Electrical job question: What is Power Factor ?

Types of Current: There are two types of currents present in the AC circuits. The current required by induction motors, transformers, fluorescent lights, induction heating furnaces, resistance welders, etc., may be considered to be made up of two separate kinds of current:...

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Methods to avoid low Power Factor

Some of the methods to improve power factor are: 1.     Induction motors have maximum power factor when they are fully loaded and power factor starts falling down when the motor loading is reduced and becomes worst during no load. Hence, it is important not to have motors too big for a specified job than  its...

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Causes of Low Power Factor ?

Some of the reasons for low power factor are: Induction motors and Transformers: Where ever the magnetising current is to be produced by the ac power such as in the cases of transformers, induction motors and reactors the power factor will be significantly low. The current drawn by these machines or equipment will always lags behind the voltage....

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Why Instrument Transformers Used and Advantages

Voltmeters and Ammeters are used to measure the voltage and current in the circuits. Using instrument transformers ranges of these devices to measure can be increased. A current transformer is bascially a step down transformer hence it steps down the current. When used in conjunction with the low range ammeter, a current transformer (CT)...

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Moving Coil (MC) Instruments Advantages Disadvantages

The operation of moving coil meters depends on the electromagnetic effect of the current ( a force is excerted on the current carrying conductor when placed in a magentic field ) Moving coil instruments are of two types: Permanent magnet type Dynamometer ...

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Difference between Current Transformer (CT) and Potential Transformer (PT)

Current Transformers (CT) and Potential Transformers (PT) are used to measure the current and voltage in a circuit of the order of hundreds of amperes and volts respectively.  A CT has large number of turns on its secondary winding, but very few turns on its primary...

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Indian Engineering Services (IES) Objective Questions and Answers:Machines1

Indian Engineering Services Objective Questions and Answers 1) Match the Following   ( IES- 2003)       List I                                        List II  A. Transformer                           1. Slip Test B. DC Motor                               2. Blocked Rotor...

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Indian Engineering Services (IES) Objective Questions and Answers:Machines

1) A self excited d.c shunt generator, driven by its prime mover at the rated speed fails to build up the voltage across its terminals at no load. What reason can be assigned for this? (IES 2006) a) The initial shunt field mmf does not assist the residual magnetism b) The field circuit resistance is higher than the critical resistance c) One...

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TRAIN LIGHTNING SHOP

The shop deals with the periodical over haul of the fans, batteries and the rotary switches used in the train. The basic details of the equipments over hauled in this shop are as follows: Fans:                 ...

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POWRE HOUSE

Power is supplied to the entire workshop with the help of two feeders north and south. If any fault occurs in any one of the two feeders, then total supply is given by the other feeders. The feeders take supply from HYDEL comes into HT panels of the power house. In the HT panel there are OCB’s and MCCB’s which trip down to off position in case of...

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