What is the full form of PILC, PILCSTA and PILCDTA Cables?

• PILC - Paper Insulated Lead covered Cable
• PILCSTA - Paper Insulated Lead covered Single Taped Armoured cable
• PILCDTA - Paper Insulated Lead covered Double Taped Armoured cable

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What is Starter and what are the main functions of starter?

Starter: The device used for starting the D.C. motor.

Main functions:

1. To protect the motor from taking overload current.
2. To protect the motor against supply failure.
3.  To faccilitate the starting and stoping of the motor.

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Why a generator is overheated?

It can be because of:

1. Sparking on the commutator.
2. Defactive bearings.
3. Short circuit in field or armeture.

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Why a generator fails to build up the voltage?

It can be because of these reasons:

1. Loss of residual magnetism.
2. Reverse d.o.r.
3. Condition of load (more and more load).
4. Brushes not in m.n.p. position.
5. Open circuit in field or armeture circuit

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How you can improve the commutation?

1. By using compenseting winding or interpoles.
2. By using high resistance brushes.
3. By giving a slide forward lead to the brushes.

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What are the effects of commutation?

1. Sparking at commutator.
2. Life of commutator reduces because of sparking.
3. Less output of the generator.
4. MOre temperature raise in armeture winding.

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What is the reason of sparking on the commutator?

The main reason of sparking is the failure of the current to reach its full value in opposite direction, in the coil undergoing commutation.

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How is the most suitable motor selected?

Selection of a motor for a specific application: 

   •   Starting as well as running characteristics (operating voltages and currents)
  •   Life span
  •   Possible speed control and maximum operating speed
  •   Size and weight considerations
  •   Level of noise present in the operating environment
  •   Suitability of the motor for constant, intermittent, and frequently variable loads
  •   Capacity in case of overloads and torque characteristics
  •   Available power supply
  •   Installation as well as running cost
  •   Frictional characteristics  

 To explain these points more clearly, consider an application-based problem and design

modifications that can be applied in induction motors to make them suitable for different torque

requirements and therefore different applications. 

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Where motors are used?

An electric motor is an electromechanical device that converts electrical energy to

mechanical energy. This mechanical energy is used for, for example, rotating a pump

impeller, fan or blower, driving a compressor, lifting materials etc. Electric motors are used at

home (mixer, drill, fan) and in industry. Electric motors are sometimes called the “work

horses” of industry because it is estimated that motors use about 70% of the total electrical

load in industry.

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What are data communication systems?

Data communication systems: A set of devices (hosts) connected by a communication medium that are able to share data through transmission over the media

•It is a combination of hardware and software that allows data communication to occur

•The effectiveness of data communication depends on four fundamental characteristic.

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