18 Questions
What is dynamically induced EMF, and where is it observed?
Dynamically induced EMF is an EMF induced due to relative motion between a coil and a magnetic field. It is observed in DC generators, induction motors, back EMF in DC motors, and alternators.
What is the expression for induced EMF in dynamically induced EMF?
e = B.l.v.sinϕ
What is statically induced EMF, and how does it differ from dynamically induced EMF?
Statically induced EMF is an EMF induced without any motion, where neither the coil nor the magnet moves. It differs from dynamically induced EMF, which requires relative motion between the coil and the magnetic field.
What are the two main types of statically induced EMF?
The two main types of statically induced EMF are self-induced EMF and mutually induced EMF.
What is the expression for induced EMF in statically induced EMF?
e = -L(di/dt) or e = -N(dϕ/dt)
What is the difference between self-induced EMF and mutually induced EMF?
Self-induced EMF is the EMF induced in a coil due to its own changing magnetic flux, while mutually induced EMF is the EMF induced in one coil due to the changing magnetic flux of another coil.
What is the primary function of pole shoes in a DC machine?
To spread out the magnetic flux over the armature periphery more uniformly.
What is the role of the armature winding in a generator?
To induce emf in it.
What is the main difference between dynamically induced emf and statically induced emf?
Dynamically induced emf occurs when there is relative motion between the coil and magnetic field, whereas statically induced emf occurs when the coil is stationary and the magnetic field changes.
What is the purpose of the commutator in a DC machine?
To collect or send current to the armature winding and maintain unidirectional current in the armature winding.
What is the function of the bearings in a DC machine?
To support the rotor and reduce friction for smooth rotation of the rotor.
What is the role of the shaft in a DC machine?
To transfer mechanical power.
Under what condition is an emf induced in a conductor according to Faraday's First Law of electromagnetic induction?
Whenever a changing magnetic flux links with a conductor, or when a conductor cuts across a magnetic field.
What is the significance of the form factor in AC circuits?
It is the ratio of the RMS value to the average value of an alternating quantity.
What is the difference between dynamically induced emf and statically induced emf?
Dynamically induced emf is induced when there is a change in magnetic flux, whereas statically induced emf is induced when there is a change in magnetic field.
What is the peak factor of an alternating quantity?
The ratio of its maximum value to the RMS value.
What is the relationship between the RMS value and the average value of a sinusoidal quantity?
The RMS value is 1.11 times the average value.
What is the condition for inducing an emf in a conductor?
When a conductor cuts across a magnetic field or when there is a change in magnetic flux.
Learn about electromagnetic induction, dynamically induced EMF, and its applications in DC generators, induction motors, and alternators.
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