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Electrical Wiring
Ask questions here about proper wiring and electrical installation here.
4,935 Questions
Is there any difference in the power consumption by a same rating motor in 1 phase or in 3 phase?
The power consumption is the same in both cases. For a high-power motor it is more efficient to feed a 3-phase motor because the amount of power wasted in the wiring that feeds the motor is less, assuming the same size of wire.
Yes, you could connect these parts together and it would operate. But after awhile you will find that the batteries are running low and the will motor is run slower than initially.
The answer to the specific question is "no - you could not do this to generate electricity endlessly". If you could, that would constitute a perpetual motion machine, and that is impossible to do, due to losses in energy conversion because nothing is perfectly efficient.
What is the base unit of voltage?
The base unit of voltage is the volt, a combined unit meaning joules per coulomb.
AnswerThe SI unit for voltage is the volt (symbol: V), which is a derived unit -not a base unit. There are seven base units in the SI system: metre, kilogram, second, ampere, candela, kelvin, and mole. SI units which are not base units are termed 'derived units'.
What color is a computer ground wire?
Green or bare wire is used for ground conductors in US, Canada and countries which use similar wiring codes for 60Hz power supplies.
<><><> Green/yellow striped wire is used for ground conductors in Europe and other world areas which use similar wiring codes for 50Hz power supplies. IF YOU ARE NOT ALREADY SURE YOU CAN DO AN ELECTRICAL JOB
SAFELY AND COMPETENTLY
REFER THE WORK TO QUALIFIED PROFESSIONALS.
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.
Is line voltage or phase voltage mentioned on transformer nameplate?
It depends how they are connected. If they are connected between line conductors then they are measuring line voltages. If they are connected across phases then they are measuring phase voltages.
What are the dimensions of an English electrical plug socket?
In England they use Type G plugs and sockets for their standard household electricity supplies. For more information see the Related Link shown below and also the answer to the Related Question.
I am about to take this exam myself, so maybe I can help both of us with this.
The choices are:
A.) anode
B.) cathode
C.) deflecting plates
D.) grid
The answer starts on page 86 of your study guide, titled "Cathode Ray Tubes".
In this illustration, current supplied to the heater causes emission of electrons from the cathode. Those electrons pass toward the anodes through an opening in the control grid. The grid limits the number of electrons that can pass through it, and the anodes cause the electrons passing the grid to a point on the fluorescent screen. Also, two deflecting plates are placed in the path of the beam electrons. When a voltage is applied to these plates, the beam is deflected toward the positively charged plates. If the applied voltage is alternating, the beam moves up and down through its normal central position, and the luminous spot moves on the screen in the same way.
Based on this information I have deduced thus...
The answer is not A.) anode. Because the anodes job is to pass the electrons the grid allowed through to the point on the fluorescent screen.
The answer is not B.) cathode. Because the cathode when heated causes emission of electrons, its purpose is not to limit the number of electrons, just to produce the electrons. The answer is not C.) deflecting plates. Because their job is to use the emitted electrons allowed through the grid to make the projection. So, the answer must be D.) Grid. Because the grid limits the number of electrons that can pass through it!
Like I said, I have not taken this exam myself. However, based on the reading material, D just makes sense!
A three-phase motor has a rotating magnetic field inside that is set up by the supply, so the armature always rotates in the correct direction. A single-phase motor can in principle start either way so it has a starting winding supplied through a capacitor to provide a small component of rotating field to get it started the right way. After it has picked up speed the starting winding can be switched out.
How do star and delta configured three phase induction motors perform differently?
Star Delta starter control wiring ensures that initially the Motor winding is connected in Star and after set timer (few seconds) the winding gets connected in Delta automatically. There three power contactors and timers to make it happen.
How many contactors using in star connection of motor?
two contecter
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There are three contactors used in a Star Delta configuration.
Why twisted cables are in transmission line?
A twisted cable is two conductors of a single circuit that are twisted together. They are twisted together to cancel out electromagnetic interference.
How do you wire a 3 phase air conditioner?
The three phase supply first has to be connected through a three phase safety disconnect switch. From the safety switch the three phase supply then connects to the terminal strip that is supplied in the air conditioner's control panel. The air conditioner unit is factory wired so that all that is needed in external connections if the power and thermostat control.
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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.
How can a permanent charge by induction be created?
Inductance is the field created when sending a charge through a coil of wire. It's used for shunts in systems to prevent damage from shorts. So I guess if you could neutralize the charge between two coils with large capacitors ,bouncing the current back and forth like a doubler, it may be possible.
Iwant first year diploma in mechanical engineering ycmou model question paper set first semister?
YCMOU B.Tech. (Electronics Engineering) and
YCMOU B.Tech. (Mechanical Engineering) ==
Explain the difference between conductors semiconductors and insulators?
Metals are good conductors of electricity. Insulators are bad conductors of electricity. Similarly, semiconductor devices are partial conductors of electricity means their conductivity lies between conductors and insulators.
What is FLA in electrical terms?
FLA =
full load amps
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It is a term that is associated with motors. It is the amperage of the motor when it operates at its full rated horsepower under load.
Are all large motors three-phase?
Yes, most large motors are three phase. Usually single phase motors only go up to 10 HP. Larger than this and the wire size and contactors used to control the motors becomes extreme. For example a single phase 10 HP motor on 115 volts draws 100 amps. The same single phase motor on 230 volts draws 50 amps.
