Formative Electrical Machine 2-22/23

DC generator is to convert electrical energy to mechanical energy

• True

• False

The working principles of Dc Generator is?

• Faradays Induction Law

• Lenz's Law

• Ohm's Law

• Lorentz's Law

Identify the DC machine shown in the circuit

• short shunt generator

• shunt motor

• long shunt generator

• shunt generator

What does the label "?" indicate

• armature

• armature conductor

• brush

• field coil

A 240 V generator has Ia of 5A. The Ra is 0.05Ω and Rse is 0.03Ω. Calculate the generated voltage, Eg

• 239.6 V

• 240.4 V

• 240 V

• 240.25 V

DC Motor is to convert electrical energy to mechanical energy

• True

• False

DC Motor are most preferred and commonly use in daily appliances due to

• came with complicated circuit

• portable operation

• irreversible direction

• not easy to control

The back emf (Eb) is based on the Lenz's Law which Eb acts in opposite direction to the applied voltage

• True

• False

The Eb for the circuit can be expressed as....

• Eb= Vt- Ia (Ra+Rs)- Vb

• Eb= Vt- IaRa- ILRs- Vb

• Eb= Vt- IaRa- Vb

• Eb= Vt-IaRse

Referring to figure, given IL is 45A, Rsh is 50Ω, Rse is 23Ω and Vt is 600 V. Calculate Ish

• 43.2 A

• 32.7 A

• 12 A