For a constant emf, if field current is reduced then the speed of the DC motor will_____(a) Remains same(b) Increases(c) Decreases(d) Can’t sayThe question was asked in an interview for internship.My question comes from EMF and Torque Production topic in chapter Circuit Model, Emf and Torque of DC Machines

For a constant emf, if field current is reduced then the speed of the

1.	For a constant emf, if field current is reduced then the speed of the DC motor will_____(a) Remains same(b) Increases(c) Decreases(d) Can’t sayThe question was asked in an interview for internship.My question comes from EMF and Torque Production topic in chapter Circuit Model, Emf and Torque of DC Machines
Answer» Correct OPTION is (b) Increases To explain I WOULD say: When the FIELD current is reduced, the field produced by the field winding also reduces. Thus, the term Φ from the emf equation also decreases. For all other parameters kept CONSTANT speed of the DC machine is inversely proportional to field. Hence, speed of DC motor will increase.

Discussion

No Comment Found

Related InterviewSolutions

What is the armature current for a DC motor if terminal voltage is 255V and open circuit voltage is equal to 250V, where armature resistance is 0.05Ω?(a) 10A(b) 100A(c) 1KA(d) 1AThis question was posed to me in my homework.Query is from Electromagnetic Power and Circuit Models in section Circuit Model, Emf and Torque of DC Machines
When torque of the electromagnetic origin is in the direction of rotation of armature, machine is said to be operating in which of the following mode?(a) Depends on other parameters(b) Generating(c) Motoring(d) InducingI had been asked this question by my college director while I was bunking the class.This question is from Electromagnetic Power and Circuit Models in chapter Circuit Model, Emf and Torque of DC Machines
What is the armature current for a DC generator if terminal voltage is observed to be 245V and open circuit voltage is equal to 250V, where armature resistance is 0.05Ω?(a) 10A(b) 100A(c) 1KA(d) 1AThis question was posed to me by my college professor while I was bunking the class.Question is taken from Electromagnetic Power and Circuit Models topic in division Circuit Model, Emf and Torque of DC Machines
For a DC generator feeding 100kW power into 230V mains, having armature resistance and field resistance equal to 0.08Ω and 115Ω resp. The value of armature current is_____(a) 436.8 A(b) 434.8 a(c) 432.8 A(d) Data insufficientThe question was asked in an online interview.This is a very interesting question from Electromagnetic Power and Circuit Models topic in section Circuit Model, Emf and Torque of DC Machines
When torque of the electromagnetic origin is in the opposite direction of rotation of armature, machine is said to be operating in which of the following mode?(a) Depends on other parameters(b) Generating(c) Motoring(d) InducingThe question was posed to me by my school teacher while I was bunking the class.This key question is from Electromagnetic Power and Circuit Models topic in portion Circuit Model, Emf and Torque of DC Machines
Simple equation of DC machine operating in generating mode, with non-zero Ra value is________(a) Vt = Ea – Ia/Ra(b) Vt = Ea + Ia*Ra(c) Vt = – Ea + Ia*Ra(d) Vt = Ea – Ia*RaI have been asked this question in an internship interview.This intriguing question originated from Electromagnetic Power and Circuit Models in division Circuit Model, Emf and Torque of DC Machines
When Ea
Product of torque and mechanical angular velocity ω is_____(a) Ea/ω(b) Ea*Ia(c) ω/Ea(d) Can’t tellI had been asked this question at a job interview.My doubt stems from Electromagnetic Power and Circuit Models topic in portion Circuit Model, Emf and Torque of DC Machines
For an ideal DC machine, which phenomenon will reduce the terminal voltage?(a) Armature reaction(b) Commutation(c) Armature ohmic losses(d) All will contribute in reducing the terminal voltageI have been asked this question in quiz.Origin of the question is EMF and Torque Production topic in division Circuit Model, Emf and Torque of DC Machines
In a DC machine, what is the torque induced beyond the pole shoes?(a) 0(b) 2/π *∅*i(c) π *∅*i/2(d) Can’t be calculatedThe question was posed to me during an internship interview.I want to ask this question from EMF and Torque Production in division Circuit Model, Emf and Torque of DC Machines

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment