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Electrical Wiring
Ask questions here about proper wiring and electrical installation here.
4,935 Questions
Can a 230 460 volt 3 phase motor be connected to a 277 480 volt 3 phase circuit?
Yes, that's possible, but only for low-powered motor.
You know that in order to start, the stator must be supplied with voltages that are shows shift phase between them,
so the trick is to use a capacitor (since it shifts phase current) to simulate a 3-phase source.
As indicated in the following picture:
http://freecircuitdiagram.com/wp-content/uploads/2010/10/Enabling-3-Phase-Motor-Operates-with-Single-Phase-Supply.gif
What is the reason for a neutral wire becoming energized and the circuit breaker not tripping?
=== === This is known as a "Disconnected Neutral (Open neutral)" fault condition. It occurs whenever the Neutral wire for a circuit becomes disconnected from the household's main power supply panel whilst the Live or "hot" wire for the circuit still remains connected to the panel AND the circuit has appliances plugged into the socket outlets.
In that situation, if you put a voltage indicator, such as a test screwdriver with a neon lamp onto the Neutral wire it will glow just as if it was Live, because it is being fed with a very small current coming from the Live supply via the plugged-in appliance(s) to the Neutral wire.
If you unplug all appliances, lights and whatever else may be connected to the circuit, the Neutral will no longer seem to be Live because there is no longer any path from it to the Live supply.
No ordinary circuit breaker on the main supply panel would trip in this situation because the current flowing from the Live via the appliance(s) to the Neutral to the test instrument is not high enough to cause the circuit breaker to trip to shut off the current.
Even if there is a GFCI or an RCD in the circuit that too is unlikely to trip in this situation because the test current is so small and is of the same size - an equal current flow - in both the Live and the Neutral wires.
A "Disconnected Neutral" fault condition is VERY UNSAFEbecause somebody who does not know about the danger could easily touch the Neutral wire and get a bad shock whilst trying to find out why no appliances work when they are plugged into a circuit that actually has such a "Disconnected Neutral" fault condition.
Hence a "Disconnected Neutral" fault is a very unsafe condition and should be corrected at the earliest possible opportunity by someone who knows exactly which wires to check and then connect properly.
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For your safety and that of anyone else who may to use the appliance, ask a professional licensed electrician to advise you or to do the work for you. If you do this work yourself, always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work AND
always use an electrician's test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to insure the circuit is, in fact, de-energized.
: IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
What is the use of capacitor in three phase induction motor?
Only Single phase induction motors need capacitor to star it, because of single phase.
With the help of capacitor in the starting winding circuit it is easy to create rotating magnetic field inside motor which is responsible for running of motor.
How does a shunt trip relay work?
A shunt capacitor creates a low resistance path in a circuit so that electricity can pass around to another point. Shunt capacitors create shorts when they receive abnormally high amounts of voltage to correct series circuits.
How can you get 208V single phase from a residential service?
There are buck-boost transformers available that will do just that. I don't know about the buck-boost transformers, but most residential service is 110/220 single phase. The phase is split at the transformer that feeds the house from the power line. You will often see appliances marked with a voltage of 208/230 or something in that rang. So you should have single phase 110/220 volt already. Hope this helps, waterman@bluemarble.net. You cannot get 208V directly from residential service. 208V is usually found in 3 phase commercial/industrial supply. You can get 240V, as mentioned above, between the two hots of residential service. Check the ratings on your device to see if that will work, keeping in mind the device must be able to handle a minumum of 250VAC for that to work.
What is the difference between single phase and three phase electrical power services?
Answer for USA, Canada and countries using similar 60Hz household electricity supplies This is a very simplified answer: Single-phase has two hot "legs". Each are 120 V. for a total of 240 V. A neutral wire (white in color) will give you 120 V. When straight 240V is needed, a neutral isn't necessary. 3-Phase has 3 hot legs for a total of 480V. This voltage is generally used for motors in industrial and commercial settings. This voltage can be "stepped down" via use of a step-down transformer. This converts 480V into 120/208/277. 120V is used for common appliances. 208V can be used for dryers and ranges (if they're rated for 208). 277V is used for lighting circuits (again, lighting must be rated for 277V). 3-phase is used in commercial and industrial, including schools. A neutral is needed for 120V and 277V and is generally gray.
