The most efficient method of increasing the speed of a 3.75KW d.c. shunt motor would be ...

The most efficient method of increasing the speed of a 3.75KW d.c. shunt motor would be 

A) Armature control B) Flux control C) Ward—Leonard D) Tapped—field control
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1 Answer

Answer :

 Flux control 

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One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for polarity using a/an ____________. A. iron bar across each field B. magnetic compass placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections

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Last Answer : Answer: B

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Description : Give two basic speed control scheme of DC shunt motor?

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A d.c. shunt motor runs at no load speed of 1140 r.p.m. At full load, armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full load speed in r.p.m. is (A) 1080 (B) 1203 (C) 1000 (D) 1200

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Last Answer : (A) 1080

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Last Answer : (A) 5 to 10%

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A dc shunt generator has a speed of 800 rpm when delivering 20 A to the load at the terminal voltage of 220V. If the same machine is run as a motor it takes a line current of 20A from 220V supply. The speed of the machine as a motor will be (A) 800 rpm. (B) more than 800 rpm. (C) less than 800 rpm. (D) both higher or lower than 800 rpm.

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Last Answer : (C) less than 800 rpm.

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Description : The no load speed of a d.c. shunt motor is 1140 rpm. At full load, the armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full load speed in rpm will be: (A) 1080 (B) 1203 (C) 1000 (D) 1200

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The speed of a D.C. shunt motor can be increased by?

Last Answer : The speed of a D.C. shunt motor can be increased by increasing the resistance in field circuit.

As the load is increased the speed of D.C. shunt motor will?

Last Answer : As the load is increased the speed of D.C. shunt motor will reduce slightly.

In a D.C. shunt motor, speed is?

Last Answer : In a D.C. shunt motor, speed is independent of armature current.

The speed of a D.C. shunt motor more than its full-load speed can be obtained by?

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