Virtual Labs

Electrical Engineering Virtual Power Lab Experiments

Aim

Theory

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Procedure

Simulation

Posttest

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Aim

Theory

Pretest

Procedure

Simulation

Posttest

References

Feedback

Study of Induction Motor Protection Using a Numerical Relay

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1. In textile machines, to avoid breaking of threads, soft starters are used. The commonly used method in soft starter is:

a: Direct online method Explanation

Explanation

b: Star-delta method Explanation

Explanation

c: Thyristor voltage controller method Explanation

Explanation

d: Thyristor current controller method Explanation

Explanation

2. Torque of an induction motor can sometimes be given in synchronous-watt. One synchronous-watt is equal to:

a: 60 / (2 * pi * Ns) N-m Explanation

Explanation

b: (2 * pi * Ns) / 60 N-m Explanation

Explanation

c: 120 / (2 * pi * Ns) N-m Explanation

Explanation

d: (2 * pi * Ns) / 120 N-m Explanation

Explanation

3. The air gap flux of induction motor does not contain:

a: 2nd harmonics Explanation

Explanation

b: 3rd harmonics Explanation

Explanation

c: 5th harmonics Explanation

Explanation

d: 7th harmonics Explanation

Explanation

4. L&T MPR 300 protection relay used for induction motor protection is an:

a: Analog electronic relay Explanation

Explanation

b: Digital relay Explanation

Explanation

c: Both (a) and (b) Explanation

Explanation

d: none of the above Explanation

Explanation

5. MPR300 protection relay is used for:

a: Single phase induction motors Explanation

Explanation

b: Fractional hp induction motors Explanation

Explanation

c: 3-phase induction motors upto 85 hp rating Explanation

Explanation

d: 3-phase induction motors above 85 hp rating Explanation

Explanation

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