For more information see the answers to the Related Questions shown below.
Is there such a thing as Gauge 0 wire?
It is quite possible that this question "Gauge 0 wire?" was actually meant to be an Answer rather than an Alternate-Wording-To the original question, from which "Gauge 0 wire?" was split away: "What wire gauge is used for an electric range?".
If that is so, then a comment to the suggestion that Gauge 0 wire might be suitable, is that insulated Guage 0 wire is very thick indeed and would not often have to be used in wiring for normal domestic use in homes. Even for high-powered appliances, such as 240 Volt kitchen ranges or clothing dryers, Guage 6 wire would usually be thick enough to be used safely for the kinds of lengths of runs needed in normal size houses.
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What exactly is being asked by this question "Gauge 0 wire"?
Is it about some mechanical work? (Making a cage for an animal?)
Or what diameter Gauge 0 wire is?
Or of what kind of material Gauge 0 wire usually comes in?
Or is it asking if Gauge 0 wire is the right size to use in some electrical work?
(Like how many Amps can it carry safely without overheating?)
- One factor to decide the wire guage is the length of the run from the main circuit breaker panel to the appliance because, the thicker a wire is, so the lower its electrical resistance is. That is why, to prevent the wire from becoming hot enough to start a house fire, for a long run the wire has to be much thicker than for a short run.
- Common house wiring for lighting circuits can be 12 or 14 guage.
- Wiring to supply a high-powered 240 volt kitchen range or clothes
- A dryer may have to be 4 or 6 guage but the actual size needed Always depends on the length of the run.
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself
on electrical circuits, equipment or appliances
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
Why do you try to balance single phase loads on a three phase four wire system?
Because all electrical supply systems are designed to A specific amperage delivery. If you are set up for 1000 amps 3 phase, That means that you are getting 350 amps each on three legs. If you put all your single phase (110volt) stuff on the same leg and have A total of 300 amps of draw then when you try to use several 110 volt items and A three phase piece you will draw too much power on one leg causing an overload. Even though you may only be using A total of 400 amps. Something will give, Most likely the fuse or breaker.
How do you get 277 volts from a 480 volt line?
All three phase four wire systems have the ability to produce a voltage to ground or neutral. Take any phase voltage be it primary or secondary and divide it by the sq. root of 3 which equals (1.73) and you will obtain the phase to ground or neutral voltage. The ground and neutral should be of the same potential and when talking about electrical installations these two words get interchanged quite often. Some three phase secondary voltages are 208, 480 and 600 volts. Electricians will talk about voltages of 120/208, 277/480 and 347/600. The first number is the phase to neutral voltage and the second number is the phase to phase voltage.
What problems will you have if you run a 110v appliance on a 240v circuit?
it wouldn't work long it would keep popping breaker and possible to cause a fire if keep reseting the breaker
110v would not be enough to power 220v. It wouldn't harm the appliance but it will not keep popping breakers. However, plugging 110v equipment into 220v outlets will destroy the appliance.
You can cause damage to the equipment, at least if there is a motor in it. The 110v will be insufficient to turn the motor, so the current passing through it will remain at the level of the startup surge (ever notice how the lights in your house dim slightly when the air conditioner compressor kicks on?). For a short duration, like a normal startup, this surge will not do any harm, but if that much current is allowed to continue coursing through the coils, they will quickly overheat.
Never let the smoke out of the motor!
How do you measure voltage in a 3 wire single phase system?
For a three-phase, four-wire, system, the line voltage is measured between any pair of line conductors, while the phase voltage is measured between any line conductor and the neutral conductor.
For a three-phase, four-wire, system, the line voltage is numerically-equal to the phase voltage, and both are measured between any pair of line conductors.
It will probably run but not correctly. Low voltage will cause the motor to draw less amps than it's designed to. It will not reach its rated RPMs and such slow operation may shorten its operating life.
20KW machine 480 volts 3 phase what is the amps?