The same 10 HP motor on three phase system draws the following amperage; 230 volts is a 28 amp draw, 460 volts is a 14 amp draw and 575 volts is a 11 amp draw.
As you can see the higher the voltage becomes, the smaller the wire feeder size is needed and much smaller size contactor can be used to control the motor.
In order to determine power from volts and amps, we need to know the power factor and efficiency, but the question did not provide that information, so I will make an educated guess that the efficiency is 0.95 and the power factor is 0.92. The actual motor nameplate ratings will have to factor into the real calculations.
460 V times 120 A is 55.2 KVA. The question did not say, but it is assumed that the 120 A is per phase, so divide by 1.732 (square root of 3) to get winding power of 31.9 KVA, and then multiply by 3 to get total winding power of 95.6 KVA. Multiply by 0.92 and 0.95 to get power in watts of 83.6 KW.
If you want to know kilowatt-hours for 30 days, multiply by 30 and 24 to get 60.2 mega watt-hours.
How can a 240V single phase split ac work in the US which has a 120V 2 phase system?
Note
"2-phase" to describe US residential service is depricated nomenclature. US residential service is single phase because the two hot supply phases have 0 degrees of separation between their phases: therefore they are in phase.
The two phases are pulled from 2 out of 3 corners on a 240v (line-to-line) 3-phase delta-primary transformer, usually out in the street. (Sometimes at your house if it's a big one). Basically all power is generated and transmitted as 3-phase. Usually around 415V 3-phase comes into the primary of the 3-phase transformer. (It could be delta- or wye-connected.) The secondary windings for all three phases will each have a center-tapped connection, and that's grounded at the panel. This is the neutral wire. All circuits in houses return via the "common" or "neutral" wire to this point, which happens to be grounded at the panel. Note: no neutral wires should be grounded anywhere else. The two "corners" are 240v relative to each other, and 120v each to the center tap. Each 240V circuit really is two hot wires plus a neutral, which is why it's often wrongly called two-phase when in fact it's just single-phase. For each 120V circuit in the house you're going to use one hot wire and one neutral wire. The neutral wire provides a return path for currents back to the generating station. In some installations, such as apartment blocks, the third leg of power would be at 208V with respect to the center tap.
Another answer
Just what does "220v single-phase split ac in the US which has a 110v 2-phase system" mean?
The vast majority of electricity in the US is delivered as single phase or three phase. The only areas in the US that use 2-phase [for industrial and commercial purposes] are Philadelphia/South Jersey [where it is being phased out-no joke intended] and somewhere out west...
It was one of the early poly-phase options pursued because of the natural magnetic differential between phases [makes motors spin without a capacitor]
Most residences receive 220-240 volt single phase electricity with a grounded center-tapped neutral, the purpose being to limit voltage to ground to less than 150 volts from either "hot".
Can you connect a 3 phase motor to a 1 phase supply?
Single phase to three phase
The physical internal windings between single phase and three phase motors makes this an impossibility That being said money can make anything happen. Depending on the amount of money you want to spend to make this happen there is a device on the market called a VFD ( Variable Frequency Drive). On the three phase input terminals you apply your single phase voltage. On the output terminals you connect your three phase motor. When run in this configuration there is an internal switch that has to be changed to let the VFD know that it should be looking for only two lines on the input to be hot. Other wise the VFD thinks that there is a line loss on the three phase input terminals and the unit will not start.
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Some 3 phase motor speed controllers can be run off a single phase supply, this caused us a problem at work when a new speed control was fitted to some laundry equipment, as we then had to rewire the supply to bring in a nuetral, so i suggest a speed controller is probably the solution.
The formula to use is, phase voltage /1.73 = phase to neutral (ground) voltage.
CommentThere is no such thing as a 'phase to phase', or 'phase to neutral' voltage. The correct terms are 'line to line' and 'line to neutral'. So the above answer should read: line voltage/1.73= line to neutral voltage = phase voltage.
What is the equivalent resistance of two resistors of 1 ohm and 3 ohm connected in parallel?
35 ohms if they are in series as R(total) = R1+R2+R3
If they are in parallel then the formula is 1/R = 1/R1 + 1/R2 + 1/R3
Which in this case gives 2.86 ohms.
The total resistance when resistors are in parallel is ALWAYS LESS than the lowest individual value.
Where would you find a forward and reverse wiring diagram?
Are you asking about a wiring diagram for the right switches to make an electric motor turn either in a forward or a reverse direction? Or for a linear motor to go either one way or the other?
If so, please ask your question again and state what typeof electric motor you are asking about, because the direction-switching circuit needed will depend on the type of motor.
Some types of motors are not reversible at all.
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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.
Electrical wire splicing is the act of removing the outer shell of a wire, exposing the inside and connecting to another wire that is also spliced. This also allows you to add length to wiring.
Core balance current transformer?
whats a core balance current transformer?
Core Balance CTs are special CTs used to detect Earth faults & usually used for Restricted Earth Fault Protection.
It is a ring type CT through which the cables carrying current of all the three phases (R,Y & B) are passed through. (In a 3phase 3 wire system)
Under normal operating conditions, summation of current through the three phases shall be equal to zero. In event of a fault, the summation of the current shall no longer remain zero (zero sequence current shall flow during earth fault) & thus the fault can be detected.
