Related Questions

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

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