Electrical Engineering

It depends on your definition of efficiency. 480 can certainly push more power than 208 through the same size conductors, but it would not be efficient to wire a motor for 480 when 208 was all that was needed.

Polyphase is a general term that includes all electric power systems using three or more phases.

It will be often desirable to know the power which is being consumed in operating a lathe on certain work for which data is required. For most purposes this can be sufficiently approximated by calculating the power of the lathe from the width of the belt and its speed in feet per minute.

For such purposes it is usual among mechanical engineers to consider that a one-inch belt traveling a thousand feet per minute will transmit one horse-power. This will give us a key to the entire calculation.

1 ton is about 1 hp or 1 kw

so about 20

caveat:

cant start more than 5 at once

if they are sufficient size to cool their respective spaces

as they reach desired temperature more can be started

should be fine to maintain temperature

220 volt is single phase, so power is the straightforward IxE calculation.

30V X 220A = 6600W = 6.6KW

Martin Cooper invented the cell phone because it was his vision of personal communication, as opposed to mobile phones in automobiles. His inspiration was the communicator on the Star Trek TV series.

0.2S is more accurate at low currents than 0.2. While both have maximum errors of +/- 0.2% at 100% and 120% of rted current, 0.2S has +/- 0.75% at 1%, 0.35% at 5% and 0.2% at 20 % of rated current while 0.2 has 0.75% at 5% and 0.35% at 20% rated current. These values are found in IEC Standard 60044, Tables 11 and 12.

Schottky diodes are often used for RF radio frequency applications as a mixer or detector diode.

Another common application for the Schottky diode is in power applications as a rectifier.

Split-phase motors are used in many applications that require a medium amount of performance from a single phase source. Many of the motors used in homes that are supplied by single phase power are split-phase motors.

Some applications include running fans, blowers, water pumps, air compressors, conveyor belts, and more. The only limits on the applications that can use split-phase motors are the availability of single phase power and the charectoristics of the motor itself.

Armature is a rotating part of the machine, the coil which wound in the core of that rotating part.

A full wave bridge rectifier converts AC (Alternating Current) into DC (Direct Current) with an AC component. To achieve DC only, the output of the bridge rectifier must have the AC component removed by bypassing it, usually with capacitors.

It consists of 4 diodes in a bridge format. During one half of an AC cycle, two of the diodes conduct and on the other half a cycle the other two conduct. Diodes allow current to flow in one direction only.

A diagram can be found at http://www.allaboutcircuits.com/vol_6/chpt_5/5.html

Bypass capacitors are used to bypass (shunt) unwanted signals to the ground. A common use is in power supplies where a bypass capacitor is connected in parallel with the main filter capacitor to shunt noise and other high frequency interference to ground which the main capacitor may not be able to do.

To measure current you will need an ammeter.

The three phase voltage is 380 the hertz is 50

Approximately 746 watts of usuable power are equivalent to 1 horsepower. A 1hp motor, under full load, will draw more than 746 watts due to the inherent losses in the motor itself.

The neutral current in a three-phase, four-wire, a.c. unbalanced load is the phasor-sum (vector-sum) of the three phase currents. That's more-easily said than done, as the maths can be quite difficult -certainly too difficult to explain in WikiAnswers, so you should refer to a textbook which covers the topic. Probably the best approach is to use the 'a-operator', the equivalent of the 'j-operator' used for single-phase loads.

It depends on the refrigerator. Mostly the average is about 240~280v

So i wouldn't touch it if I were you!

Your two hot wires go to the load side of your contractor and the two brown wires go to your capacitor

That depends both on the light bulb's power rating, and how long you want to light it! Use the formula:

energy = power x time

If the power is in watts and the time in seconds, then the energy will be in joules (= watt-seconds).

Alternately, if the power is given in watts, you can divide by 1000 to convert to kilowatts. Then, if you multiply by hours, you get kilowatt-hours. Note that the unit used by utility companies tp charge you is kilowatt-hours.

it depend how you look at they came up with several similar thing that were not quit maglev train starting for the 1900's but the actual model started in 2001 and finish in 2005 so it about 4 years

If resistance is halved while voltage remains constant, the current will double.

Capacitor banks can improve the power factor if the load is leading, which is unusual. Typically in substations capacitor banks are employed to reduce over voltage.