EE8301 Important Questions Electrical Machines 1
EE8301 Important Questions Electrical Machines 1 Regulation 2017 Anna University free download. Electrical Machines 1 Important Questions EE8301 pdf free download.
Sample EE8301 Important Questions Electrical Machines 1:
1. Mention the types of electrical machines.
There are three basic rotating machines types, namely
a. The dc machines
b. the poly phase synchronous machine (ac), and
c. Poly and single phase induction machine (ac)and a stationary machine,
namely Transformer EE8301 Important Questions Electrical Machines 1
2. State Ohm’s law for magnetic circuit.
It states that the magneto motive force across the magnetic element is equal to
the product of the magnetic flux through the magnetic element and the reluctance of
the magnetic material. It is given by
MMF = Flux X Reluctance
3. Define leakage flux
The flux setup in the air paths around the magnetic material is known as
4. Define magnetic reluctance EE8301 Important Questions Electrical Machines 1
The opposition offered by the magnetic circuit for the magnetic flux path is
known as magnetic reluctance. It is analogous to electric resistance.
5. Draw the typical normal magnetization curve of ferromagnetic material.
6. What is fringing?
In the air gap the magnetic flux fringes out into neighboring air paths due to the
reluctance of air gap which causes a non uniform flux density in the air gap of a
machine. This effect is called fringing effect.
7. State stacking factor. EE8301 Important Questions Electrical Machines 1
The stacking factor is defined as the ratio of the net cross sectional area of a
magnetic core to the gross cross sectional area of the magnetic core. Due to lamination
net cross sectional are will be always less than gross cross sectional area. Therefore the
value of stacking factor is always less than unity.
8.Mention some magnetic materials
Alnicos, chromium steels, copper–nickel alloy, nickel, cobalt, tungsten and aluminium.
9. What is magnetostriction?
When ferromagnetic materials are subjected to magnetizing mmf, these may
undergo small changes in dimension; this phenomenon is known as magnetostriction.
10.Define statically induced emf.
The coil remains stationary with respect to flux, but the flux through it changes
with time. The emf induced is known as statically induced emf.
11. Define dynamically induced emf. EE8301 Important Questions Electrical Machines 1
Flux density distribution remains constant and stationary but the coil move relative
to it.The emf induced is known as dynamically induced emf.
|Subject name||Electrical Machines 1|
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