You really need to know the line voltage (VL) involved. Provided the load is balanced, to find the line current, you need to divide the load (in watts) by (1.732 x VL). Incidentally, the correct symbol for kilowatts is kW, not Kw!
How do you stop oil leakage in Transformer?
If you have a large power transformer that is leaking oil, do NOT touch it! Older transformer oil contains PCB's which are extremely toxic!! Get a licensed firm to test the oil for PCB's and repair or replace the transformer. Don't fool around with this! PCB's are a serious danger to you and others. Do not let this go. Get it fixed right away!
What factors contribute to the electrical resistance of a conductor?
1) What materials the conductor is made of;
2) the average cross-sectional area along the length of the conductor;
3) the temperature of a conductor also affects its resistance;
4) the length of the conductor is also very important.
Generally, the longer the conductor, the higher its resistance.
Your students' course materials can probably give you a better answer than mine, or at least you'll know it is the right one.
The length, the cross sectional area, temperature of conductor along with the intrinsic property called the specific resistance of the substance.
On the whole megger testing is a non destructive test. What happens is a DC voltage is applied to the device or winding under test. It is an insulation test to see is the insulation has been injured in any way to cause a short circuit when normal power is applied to it. On my megger there are 3 ranges 300V, 750V, and 1000 volts. Applying the proper voltage is essential to not damaging the device you are testing. Working voltages up to 240 volts should use the 300 range. Working voltages up to 600 volts use the 750 volt range and working voltages above 600 use the 1000 volt range. As you can see if you used the 1000 volt range on a device that had a working voltage of say 24 volts you could damage the insulation just by testing it. So meggering a device is non destructive if you use the tester as its instructions tell you to.
Power = E times I = (24 x 2) = 48 watts
How you convert the value of single phase power to value of 3 phase power?
Electric power is measured in watts. It does not matter if it is single phase or three phase. All things being equal, for the same load, the power measured in a single phase circuit or a three phase circuit, will be the same.
How do you calculate 3 phase kWh from measuring the total phase current current?
In a balanced 3-phase system, if the three loads are star connected, the line current is equal to the load current. If the loads are delta connected, the line current is less than the load current by a factor of 1/sqrt(3).
What are the disadvantages of transmitting electric power at high voltage levels?
The main disadvantage is that high voltage causes surrounding air ionization and may cause negative health effects for people close by. However, electric losses will be less when electricity is transmitted at high voltage. The higher the voltage the less the electric losses.
If a three phase motor loses one leg will it turn backwards before it burns up?
If a three phase motor loses one leg it will do neither of what you suggest. To change the rotation of a three phase motor any two motor leads must be interchanged. When one leg of a three phase system goes down it is said to be single phasing. The overload protection on the motor senses the higher current on the other two legs and trips the overload heaters. This in turn drops the contactor open and disconnects the motor from the supply.
What is the difference between an ordinary transformer and a center-tapped transformer?
An ordinary transformer has two input/output terminals but a center tapped transformer has 2 input and 3 output terminals. One is taken from the center for a ground connection. This causes it to get 50% of the actual value.
And ordinary transformer contains 2 windings.
An autotransformer has one.
Can you plug a 2 phase welder on a 3 phase plug?
No. Three phase service is something that you would need to request from your power company. You'd need to not only have service, you also need to have an electrician run 3 phase service into your home.
How are the windings of a star delta motor tested?
In a 3 phase induction motor there is 6 wires frm the windings.Inwhich ,we can measure ohms value between each other.there are 2 different ohms value between each pair of three wires.
lets say,10 ohm and 30 ohm.low voltage and high voltage side.can anyone say is it right to find the wingings of star and delta side?
How does a ground fault circuit interrupter shuts down a circuit?
A ground fault circuit breaker detects leakage current between the hot wire coming off the breaker and the neutral/ground since the neutral is bonded to the ground in the panel, if it senses a current of 6 milliamps or more it will trip. Note: no sharing of the neutral for a circuit on a ground fault breaker
If a few milliamps from the hot (black) wire do not return on the neutral (white) wire, then a GFCI assumes that current it traveling harmfully elsewhere through your body. So it disconnects. A GFCI can monitor 15,000 milliamps. But if only 5 go missing, then a GFCI trips.
