Electrical Engineering
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Electrical Wiring

Why is 1 phase 240 volts and 3 phase 415 volts?

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Answered 2015-02-21 09:13:20

In a three-phase, star- (or wye-) connected, system the line voltage (line-to-line voltage) is 1.732 (or the square-root of 3) times the phase voltage (line-to-neutral voltage). The reason for this is that a line voltage is the vectorial sum (not algebraic sum) of two phase voltages displaced from each other at 60 degrees.

These days, incidentally, the UK's nominal phase voltage is 230 V, and its corresponding line voltage is 400 V.

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Can you turn a 3 phase into a 220?

Yes, 3 Phase, 415 Volts can be converted into 1 Ph, 240 Volts. Voltage between one of the phase (among 3 phase) and the Neutral is 239.6 Volts. How?: 415 V / root(3) = 239.6 Volts

How many amps does a 1000 watt bulb draw at 220 volts 1 phase?

220 volts is not 1 phase, its 3 phase. In North America 220 - 240 volts is single phase. Divide watts by volts to get amps, ohms law

On trace heating 415 Volts if you lose a phase on a 3 phase system what percent of heating have you losed?

1/3 rd lost

What is the current drawn in each phase of 15 HP 3 phase 415 VAC motor?

1 HP=746 watts 15 HP=11,190 watts Ohm's Law says Current (in Amps) = Power (in Watts) divided by Voltage (in Volts) 11,190 watts divided by 415 volts = 26.96 amps. <<>> For a three-phase motor each phase supplies one third of the power, so that is 5 HP on each phase. A 415 v supply has a line-to-neutral voltage of 240 v, and 3730 watts would therefore required 3730/240 amps, or 15.54 amps. However due allowance must be made for (i) the power factor and (ii) the conversion efficiency. This would increase the current by an estimated 20% so the current is therefore estimated to be 19 amps.

Can you power a 3 phase 240 volts 20 ton air condition unit using the voltage settings 1 phase 127 volts 2 phase 127 volts and 3 phase 127 volts where between any two phases the voltage is 240 v?

If you have a voltage of 127 volts to neutral (ground) then your wye connected three phase leg voltages will have to be 127 x 1.73 = 220 volts. This voltage is within the 10% allowance for voltages as should operate the compressor. As the voltage is lower that specified, the amperage rating when a reading is taken will be higher than that of the equipments nameplate.

How many amps in 240 volts?

The question is not relevant. 240 volts refers to the "potential", and amps refers to the current. Potential * current = watts, or energy. You can have 240 volts at 1 amp, which will result in 240 watts, or you can have 240 amps at 1 volt which would also result in 240 watts.

What is KWH value of a 3 phase electric motor of 3.7 KW having power factor 0.86 and operated at 415 Volts for 1 hour?

3.7 kwh

When calculating kilowatts from known amps on a 3 phase circuit do you use 415 volts or the 240 line volts in the equation?

You can use either. I assume the 240 volts is the line to neutral voltage, and the 415 is the line to line voltages. They will both give you the correct answer. It is important to note these values are RMS, not 0 - peak voltages, but this may be beyond your question. The equations below are for calculated from RMS values (both voltage and current).If you are using a L-L voltage, P = I*V*sqrt(3)If you are using the L-N voltage, 1-phase power P = I*V (for the power in a single phase, for all three, multiply by 3), or 3phase power P = 3*I*VYou will get the same answer, since the L-N voltage is (1/sqr(3)) times the L-L voltage.

How does a 3-phase 115 volt power supply measure 200 volts in-between each phase?

Three phases are: 115 volts @ 0 degrees 115 volts @ 120 degrees 115 volts @ -120 degrees Just for comparison purposes, phase to neutral voltage is: (Phase) - (neutral voltage) = (Phase) - (0) = Phase voltage So phase to phase voltage is: (Phase 1) - (Phase 2) = (Phase 1) * sqrt(3) = (115) * 1.732 = 208 volts.

Is your house 120 or 240?

It is usually 240. Two lines enter your house, carrying 120 volts each, but they are out of phase by 180 degrees, so the two combined entering your house provide 240 volts, which is necessary for powering central air conditioning systems. You also have the option of powering everything else in your house with 120 volts because of the phase difference of 180 degrees without the need of a 2:1 turns ratio transformer in your house. You breaker box in you basement is wired to take advantage of this phase difference, supplying the 240 and 120 volt sources to the places that they are needed. This is a huge advantage of AC power.

Can you make 1 phase to 480 volts?

neon sign transformers are 1 phase 15,000V

How many amps required to run air conditioning 20 tons 3 phase?

1 ton of air-con is defined as 3577 watts Therefore 20 tons is 71.5 kW. On a 240 v 3-ph system the current for that is 100 amps, assuming a 240 v line-to-neutral voltage, equivalent to a phase-to-phase voltage of 415 v.

How does the 240 volts coming into the house become 120 volts?

