Answer / b sumanth kumar

Due to the property of residual magnetism.According to
residual magnetism property when motor is turned off then
the magnetism property of the poles do not lost some what
of the magnetic property will be present by this motor can
produce its back emf at the time of starting

HOW to speed control of induction mototr using scalar control

3 Answers  

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SMPS (Switch Mode Power Supply) unit is denoted by KW or KVA?

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Energy metering: On the property I am renting, the supply voltage is 2 x 110 volts. These 2 x phases enter a energy meter which then exit the meter to over head lines to my house. Question 1. The meter is single phase 240 volts but is being used as 2 x phase(2 x 110volt), is this acceptable? if not, please give me the reasons. The meter details are as follows: 60Hz 15amp Imax 100 amp Kd 3,6 Wh/R 1 fase 3 hilos Model FX 231. I think it was manufactured in Brasil From this meter, the cables run along over head aluminum conductors,I estimate the cross sectional area to be 25mm diameter, but the neutral is only about 10mm square diameter, which cover a distance of 170 meters and then terminate with an underground cable of 65 meter length, total length = 235 meters. There must be a huge voltage drop over this length. This line is protected with 2 x 200 amp aluminum fuses after the meter, there is no main switch in the distribution board. These 2 phases connect directly onto 2 busbars. Surely the neutral should be the same size as the conductors if not more? Question2. What are your thoughts about this installation, should there be better protection, is the neutral too small? During the night, the lights dim then brighten all the time, this cannot be good for my electrical appliances. In my home, I only have a small electric geyser and fridge, my stove works off gas. But when i use other appliances like the washing machine or microwave oven, the light dim. The internal wiring of this house is done with solid hard drawn copper wires and of course, they have to be under rated. I am a retired electrician by trade, but not on the metering and over head mains side, my experience is on the factory maintenance side of things. Your expertise on these matters will be greatly appreciated. Please inform me how to rectify or make any improvements Kind regards, my power bill is very expensive, so I need to know how to bring it lower. Kind regards, Brian

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Is it possible to use a S1 duty class motor for crane application (S4)? If not, why?

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What is the deference between earth fault & earth leakage

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I have running 4 generator in paralel.All generators Voltages is same(470 V),KW also same (100 KW) but only No2 generator Amper is high than another generators. DG No:1,3,4 470V,100KW, 150 A DG No:2 470V,100KW,400 A

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In the case of petrochemical area AC drive & AC motor is used where the speed variation is required. Why they are not Using DC drive & DC motors in such areas?

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why lightining is not available in swith yards?

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power transmission pole used one support , that only for support or earthing

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How to minimize the eddy current losses?

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Give the two basic speed control of DC shunt motor.

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what is the difference between electrical degree n mechanical degree?

3 Answers   IGCAR,

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