Recent questions tagged speed

Why does the speed of a DC shunt motor decrease as the load increases?

Describe the following errors and their compensation: (i) Phase error (ii) Speed error

A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be

The number of cycles in which a high speed circuit breaker can complete its operation is  (A) 3 to 8 (B) 10 to 18 (C) 20 to 30 (D) 40 to 50

The fall in speed of a dc generator due to increase in load can be corrected by  (1) cooling the armature.. (2) increasing the excitation. (3) reducing the load voltage. (4) increasing the input to the prime mover

The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque  (1) Decreases (2) Increases (3) Remains constant (4) None of the above

The unit of speed regulation of a governor is :  (A) Hz (B) Hz/MW (C) Hz/MVA (D) rpm/MVAR

The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ (A) directly proportional to α and Φ (B) inversely proportional to α and Φ (C) directly proportional to α and inversely proportional to Φ (D) directly proportional to Φ and inversely proportional to α

The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min (A) 100 rpm (B) 200 rpm (C) 400 rpm (D) 800 rpm

In an adjustable speed ac drive which quantity gets reduced above rated speed ? (A) developed torque (B) stator frequency (C) reduced starting torque (D) stator current

Under constant load conditions, the speed of a d.c. motor is affected by?

The speed of a D.C. motor can be controlled by varying  1. Its flux per pole 2. Resistance of armature circuit 3. Applied voltage 4. All of the above

Is the speed of alternator is directly proportional to frequency?

Salient pole rotor is use for which speed?

Which rotor is use for high speed in turbo alternators?

If we change the excitation of synchronous machine will it affect on motor speed?

An electric motor in which both stator field and rotor rotates with same speed is called?

Synchronous motor always runs at which speed?

Which motor has the best speed regulation?