Electrical Fundamentals: Delta Configuration and Single-Phase Induction Motors

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What is the ratio of increase in phase voltage when connected to a delta configuration?

√3 (correct)
2
1/√3
√2

What is the main difference between single-phase and polyphase induction motors?

The size of the motor
The rotation of the stator field (correct)
The type of voltage used
The number of windings in the stator

What is the principle behind the rotation of the rotor in a single-phase induction motor?

Lenz's law
Fleming's right-hand rule
Electromagnetic induction (correct)
Faraday's law of induction

What would happen to the magnetic field if the rotor is rotated by an outside force?

The magnetic field would change direction (B) Signup and view all the answers

What is the relationship between the rotor field and the stator field in a single-phase induction motor?

They are in the opposite direction (A) Signup and view all the answers

What is the main advantage of single-phase induction motors?

They are the least expensive and require the least maintenance (D) Signup and view all the answers

What is the angular spacing between individual phase windings around the stator?

120° (C) Signup and view all the answers

What is the direction of the resultant magnetic field rotation during a three-phase cycle?

Clockwise (B) Signup and view all the answers

At point 1, what is the characteristic of the magnetic fields in coils 2-2A and 3-3A?

Weaker magnetic fields (C) Signup and view all the answers

What is the purpose of the left-hand rule in determining the electromagnetic polarity of the poles?

To determine the polarity of the poles at a given instant (A) Signup and view all the answers

What is the assumption made in explaining rotor movement using the diagram?

A bar magnet is mounted in the centre of the stator and is free to rotate (A) Signup and view all the answers

What is the total angular displacement of the magnetic field after completing one full three-phase cycle?

360° (A) Signup and view all the answers

What is the purpose of the capacitor in the starting circuit of a capacitor start split-phase motor?

To create a 90° electrical phase difference between the two windings (A) Signup and view all the answers

What is the effect of the currents in the main and auxiliary windings being 90° out of phase?

The motor produces a rotating magnetic field (D) Signup and view all the answers

What happens to the starting winding when the motor reaches nearly full speed?

It is cut out by a centrifugal device (D) Signup and view all the answers

What is the purpose of the centrifugal device in the capacitor start split-phase motor?

To disconnect the starting winding at nearly full speed (C) Signup and view all the answers

What is the effect of the inductive reactance (XL) of the main winding?

It causes the current to lag the line voltage by 45° (D) Signup and view all the answers

What is the phase shift between the currents in the main and auxiliary windings?

90° (A) Signup and view all the answers