circuits.) A 4-pole motor has about 3.0 ft.-lbs of torque per horsepower where a 2-pole motor has 1.5 ft.-lbs of torque. At 60 Hz, a 4-pole motor is about 1800 rpm where a 2-pole motor is 3600 rpm.
6
Why a three phase induction motor is self starting?
Consider a 3-phase induction motor: A 3- phase supply to the armature produces a rotating magnetic field. This flux being linked to the rotor coils, induces voltage and produces current in the rotor. The current carrying rotor being placed in a magnetic field, experiences a torque and hence begins to rotate.
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What is the speed of a 2 pole motor?
Motor Synchronous Speeds (RPM)
| Frequency | Number Of Poles | |
|---|---|---|
| 2 | 4 | |
| 60-cycles | 3600 | 1800 |
| 50-cycles | 3000 | 1500 |
8
What is a three phase induction motor?
The stator of an induction motor consists of a number of overlapping windings offset by an electrical angle of 120°. When the primary winding or stator is connected to a three phase alternating current supply, it establishes a rotating magnetic field which rotates at a synchronous speed.
9
What is 3 phase?
Three-phase electric power is a common method of alternating current electric power generation, transmission, and distribution. It is a type of polyphase system and is the most common method used by electrical grids worldwide to transfer power. It is also used to power large motors and other heavy loads.
10
Why the synchronous motor is not self starting?
This is because the speed with which rotating magnetic field is rotating is so high that it is unable to rotate the rotor from its initial position, due to the inertia of the rotor. So under any case, whatever may be the starting position of the rotor, synchronous motor is not self starting.
11
What is a squirrel cage induction motor?
A squirrel-cage rotor is the rotating part of the common squirrel-cage induction motor. It consists of a cylinder of steel laminations, with aluminum or copper conductors embedded in its surface. The interaction of the two sources of magnetic field produce torque on the rotor.
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What is meant by induction motor?
Definition of induction motor. : an alternating-current motor in which torque is produced by the reaction between a varying magnetic field generated in the stator and the current induced in the coils of the rotor.
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What is a double pole switch used for?
Poles: A switch pole refers to the number of separate circuits that the switch controls. A single-pole switch controls just one circuit. A double-pole switch controls two separate circuits. A double-pole switch is like two separate single-pole switches that are mechanically operated by the same lever, knob, or button.
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What is the back EMF?
Counter-electromotive force (abbreviated counter EMF or simply CEMF), also known as back electromotive force (or back EMF), is the electromotive force or "voltage" that opposes the change in current which induced it.
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What are the different types of induction motors?
There are single phase and three phase induction motors. By far, the most common type of three phase motor is the squirrel cage motor, but there are also wound rotor motors (also called slipring motors). Squirrel cage motors have different torque vs. speed design types.
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How does 3 phase induction motor work?
The Working of an Induction Motor. Fig.7 Squirrel cage rotor which is the most commonly used one in induction motors. A 3 phase AC current passing through a Stator winding produces a rotating magnetic field. So as in the previous case, current will be induced in the bars of the squirrel cage and it will start to rotate
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Why slip ring induction motor is used?
A wound rotor induction motor has a stator like the squirrel cage induction motor, but a rotor with insulated windings brought out via slip rings and brushes. However, no power is applied to the slip rings. Their sole purpose is to allow resistance to be placed in series with the rotor windings while starting.
18
What are the different types of single phase induction motor?
Now depending upon these additional means the single phase induction motors are classified as:
- Split phase induction motor.
- Capacitor start inductor motor.
- Capacitor start capacitor run induction motor (two value capacitor method).
- Permanent split capacitor (PSC) motor .
- Shaded pole induction motor.
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What is the speed of the rotor?
This rotor rotates at a speed less than the stator rotating magnetic field or synchronous speed. Rotor slip provides necessary induction of rotor currents for motor torque, which is in proportion to slip. When rotor speed increases, the slip decreases.