Electrical Engineering

A thyristor, also known as a silicon controlled rectifier, is a diode that can be turned on by application of a small gate voltage.

A transformer has two coils wound over a core. Depending on use, the two coils are named primary and secondary coils. The primary and secondary coils are linked magnetically (not electrically except in case of auto transformers) called mutual coupling. When the primary coil is excited with alternating voltage(A.C), varying magnetic flux is produced which links with the secondary coil and thus a voltage is induced in the secondary coil. Since there is no rotating or moving part utilized for the above process hence transformer is called a static device.

The word static used here should not be confused for static charges. It only signifies "not moving"

Mesh current is introduced just as an imaginary quantity it flows around a mesh and all branch currents do not change for introducing mesh currents so all branch currents can be represented by mesh currents.

Busbars are not necessarily rectangular. Those used in substation compounds are frequently tubular in construction.

10 ma times 50 ohms is 0.5 volts. 0.5 volts is one two hundreth of 100 volts, so the multiplier resistor on 200 time 50, or 10,000 ohms.

A symmetrical fault is a fault where all three phases are experiencing the same thing. This is also called a three phase fault, since all three phases are involved.

altinator

OCTC means off circuit tap changer (off load tap changer) and OLTC means on load tap changer. in octc we can change the tap position while the transformer is in off condition only. we can not change the tap position of octc in charged condtion of the transformer. the tap position of octc can be change in deenrgise condion of transformer only means if you nwant to chang the tap position firstly you will have to deenrgise the power transformer then you can change the tap position of octc.while in oltc we can change the tap position of OLTC in charged condition of power transformer. This is the basic diffirence between OCTC and OLTC.generally the OCTC used in single phase generating transformer (G.T.Power Transformer) and OLTC used in three phase powwer transformers like standby transformer and auto transformer in power plants and switch yards. for any other question please mail me at (ashu_uit2007@yahoo.co.in )

This is the rated output of the transformer, obtained by multiplying the rated secondary voltage by the rated secondary current. And it's 'kV.A', not 'kva'.

no

An 'oscillating' neutral can exist when the star point of a three-phase, star (wye) connected, secondary winding becomes disconnected from earth (ground) -e.g. if copper thieves have removed the earth conductor or it simply becomes disconnected. This results in a 'floating neutral', in which the phase voltages are no longer necessarily equal to each other (in other words, the three phase voltages have become 'unbalanced') the extent to which depends upon how unbalanced the supplied load is. An 'oscillating' neutral occurs when the displacement of the neutral point changes as it responds to changes in the unbalanced load currents.

There is no inherent disadvantage of 50 Hz compared with 60 Hz, bearing in mind that systems that run at 50 Hz are designed to run at 50 Hz.

make sure theres a load connected in a series. thats all i remember

When low inductive currents, such as magnetiing current of transformer, shunt reactors are interrupted by breaker, there is rapid deionization of contact space and may cause the current to be interrupted before its neutral zero. This phenomena is callad current chopping

The term, 'star point', refers to the common point of connection for the three windings of a star-connected (wye-connected) transformer connection. The star point is usually earthed (grounded) and provides the neutral point of the connection.

A big one.

A 'current transformer' (CT) is classified as an instrument transformer, which means it is used to provide a small secondary current that is in proportion to its large primary current, for purposes of metering or protection. At the same time, it electrically-isolates the secondary (metering) circuits from the primary circuits (which are often high-voltage circuits) for the purpose of safety.

no 208v is bigger

an ideal ammeter has zero or negligible resistance when this is connected in series no effective resistance would be added in the circuit so that the value of curret that we get is exactly of the circuit only. but when the ammeter is connected in parllel as it has zero resistance , the resistor to which it is connected in parllel gets shorted and due to his the effective resistance of the circuit is changed and so the effective current ... due to this the w=value measured by the ammeter would be different (incresed due to dec. in effective resistance)

300a

It is very critical to never exceed the input voltage of an IC to begin with. To calculate the power dissipation ( in watts) VxI (Voltage x Current) will give you power in watts.

It's bimetal so opens when warm releasing choke which richens mixture until warm enough to run without it.

FS= critical hydraulic gradient/exist hydraulic gradient

icr=(saturated unit wt - water unit wt)/water unit wt

a magnetic field

Yes, a step-up transformer has fewer turns of wire in the primary than in the secondary.