Can we add extra resistance in series with squirrel cage rotor? State the reason?

Can we add extra resistance in series with squirrel cage rotor? State the reason?
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1 Answer

Answer :

We cannot add extra resistance in series with the rotor because all the copper bars of the rotor are short circuited in both the sides by copper end rings to have a closed circuit.
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Description : State the condition for maximum running torque?

Last Answer : R2=sX2

State the condition for maximum starting torque?

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State the principle of 3 phase IM?

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State the types of Induction motor ?

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A double squirrel-cage motor is designed to have __________. A. low starting torque B. low starting current C. high starting voltage D. low starting resistance

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Explain the operation of induction motor in simple words?

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Why Speed Control of Induction Motor is difficult compared to DC shunt motor?

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Why the efficiency of the Induction motor is less compared to transformer?

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Last Answer : Answer: Induction motor and Transformer operates on the same principle that power is transferred to secondary by mutual induction. But in transformer, flux will be traveled from primary to ... compared to transformer which also results in less efficiency for induction motor compared to transformer.

Disadvantages of Star-Delta Starting of Induction motor?

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Last Answer : In Star-Delta starting induction motor stator is connected in star connection for starting after picking up speed it is connected to delta connection. When induction motor is connected in star connection ... . This also results in reduced starting torque (1/3 times compared to delta connection).

What is the condition for maximum torque in induction motor?

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Last Answer : Starting torque will be maximum when the rotor resistance / phase is equal to standstill rotor reactance / phase

What are the advantages and disadvantages of Induction Motors?

Description : What are the advantages and disadvantages of Induction Motors?

Last Answer : Advantages: It is simple and rugged in construction It is relatively cheap Induction motors require less maintenance Induction motor has high efficiency and reasonably good power factor 3-phase induction ... and its speed cannot be changed easily Its starting torque is inferior to dc shunt motor

Induction Motor Operating Characteristics

Description : Induction Motor Operating Characteristics

Last Answer : All torques of an induction motor, at a given slip, vary approximately as the square of the voltage applied to its terminals Low rotor resistance results in high full load speed (low slip), ... voltage), the load torque is unchanged, and the ratio of accelerating torque to load torque is reduced

why the three phase induction motor draws heavy current at starting?

Description : why the three phase induction motor draws heavy current at starting?

Last Answer : At the time of starting, the rotor speed is zero hence slip is 1, the emf induced in rotor winding is very high. Hence rotor current is also very high. The starting current is 5 to 7 times more than its full load current.

What happens if the air gap flux density in an induction motor increases?

Description : What happens if the air gap flux density in an induction motor increases?

Last Answer : The increase in air gap flux increases iron loss and hence efficiency decreases.

What would happen if a 3 phase induction motor is switched on with one phase disconnected?

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Last Answer : The motor is likely to burn .

In what respect does a 1-phase Induction motor differ from a 3-phase Induction motor?

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Last Answer : Construction wise a plain 1-phase Induction motor is more or less similar to a 3-phase squirrel-cage Induction motor except that its stator is provided with only 1-phase winding..

What are the methods adopted to reduce harmonic torques?

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Last Answer : The methods used for reduction or elimination of harmonic torques are chording, integral slot winding, skewing and increasing the length of air gap.