Table of Contents
- 1 Why slots on the rotor of induction motor are skewed?
- 2 What is the use of the slot in the rotor?
- 3 What is skew angle in rotor?
- 4 What is cogging and crawling?
- 5 Which type of slots are generally used in induction motor?
- 6 Why the rotor slots are not made parallel to the shaft?
- 7 What are the types of indinduction motor rotor?
- 8 Which type of induction motor has good performance but poor running performance?
Why slots on the rotor of induction motor are skewed?
The rotor or stator slot of the induction motor skewed through some angle so that the bars lie under alternate harmonic poles of the same polarity or other words, bars must be skewed through two pitches. The main purpose of skewing is to reduce the magnetic logging between the starter and the rotor.
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.
Which slots are used in the rotor of an induction motor?
01․ Which slots are used in the rotor of an induction motor? Open slots.
Why is the rotor made of copper?
Copper’s higher electrical conductivity allows the rotor to conduct electricity more efficiently, resulting in lower resistive losses and lower operating temperature. A more compact and lighter machine is possible, and the rotor more easily fits into a monoblock motor system.
What is skew angle in rotor?
In Squirrel cage rotor, slots in lamination or rotor core is not made parallel to the rotor shaft. A slight angle is maintained due to some advantages. This is called the rotor Skew. Skew helps to make the motor run quietly by reducing the magnetic hum.It reduce rotor locking tendency.
What is cogging and crawling?
October 27, 2020 February 24, 2012 by Electrical4U. The important characteristics normally shown by a squirrel cage induction motors are crawling and cogging. These characteristics are the result of improper functioning of the motor that means either motor is running at very slow speed or it is not taking the load.
Why induction motor has large number of slots?
The large number of slots in induction motor * a) Provides better overload capacity.
What is the use of the slot in the rotor Mcq?
Clarification: The rotors slots are used for inserting the field windings.
Which type of slots are generally used 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.
Why the rotor slots are not made parallel to the shaft?
The main reason for using a skewed rotor is to prevent the Cogging. In simple words, Cogging is the phenomenon of the magnetic locking between Stator and Rotor of Induction Motor. This magnetic locking occurs when the number of stator slots is equal to the number of rotor slots.
What is copper rotor motors?
Copper rotor motors are 1 to 20 horsepower, basic alternating current induction motors with a reduced-loss copper rotor.
What is the difference between copper winding and Aluminium winding?
Aluminium is more flexible than copper making it easier to wind in production processes. The higher resistivity of aluminium gives inherently lower eddy losses in the windings. This mitigates the risk for hot spots.
What are the types of indinduction motor rotor?
Induction motor rotor is of two types: Squirrel Cage Rotor. In this type of rotor, the rotor winding consists of conductors, in form of copper or aluminum bars embedded in semi-closed slots of a laminated rotor core.
Which type of induction motor has good performance but poor running performance?
By seeing the above points, we can conclude that “due to the provision of an extra resistor, Wound Type Rotor or Slip Ring Type Rotor type of induction motor has good stating performance but poor running performance “ Electrical4U is dedicated to the teaching and sharing of all things related to electrical and electronics engineering.
Why are the rotors of a power pole motor skewed?
To prevent undesirable pulsation of reluctance. slots are skewed by an angle that is sufficient to prevent harmonic emf in each rotor bars inserted into rotor slots. In general to eliminate n’th harmonic of “p” pole motor.
What is the advantage of semi closed slot in induction motor?
Semi closed slots are preferred for induction motors because with their use the gap contraction factor is small giving a small value of magnetizing current. The use of semi enclosed slots results in low tooth pulsation loss and a much quieter operation as compared with that with openslots.