Electrical Engineering

By simulating a earth leak on the device connected to ELCB. A short between phase and the body or earth point. Care must be taken. It must be done by a trained Electrician only. It is dangerous to do it.

For an ideal transformer, the voltage ratio is exactly the same as its turns ratio. So if, for example, there are twice as many turns on the secondary winding as there are on the primary winding, then the secondary voltage will be twice that of the primary and the transformer will be a 'step up' type.

A major cause of decomposition of transformer oil is minor arcing within the transformer. Decomposition results in gas which bubbles towards the top of the transformer and upward into the conservatory tank. Between the transformer and conservator tank is a Buchholz relay, in which this gas collects, causing a mercury switch inside a float to initiate an alarm in the substation. This gas can be collected through a small pipe feeding from the Buchholz relay in order to have it analysed.

Yes, only relative motion between the coil and the magnetic field is important.

I have designed many charging circuits and generally we try to keep the max recharging rate of around 10% of the battery's discharge rating. For your Nickel-Metal-Hydride (Ni-Mh) battery that would be a maximum of 80 to 100 Ma.

Your gun was manufactured in 1941.

If its a rifle:

Exc V.G. Good Fair Poor

$3000 2000 750 500 200 If its a saddle ring carbine

3000 2000 600 400 200 If no saddle ring, deduct 35%

To reverse the direction of the current, and keep the thing ( rotor, armature) going in one direction. The older term, applied to some automobile use, was timer. The French correctly refer to the Balance Wheel of a watch as a commutator, using the French spelling of commutateur. Some expensive watches had solid Gold commuator screws on the balance wheel!

did u find out yet

The running time depends on two things: the actual power the inverter can supply, and the actual power drain of the loads.

A 1000 VA inverter may be able to supply 1000 VA, but it battery size determines *how long* it can supply power for. A 100 amp battery can probably supply 10 amps for 10 hours (100 amp-hours), but it may only supply 100 amps for perhaps 45 minutes - if it does not overheat! Generally, batteries give less effective power at higher power drain.

You also need to know how efficient your inverter is - it may be 90%-plus, it may be as bad as 75% or less.

So you will need to (1) find out how much power your appliances draw (let's say its 300 watts), then (2) examine the specifications for the inverter-battery combination to discover how long they can support your power drain.

Be aware that 300 watts load is over 25 amps current drain at 12 volts, so you are already getting away from the 100 amp rating, to a lower value due to the high power drain on the battery.

Diversity factor is the ratio between sum of each individual maximum demand and the total maximum demand.

There are several equipment with different connected load and its maximum demand in an industry. Each equipment maximum demand could be different and might occur at different times. A well estimated or measured diversity factor would tell as to what percentage of total maximum load would actually occur. Diversity factor is always less than 1.

Diversity factor has to be obtained either by measuring the actual sum of each individual load and maximum demand or estimated and has relation to the transformer full load .

Power companies in the west purchased 60Hz equipment, and companies in the east purchased 50Hz equipment. This was back in the late 1800's to early 1900's. It would be cost prohibitive to replace all the 50Hz equipment with 60Hz, or vice versa at this point, so both are used.

Corona.

--guarantees serializability

--The protocol utilizes locks that block other transactions from accessing the

same data during a transaction's life.

by

Raja Done M.Tech

There really is no standard color for this. Most that I have seen use the Black as the positive (+) and the white as negative (-) but I have also seen it the other way around. Just follow the convention of the plant or customer where you are working.

Once derating factor is considered the size of cable for perticular electrical load increased by the multipling factor.i,e if 2.5MM2 cable is capable to carry 14amp. of current in general then with 40% of derating fator it can carry only 8.4amp.

Physical properties means the behavior of materials in response to physical forces other than mechanical, such as; Volumetric, thermal, electric and electrochemical properties. Most Ceramics are lighter than metals but heavier than polymers.

Most ceramics have a higher melting point than most metals as it is that some ceramics such as China can with stand high temperatures to about 1200 degrees centigrade. Ceramics also has lower Electrical and Thermal Conductivity than most metals but the range of value is greater in ceramics permitting some ceramics to be used as insulators, for example Porcelain insulators and others as conductors like Lithium-ion conducting glass-ceramics and oxide ceramics.

Thermal expansion is another physical property of ceramics, Ceramic thermal expansion coefficients are less than those of metals but effects are more damaging in ceramics bringing about cracks and other failures(Thermal shock and thermal cracking) as for ceramic materials with relatively high thermal expansion and low thermal conductivity however there is glass ceramics that has low thermal expansion thus resisting thermal shock and thermal cracking, for example Pyrex glass ceramics. Thus the physical properties being but not limited to permeability, elasticity, considerable strength, hardness, brittleness, resistance to chemical attack and thermal shock.

Ohm's law states that the current in a circuit is inversely proportional to the circuit resistance. There is a single path for current in a series circuit. The amount of current is determined by the total resistance of the circuit and the applied voltage.

In OC test , the equipments are connected in LV side since we need to get rated voltage . if it is cinnected in HV side the value of voltage will be less and current wil be more.Hence the ordinary instruments cannot measure this value of current

Biogeochemical cycles are basically of two types:

a) Gaseous cycles like carbon (as carbon dioxide), oxygen, nitrogen, etc.

b) Sedimentary cycles like sulphur, phosphorus, etc.

In gaseous cycles, the elements have a main reservoir in the gaseous phase, and the reservoir pool is the atmosphere or water. The biogenetic materials involved in circulation pass through a gaseous phase before completing the cycle.

In sedimentary cycles, the elements main reservoir pool is lithosphere and the biogenetic materials involved in circulation are non-gaseous. The sedimentary cycles are usually very slow as the elements may get locked up in rocks and go out of circulation for long periods.

If the switch, light bulb, and source are all connected in series and the switch is ideal (has no resistance), then the switch acts as a short. There is no potential difference across the short.

This terminology usually refers to pad mounted transformers. A "radial feed " transformer is a transformer that has one bushing for the high voltage cable line. The high voltage cable terminates into the transformer through the transformer's bushing. There is no second bushing for the high voltage cable to continue further down the line. This type of transformer is usually on the end of a loop feed circuit.

This is different from a "loop feed" transformer whose incoming cables are terminated at the primary bushings. On this type of transformer there is a second bushing which connects to the outgoing primary voltage cables that allows the primary to feed another transformer. Each pad mount transformer's secondary feed usually supplies enough power to connect up to four homes.

A traditional technology which is used for ploughing the filed is known as plough.The working principle of plough is pulling and digging.

//you tell us and we'll both know

assuming that you have used h-parameter analysis for this ...Vb contains the Ib and the Ie terms which can be expressed ad Ie=(1+Hfe)Ib

then we have

Vb=Hie*Ib + Re*Ie
=Hie*Ib + Re(1+Hfe)Ib
=Ib(Hie+(1+Hfe) Re)

then we can find
Ri as Vb/Ib= Hie+(1+Hfe)*Re

hope that helps....

A single phase 10 HP motor will draw aproximately 50 amps. A three phase 10 HP motor will draw aproximately 28 amps.