The 240 volts coming in is coming from two separate 120 volt lines (phases). In your home, it's called single phase, although it really should be called two phase or double phase. In the box, there are two "hot" wires coming in, and one "neutral" wire. You add a ground wire to that yourself (check local codes). Basically (this is very simple description), one of the hot wires gives 120 volts, and the other gives 120 volts, but just a little bit behind the first phase. If you pull the cover off your electric panel, you would see two "hot" wires connected to two separate 'bus bars'. Every other slot on the left side of the breaker box is connected to hot 1, and the alternate slots are connected to hot 2. When you need 240 volts, the breaker you install will take up two slots, adding the 120 (hot 1) plus 120 (hot 2) to give you 240. For your regular plugs, a single slot breaker will deliver 120 volts. If you have a 240 volt plug, it will normally have 4 prongs. Two of the prongs have 120volts each (relative to ground) and 240 volts relative to each other (due to the lagging/leading phase difference.)

Can you run a 208 volt single-phase computer off 240 volt power?

No. The 1-phase 240 setting on your computer's power supply is for the 240V wall outlets in other countries. The 240 outlets in your home are 2-phase 240.

How much Ampere when volt 415?

That would depend on the power output (watts) of the circuit. Volts times the Amperage equals the Wattage of the circuit. You do not have enough information in your question. Volts is the force applied to move the electrons in the circuit, and amps are a measure of the quantity of electrons moved through the circuit over time. Thus a circuit of 415 volts and 1 ampere will deliver 415 watt-hours of power. Yet a circuit of 1 volt at 415 amps will deliver the same 415 watt-hours of power, but with less force.

Can you use 120 volts on a 240 volts water heater?

Yes, it will give you only 1/4 of of its rating

What formula is used to find amps when hp and volts are known?

For a single-phase induction motor, allow 7 amps on a 240 v for a 1-HP motor. Therefore the formula is: current = 7 X HP x 240 / voltage

What is the phase current of a three phase 2.2kw 415v motor connected in star?

The line current would be the same if the motor were connected in delta. The current can be based on the rule of thumb which says 7 amps must be allowed for a 1-HP single-phase motor on 240 v. A 2.2 kW motor is three times as powerful, and on a three-phase supply of the same voltage (240/415) it would draw 7 amps.

What transformer do you need if you have primary voltage of 600 3 phase and require 240 volt 1 phase?

A single phase 600 to 240 Volt transformer using two phases of the three phase primary.

If 1 phase 240 is used to power a piece of equipment that should be powered by 3 phase 240 will it damage the equipment?

odds are it is a motor and that would be yes

How do you convert 480v single phase to 240v single phase?

Answer for USA, Canada and countries running a 60 Hz supply service.To convert 480 volts single phase to 240 volts single phase you will need to use a step down transformer. Any two legs of a three phase system is classed as single phase. The primary side connection will be any two legs of a 480 volt three phase system. H1 to H2 will be 480 volts. On the secondary side of the transformer the connections will be X1 to X2 which will give you the required voltage of 240 volts single phase. Depending on what the secondary side load current draws will govern the size of the transformer.The formula to calculate the transformer size is KVA = Amps x Volts/1000.Connect a 2:1 ratio step-down transformer across any two line conductors of the three-phase supply, and the secondary will provide a 240-V single-phase supply. Unless you are qualified to do so, don't do this yourself, because the circuit will require the installation of overcurrent protection devices such as fuses or circuit breakers, in accordance with the relevant regulations, to make the installation safe.

How many amperes are there in 120watts?

It depends on how many volts there are. Watts = amperes times volts. If there were 120 volts, there would be 1 ampere. If there were 240 volts, there would be 0.5 amperes. If there were 12 volts, there would be 10 amperes.

Can 1 phase be used with 3 phase?

If you have a 208Y/120 volt 3 phase system, you can use any one of the three phases (hot or ungrounded conductor) with the neutral for 120 volt load or you can use any two phases of the three phase for a single phase 208 volt load. If you have a 120/240 volt 3 phase system, you can use any two phases of the three phase for a single phase 240 volt load or you can use either the A phase or C phase with the neutral for a 120 volt load. You can not use the B phase with a neutral (you would have 208 Volts!).

How many amps does a 1 hp 240 volt single phase motor draw?

It is best to use the nameplate amperage for accuracy. The code book says it is 8 amps at 230 volts. ======================= on a single phase , LINE x with NEUTRAL. to acquire amps. you divide wattage by voltage to get INTENSITY = AMPS. 1 hp equals 746 watts divided by voltage 240 = 3.10 AMPS

How many amps does the 1HP motor require?

A 1 HP motor is represented as 746 watts for calculation purposes. It depends on the voltage that the motor needs. Without a voltage the equation for single phase amperage calculation, Amps = HP x 746/Volt x Eff. x pf is not usable.For three phase amperage calculation a voltage is also needed, Amps = HP x 746/1.73 x Volts x Eff. x pf.Eff. is the efficiency of the motor and pf is the power factor of the motor.For calculation purposes the electrical code book uses 16 amps at 115 volts and 8 amps at 230 volts for a single phase 1 HP motor.For calculation purposes the electrical code book uses 4.8 amps at 200 volts, 4.2 amps at 230 volts, 1.8 amps at 460 volts and 1.7 amps at 575 volts for a three phase 1 HP motor.As always, if available, always use the motor's nameplate rating for any calculation.

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