ALL TIME ELECTRICAL

Capicitor Application Issues

Capacitors must be built to tolerate voltages and currents in excess of their ratings according to standards. The applicable standard for power capacitors is IEEE Std 18-2002, IEEE Standard for Shunt Power Capacitors.

Testing and commisisioning procedure for motors

Heat as one of most common cause of motor failure

This slide speaks about that how motor operation fails due to heat. how heat affect motors?

A Practical Gauide to earth resistance testing

Best practical Manual for Transformers

Monday, 12 May 2014

What are the advantages of star-delta starter with induction motor?

06:54 No comments

The main advantage of using the star delta starter is reduction of current during the starting of the motor. Starting current is reduced to 3-4 times Of current of Direct online starting.(2). Hence the starting current is reduced; the voltage drops during the starting of motor in systems are reduced.

Why is the starting current high in a DC motor?

06:52 No comments

In DC motors, Voltage equation is V=Eb-IaRa (V = Terminal voltage,Eb= Back emf in Motor,Ia = Armature current,Ra = Armature resistance).At starting,Eb is zero. Therefore, V=IaRa, Ia = V/Ra , where Ra is very less like 0.01ohm.i.e,Ia will become enormously increased

What is meant by regenerative braking?

06:51 No comments

When the supply is cut off for a running motor, it still continue runningdue to inertia. In order to stop it quickly we place a load (resistor) across thearmature winding and the motor should have maintained continuous field supply.so that back e.m.f voltage is made to apply across the resistor and due to loadthe motor stops quickly. This type of breaking is called as "RegenerativeBreaking