Electrician 3rd sem Alternator

Which formula is used to calculate EMF/phase in a ideal alternator?

Which rule is used to find the direction of induced emf in an alternator?

• Cork screw rule

• Right hand palm rule

• Fleming’s left hand rule

• Fleming’s right hand rule

What is the name of the part of alternator?

• Stator

• Exciter

• Salient pole rotor

• Smooth cylindrical rotor

What is the formula to calculate emf equation of an alternator?

• E = 4.44 Kd Kc T ɸm

• E = 2.22 Kd Kc Fɸm

• E = 4.44 Kd Kc FT ɸm

• E = 1.11 Kd Kc F ɸm

How alternators are rated?

• KVA

• KW

• MW

• KV

Which formula is used to calculate the percentage voltage regulation in alternator?

What is the supply frequency of an alternator having 6 poles runs at 1000 rpm?

• 25 Hz

• 40 Hz

• 50 Hz

• 60 Hz

Calculate the speed of an alternator having 2 poles at a frequency of 50 Hz?

• 1500 rpm

• 2500 rpm

• 3000 rpm

• 6000 rpm

What condition the lamps become dark in dark lamp method of parallel operation of two alternators?

• A Terminal voltages are equal

• Voltage and frequency are equal

• Voltage and power rating are equal

• Frequency are same in both alternator

How to compensate de-magnetizing effect due to armature reaction in an alternator?

• Reducing the speed of alternator

• Reducing field excitation current

• Increasing field excitation current

• Increasing the speed of alternator