Electrical Engineering

There is no such thing as phase in DC as phase requires AC.

To have two or more things out of phase requires them to be changing. Only AC does that. DC is steady state.

The net measured power would appear to be negative, or reversed.

Basically at noloads the current value is less so we use lpf at no loads

A CT is a measuring device but does not step up or step down voltage like a transformer will.

My understanding is that on most (if not all) differential relays, there are currents coming in from both sides of the operating coil. These currents should cancel out, or in reality, nearly cancel out. Therefore, the effective current in the operating coil is zero. When the net current in the operating coil is not zero, the relay trips.

There are instances when you don't want the relay to trip though. Therefore, the operating coil works together with a restraint coil. (Well probably 2 restraint coils.) The relay will trip if the operating coil's current must exceed the restraint coil's current by a certain amount.

i adjusted tappet on cat engines by turning the engine first

piston no.1 in TDC and check all (intake/exhaust) valves in close position,or follow maintenance guide book ,then check again when piston no.1 on exhaust stroke the same procedure be taken. or do it by turning the engine till the individual piston on TDC as perengine firing order and adjust both valves

In dual combustion cycle heat is added at constant volume which increases the efficiency of cycle, whereas heat addition at constant pressure limits the maximum pressure of the cycle.

Magnetic balance test is performed on transformer to check, whether the core and windings of the transformer is balance position or not.

Magnetic Balance is a test of Critical use as it helps us to enhance the efficiency and life of transformers.

No. A CVT (capacitor voltage transformer), like an voltage transformer, has a high primary impedance. the connections of a CT require the high voltage current to pass through the primary winding. This would result in significant loading of the circuit in question, at least until the CVT cooked.

It probably doesn't matter. But a "disconnecting means", as the NEC calls it, is not intended to be operated while under load, which is when the equipment is running. It is intended to isolate the equipment so it can be serviced safely. A breaker by its very nature is intended to be operated under load.

The larger the equipment, the more this matters.

Usually star connections are needed in places where lots of peripheral connectors have to be made. these types of circuits are most common in domestic power connections in highly crowded and power demanding sectors.

Thanks.

Conductance is ignored in short circuit studies because the inductance of the line is the dominant value. Conductance may not be ignored in stability studies.

It depends on how the diode is damaged. There are generally two cases. One, the diode is shorted, and conducts with a low impedance in both directions. The other, the diode is open, and does not conduct, having a high impedance, in both directions. The effect depends on the particular circuit. In a power supply, a shorted diode will often blow the fuse, while an open diode will result in no output, or in high ripple voltage output.

Is it possible that diode has normal voltage output but wrong current,meaning low mA?

This is too complicated to describe on this forum, but there are lots of web pages that describe the 'three-ammeter' method of measuring power, so your best plan is to visit one of those sites.

I'd have to see a diagram, as your description in words is unclear.

If the refrigerant is not at an optimal level (either too low or too high), the system will have to work harder to produce the same amount of cooling. This results in more electricity being used to get the same amount of cooling.

To limit the fault current used surge protective resistance in generator rotor winding to protect the rotor winding heavy damage.

It is what you do after you finish the windig.

Residual voltage is the vector sum of all three phase voltages. Ideally this will be zero.

contactor are usually bulkier than relays .they are usually used for supplying power to heavy current using equipment eg industrial motors etc.relays are generally used in control panels supplying power to less current using control equipment

In theory, you can. If you have a power transformer rated at 480 primary side and the secondary at say 120VAC, then the ratio is 4:1. Meaning that there are four times the number of turns on the primary side as to the secondary. So, if you were to power the primary side with 120VAC as opposed to 480VAC you would expect to see a 1/4 reduction in voltage output on the secondary, or 30VAC. The current would be dependant on the cross section of the secondary conductor and core construction. As current is increased thru the load (as in resistance welding) for example, you would expect voltage to decrease or lag, a larger Industrial sized transformer is able to compensate for this lag in voltage better than a compact household power transformer.

If you want 100kVAR from a capacitor bank, you must install a 100kVAR capacitor bank. If what you're asking is related to how much capacitance it will take to offset a poor power factor, it is directly related to your load, and cannot be answered without more details - for power factor correction, you don't want to over correct (you would be buying too much equipment, and it could actually make your power factor look worse), so load profiles must be taken into account. Can the capacitors be switched on automatically, or must they be manually switched? What voltage level? The best way to determine this is to discuss with your local power company. They usually have people on staff that analyze this sort of thing on a regular basis, and if they don't, they could at least point you in the right direction.

a transistor circuit for driving the coil of a magnetic relay.