What are slots in induction motor?
There are two types of slots, used in ac machines; these are open type and semi-enclosed type. Semi-enclosed slots are usually preferred for induction motors. An induction motor with semi-enclosed slots has low tooth pulsation loss, less noise, less magnetising current and reduced overload capacity.
What are slots in stator?
In general two types of stator slots are employed in induction motors viz, open slots and semi closed slots. Operating performance of the induction motors depends upon the shape of the slots (i) Open slots: In this type of slots the slot opening will be equal to that of the width of the slots.
What is a slot in DC motor?
The rotor of the type of DC motor we usually see has a lamination of slotted thin steel sheets (silicon steel plates), and the coil is inserted into the core slots. The minimum number of slots required to allow the rotor to rotate from any angle is three.
How many slots does a 3-phase motor have?
The stator of a 3-phase induction motor has 4 slots per pole phase.
How many RPM is a 4 pole motor?
A four-pole motor will only rotate at 1,800 rpm. For 50 Hz motors, the speed is 3,000 rpm with 2 poles, and 1,500 rpm with 4 poles.
What is a pole in motor?
The pole count of a motor is the number of permanent magnetic poles, north and south, on the rotor. There is always the same number of north and south poles on the rotor. For example, in a 12 pole motor, there are 6 north poles and 6 south poles. This motor would also be considered a 6 pole-pair motor.
How many slots does a stator have?
Stator slots will usually be a multiple of 6. The exception may be slow speed motors which may be a fractional slot configuration. Generally speaking, as the torque rating (horsepower/speed) goes up, the number of stator slots goes up.
What is the main cause of tooth pulsation loss?
Explanation: The pulsation losses occurs in the pole faces and teeth. The pulsation losses are aggravated if the air gap is small compared with slot openings. 5. The slotting produces harmonic fields which cause high frequency losses near the gap surface.
What is the use of the slot in the rotor?
The rotor is a cylindrical core made of steel lamination with slots to hold the wires for its 3-phase windings which are evenly spaced at 120 electrical degrees apart and connected in a ‘Y’ configuration.
What slots are used in DC machines?
Open slots are used in dc machine armature because.
What is 2 pole and 4 pole motor?
What is the difference between 2-Pole Motor and 4-Pole Motor? 2 pole motor has two poles (or a single pair of magnetic poles) while 4 pole motors have four magnetic poles in alternating order. 2 pole motors have twice the speed of a 4 pole motor.
What is meant by slot less motor?
Slotless motors are designed to optimize smoothness and create predictable torque output with minimal non-linear effects. Commonly referred to as slotless motors when rotary and air core motors when linear, slotless motor designs place only copper phase coils in the air gap of the motor.
How can you tell how many slots a motor has?
To answer, we need to know how many poles per phase. If 2 poles per phase, then 2 poles x 3 phases x 3 slots = 18. If 4 poles per phase then 36. etc.
What is back EMF in motor?
back EMF in Electrical Engineering
Back EMF is the system in the coil of an electric motor that opposes the current flowing through the coil, when the armature rotates. When the speed varies, the winding characteristics may fluctuate, resulting in variation of back EMF.
What is a 2 pole 3-phase motor?
On a three-phase motor the pole pattern has to be repeated for each phase. Therefore a 2=pole, 3-phase motor will have six poles.