Which type of rotor is used in induction motor?
Table of Contents
- 1 Which type of rotor is used in induction motor?
- 2 Why skewed type rotor construction is always preferred?
- 3 What are rotor bars used for?
- 4 Which induction motors are available in copper bars?
- 5 Why are the rotor bars skewed?
- 6 What are induction motors used in?
- 7 How many rotor bars does my motor have?
- 8 What are the types of indinduction motor rotor?
- 9 What are the advantages of using copper in motor rotors?
- 10 Why does current flow through the rotor bars of induction motor?
Which type of rotor is used in induction motor?
Induction motor rotors may be of two types, wound rotor or squirrel-cage rotor. A wound rotor has windings similar to and wound for the same number of poles as the stator. The rotor windings are connected to insulated slip rings mounted on the rotor shaft.
Why skewed type rotor construction is always preferred?
Rotor conductors are skewed because of the following reasons: Primarily to prevent the Cogging Phenomenon. It is a phenomenon in which, if the rotor conductors are straight, there are chances of magnetic locking or strong coupling between Rotor & Stator.
Why are induction motors most commonly used?
Three-phase squirrel-cage induction motors are widely used as industrial drives because they are self-starting, reliable and economical. Although traditionally used in fixed-speed service, induction motors are increasingly being used with variable-frequency drives (VFD) in variable-speed service.
What are rotor bars used for?
The interaction of the magnetic fields of currents in the stator and rotor produce a torque on the rotor. By adjusting the shape of the bars in the rotor, the speed-torque characteristics of the motor can be changed, to minimize starting current or to maximize low-speed torque, for example.
Which induction motors are available in copper bars?
5 H.P., 50-Hz, 3-phase, 440 V, induction motors are available for the following r.p.m.Which motor will be the costliest?…
| Q. | In three-phase induction motors sometimes copper bars are placed deep in the rotorto |
|---|---|
| A. | improve starting torque |
| B. | reduce copper losses |
| C. | improve efficiency |
Why are rotor bars skewed in induction?
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.
Why are the rotor bars skewed?
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 are induction motors used in?
Used in almost every process, induction motors are mainly used in water pumps, kitchen appliances, fans and air conditioners, automobiles and common industrial machinery like boiler pumps and compressors.
Why copper bars in induction motor are shorted?
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. To facilitate a closed path in the rotor circuit, both sides of the rotor bars are short-circuited by end rings.
How many rotor bars does my motor have?
One other method to determine the number of rotor bars it to examine the the RBPF +/- K*2LF pattern in vibration: take vibration using high Fmax (above RBPF) and high # lines (to get good frequency resolution) – something like Fmax=300,000, lines =6400. Look for the set of peaks separated by by 2*LF.
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.
Why are induction motors made of copper?
The use of copper for the conductor bars and end rings of induction motors in place of aluminum results in attractive improvements in motor energy efficiency.
What are the advantages of using copper in motor rotors?
Copper Motor Rotor. The use of copper for the conductor bars and end rings of induction motors in place of aluminum results in attractive improvements in motor energy efficiency.
Why does current flow through the rotor bars of induction motor?
When an induction motor is started and load is not engaged with the motor, there is hardly any current that flows through the rotor bars. As you increase the load, gradually more and more currents starts flowing through the rotor bars. There are several ways of explaining the phenomenon.