φA DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%.

Electrical Machines
φA DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%.

940 RPM

970 RPM

960 RPM

920 RPM

940 RPM

970 RPM

960 RPM

920 RPM

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Electrical Machines
If iron loss and full load copper loss of any transformer are denoted by Pi and Pc, then the load corresponding to maximum efficiency is given by

(Pi / Pc) Ãƒâ€” full Load.

(Pi / Pc)0.5 Ãƒâ€” Full Load.

(Pi / Pc)1.6 Ãƒâ€” full Load.

(Pi / Pc)2 Ãƒâ€” full Load.

(Pi / Pc) Ãƒâ€” full Load.

(Pi / Pc)0.5 Ãƒâ€” Full Load.

(Pi / Pc)1.6 Ãƒâ€” full Load.

(Pi / Pc)2 Ãƒâ€” full Load.

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Electrical Machines
Compensating winding is placed in the

pole shoe

All of these

main field

armature core

pole shoe

All of these

main field

armature core

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Electrical Machines
Armature reaction depends on which of the following?

power factor of load

both 1 and 2

magnitude of load current

None of these

power factor of load

both 1 and 2

magnitude of load current

None of these

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Electrical Machines
A transformer has maximum efficiency at 3/4 load. The ratio of iron loss and full load copper loss is

9/16.

4/3.

16/9.

3/4.

9/16.

4/3.

16/9.

3/4.

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Electrical Machines
Which of the following motor is used in grinders?

Split phase IM.

Capacitor start capacitor run IM.

Capacitor start IM.

Synchronous motor.

Split phase IM.

Capacitor start capacitor run IM.

Capacitor start IM.

Synchronous motor.

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Electrical Machines

Electrical Machines φA DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%.

Electrical Machines If iron loss and full load copper loss of any transformer are denoted by Pi and Pc, then the load corresponding to maximum efficiency is given by

Electrical Machines Compensating winding is placed in the

Electrical Machines Armature reaction depends on which of the following?

Electrical Machines A transformer has maximum efficiency at 3/4 load. The ratio of iron loss and full load copper loss is

Electrical Machines Which of the following motor is used in grinders?

Electrical Machines
φA DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%.

Electrical Machines
If iron loss and full load copper loss of any transformer are denoted by Pi and Pc, then the load corresponding to maximum efficiency is given by

Electrical Machines
Compensating winding is placed in the

Electrical Machines
Armature reaction depends on which of the following?

Electrical Machines
A transformer has maximum efficiency at 3/4 load. The ratio of iron loss and full load copper loss is

Electrical Machines
Which of the following motor is used in grinders?