Electrical Engineering

because the hermatic compressor motor must be compatible with the refrigerant and oil circulating in the system.

multiplying factor = Line CT Ratio / Meter CT Ratio

Usually it is mentioned on Meter that MF = 1 if CT Ratio is 200/5 or MF = 2 if CT Ratio is 400/5. There can be an additional multiplication factor that would be mentioned on the meter.

'http://wiki.answers.com/Q/If_breaker_CT_ratio_8001_when_current_of_any_phase_crossed_800_ampere_what_would_happen'

Ring Main Unit (RMU) is suppose to work in medium voltage. It is flexible and allows a free flow and maintains continuity. These are very compact in size. RMU are both Extensible & Non-extensible types.

An in line device used in filtering ac votlage out of transient or (electrical noise) before allowing the electrical current to enter an electronic board of certain designs.

The fan will have a pair of short wires that come out of the fan motor connected to another short pair of wires going back to the fan's motor. The 2 pairs will be connected to each other with either a single 2-prong connector or two single-prong connectors. Reverse the connection pairings and the fan will spin the opposite direction. (If you have a 2-prong connector, just unplug the connector; twist one end of the connector 180-degrees; then reconnect.)

It is the housing standard on a motor

Totally Enclosed Fan Cooled

When the output voltage is higher than the input voltage that is considered a step up transformer. When the output is less than the input you have a step down transformer. Input is also called primary and output secondary.

Explain the workin principle of uln and its abbreviation

short all the high voltage bushings toghether.do same with low voltage bushings.disconnect the neutral from the ground.earth the body of the transformer.earth the ttr set.

connect the common point of high voltage bushing to hv terminal of ttr and connect the common point of lv bushing to lv terminal of ttr set.connect the neutral of transformet with the n terminal of ttr set.

now crank the generator.im out of time will answer this question later

When rotor bars are made to run parallel with stator , the

torque rises & falls correspondingly causing more

pulsations. This is termed as cogging in other qords

magnatic locking. This is reduced by making the rotor bars

run at an angle to the stator ie crawling in order to make

the torque uniform.

Crawling on the other hand signifies running of motor at

almost one seventh of the rated speed due to interference

of seventh harmonics.

A square wave will have the highest value since it has a peak, positive or negative, all of the time. Other wave shapes such as triangular and sine, have a lower value than this.

Coax is normally used in high frequency applications due to its ability to shield the signal. The coax construction prevents radiation, while at the same time prevents noise pick up. It is the shielding that makes coax a better choice at higher frequency, however coax can be used as low as audio frequencies.

Lower frequency systems do not need the shielding due to the long rise times. They are not as sensitive to noise pick up and generally do not radiate.

160 Amp. MCCB 45 KW Contactor (67.5-112.5) Thermal Over Load

The transition from star connection to delta connection requires that the current flow through the motor is interrupted. This is termed "Open Transition Switching" and with an induction motor operating at partial speed (or full load speed), there is a large current and torque transient produced at the point of reconnection. This transient is far worse than any produced by the DOL starter and can cause severe damage to equipment and the supply.

A Shockley diode is a primitive diode identical to a thyristor with it's gate left disconnected.

A Schottky diode is similar to a normal avalanche diode except that it's forward voltage is quite low, and it's switching speed is very high.

Current limiting is the practice in electrical or electronic circuits of imposing an upper limit on the current. The simplest form of current limiting in mains is fuse.

In vacuum tube devices, one electrode of the tube (the filament) needs low

voltage at relatively high current, while another one (the plate) needs a high

voltage at relatively low current. It's hard to build a single power supply to

provide both of these, so the filament is usually supplied from its own

separate transformer.

Nobody has worried about things like this since a short time after transistors

came along.

desai

I'm not an electronic whiz by ANY means, but if I'm correct...Transmitters do the sending and antennas do the receiving.

They refer to the number of I/O lines (not power) needed to transfer data between to processors/controllers.

3 wire serial has a bidirectional data line, a clock line, and a master/slave line.


2 wire generally is clock and data.

Potential Difference (p.d) in an electric circuit is the measurement of energy transfer per unit charge in volts (v) or joules per coulomb (JC^-1). However, in contrast to the Electromotive Force (emf) in a circuit, which is a component that adds charge to the current (usually a cell). p.d uses up the charge to power a component eg a lamp. We would express this as the potential difference across the lamp. We can also say pd (v) = workdone (W)/ charge (Q). because the transfer of energy is the work done and this is per unit of charge.

Example.

What is the pd through a lamp where we have 4 coulombs of charge passing through it and transferring 48 joules of electrical energy into heat and light.

V=W/Q

pd=48/4 =12v

A device, composed of sharp points and/or knife edges, that discharges powerline overvoltages to ground. The term lightning arrestor is a misnomer, as these devices cannot protect against a direct strike to the powerline!