________ is the common method of applying brushes to the commntator.

If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be

A

Demagnetization only

B

Cross magnetization as well as magnetization

C

Cross-magnetization as well as demagnetizing

D

Cross magnetization only

Applying for Seasonal Employment occurs when a person requests to be considered for a job that is dependent on a particular season or time of year. Which situation below is the best example of Applying for Seasonal Employment?

A

The ski instructors at Top of the Peak Ski School work from December through March.

B

Matthew prefers jobs that allow him to work outdoors.

C

Lucinda makes an appointment with the beach resort restaurant manager to interview for the summer waitressing position that was advertised in the newspaper.

D

Doug's ice cream shop stays open until 11 p.m. during the summer months.

In ________ the speed can be varied by changing the position of brushes.

A

Slip ring motor

B

Schrage motor

C

Induction motor

D

Repulsion motor

Electrical contact materials used in switches, brushes, relay must possess

A

High thermal conductivity and high melting point

B

Low thermal conductivity and low melting pointL

C

High thermal conductivity and low melting point

D

Low thermal conductivity and high melting point

_______ brushes are fragile and cause excessive wear of commutator,

A

Natural graphite

B

Hard carbon

C

Electro graphitic

D

Metal graphite

The rapid wear of brushes takes place due to

A

Abrasion from dust

B

Excessive spring pressure

C

Rough commutator bars

D

All of the above factors

To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so as to bring them

A

Just ahead of magnetic neutral axis

B

In magnetic neutral axis

C

Just behind the magnetic neutral axis

D

None of the above

Copper brushes in D.C. machine are used

A

Where low voltage and high currents are involved

B

Where high voltage and small currents are involved

C

In both of the above cases

D

In none of the above cases

The material for commutator brushes is generally

A

Mica

B

Copper

C

Cast iron

D

Carbon

Armature coil is short circuited by brushes when it lies

A

Along neutral axis

B

Along field axis

C

In any of the above positions

D

In none of the above positions

________ is the common method of applying brushes to the commntator.

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