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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
What is line voltage in star connection?
Phase to phase voltage is 1.732 (the square root of 3) times the phase to star point (neutral) line voltage.
e.g. if the line voltage is 220V
phase voltage = 1.732x220 = 380V (approx)
Additional AnswerYou might also like to know that the line voltage leads the phase voltage by 30 electrical degrees. And, incidentally, the correct expressions are 'line-to-line' not 'phase-to-phase', and 'line-to-neutral' not 'phase-to-neutral' (think about it, a line voltage is measured from the junctions between adjacent phases, so they cannot be 'phase to phase'!)
What are three related electrical factors did George Ohm investigate?
the answer is current, voltage, and resistance
How much current flows through a circuit if the resistance is 15 ohms and there is a 3-volt battery?
E= ( I ) x ( R ) = (15 amperes) x (4 ohms) = 60 volts
Note:
When 15 amperes flows through a resistance of 4 ohms,
the resistance dissipates 900 watts. If it is not part of a
toaster or a blow drier, it either melts or explodes.
motors are rated in kw why because for motor the load is mechanical load. only active power converted to mechanical power is significant and in motor rotational losses,frictional and windage losses, we cant express these losses in VA, only expressed in KW. hence the motor rating in KW
-ashok(BE)
What vegteble conduct electricity?
carrots
broccoli
corn is a starch but it works too
peanut smeared on bananas also produce a moderate amount of electricity
What is a Megger 1552 used for?
The Megger MFT 1552 is a combined electrical circuit tester which includes test features for Insulation testing, Earth loop impedance tests, RCD Testing and Continuity testing. It comes supplies with full Calibration Certificate.
Can you change the direction on an ac motor?
A series DC motor can be thought of as having two components, the rotor and the stator. The rotor has windings which rotate and the stator's windings stay stationary. In a series DC motor these windings are connected in series. To make the motor turn backwards you must reverse the current through either the rotor or stator windings, but not both.
What is the full load running current of a 3hp 208volt single phase continuous duty ac motor?
It would probably be 20-30 amps.
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The electrical code book states a value of 18.7amps for a 3HP 208 volt motor. If the nameplate data is available it is always best to use it when calculating wire size and overload protection for the motor.
A measurement of electrical resistance. It is dimensionally equivalent to Volts / Amperes. (Voltage / Current)
AnswerAn ohm is the unit of measurement of resistance. Resistance is not affected by either voltage or current, but by the length, cross-sectional area, and resistivity of the conductor.
Why a full wave rectifier is preferred over a half wave rectifier?
The a.c. component, or ripple, produced by the 4-diode (full wave) bridge rectifier is the same as that produced by the 2-diode full wave rectifier.
The bridge is connected across the secondary winding of a transformer.
The 2 diodes of the other type of full wave rectifier are each connected to one end of a winding, but that winding requires a center tap.
For any desired value of d.c. after rectification, the a.c. voltage of the 2-diode rectifier winding has to be twice that of the winding required for the bridge.
What gauge wire run to panelbox as main power?
Another thought
Be careful. This question can have more than one valid answer. For instance, table 310.16 may apply in some circumstances, but if the 200A service in the question happens to be a single-phase service in a dwelling, there is a different table (310.15(B)(6) just for the purpose of sizing service conductors in that case. It indicates that 2/0 copper OR 4/0 aluminum would be the correct choice.
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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.
Do conductors have high or low current?
Low resistance.
Think of Ohm's law. Voltage drop is directly proportional to resistance. The higher the resistance, the higher the voltage drop, and the less voltage that is available for the load. Think of conductor resistance as a resistance in series with the load.
Also, higher conductor resistance means more power lost, going to heating the conductors. The "line loss" formula is P=I2R. The greater the resistance, the greater the electrical power being converted into thermal power heating the conductors.
200 amps is equal to zero kva. To answer this question a voltage is needed.
What happens to the power output of each lamp if more lamps are connected in parallel?
The lamps will get dimmer. In a parallel circuit, voltage is constant. Whereas, in a series circuit, amps are constant.
How do you change 25AMP into kw?
You don't. An ampere is used to measure current, whereas a watt is used to measure power. These are two different quantities, so you can't simply change one to another.
How can you stabilize a fluctuating voltage?
You can reduce the voltage fluctuations by first determining what is causing them, then counteracting this cause. In small circuit designs with multiple switching amplifier and ICs, the power or ground lines may become noisy due to this switching. Placing capacitors at the ICs power and ground can reduce this to manageable levels in most cases. Sometimes it can become necessary to isolate specific circuit's power and ground from the system using small inductors as well. If you are designing a power supply, zener diodes, and isolated power outputs (at the same or different voltages) can be used.
Why does your 2hp electric motor get hot?
The load of the motor itself is constant and it will try to achieve it's running RPM. If the supply voltage decreases the amperage needed increases to where the motor windings cannot sustain the current flow without producing excessive heat. Hence, SMOKE!
What is the use of Moulded Case Circuit Breaker?
A 'molded case circuit breaker' is a common designation for the circuit breakers used in the main electrical panel of most American homes.
The name is meant to infer that it is designed to never be opened, repaired, or modified. Replacement is the only option.
Who invented the electric kettle?
Which kettle do you mean? Or did you mean 'Who invented the kettle'? As with most cooking utensils, it is unlikely that a specific person 'invented' the kettle, since that sort of thing developed as necessary through the ages.
What is the current carrying capacity of 120 sq mm copper conductor?
1 sq..mm have max. capacity is 10 ampere if these are of copper approximately than 120 sq..mm having current carrying capacity is 1200 ampere
What is the difference between 220KV grid sub station and 132KV grid sub station?
An electrical power substation is a conversion point between transmission level voltages (such as 138Kv) and distribution level voltages (such as 11Kv). A substation has one or more step-down transformers and serves a regional area such as part of a city or neighborhood. Substations are connected to each other by the transmission ring circuit.
A electrical grid station is an interconnection point between two transmission ring circuits, often between two geographic regions. They might have a transformer, depending on the possibly different voltages, so that the voltage levels can be adjusted as needed.
The interconnected network of grid stations is called the grid, and may ultimately represent an entire multi-state region. In this configuration, loss of a small section, such as loss of a power station, does not impact the grid as a whole, nor does it impact the more localized neighborhoods, as the grid simply shifts its power flow to compensate, giving the power station operator the opportunity to effect repairs without having a blackout.
AnswerA 'grid' station is a substation -i.e. a compound or building containing transformers, circuit breakers, busbar systems, and protection system. The correct term is a 'grid substation', which is simply a substation which is part of the grid system -i.e. the transmission system. Other substations include 'primary substations', which interface the transmission system with the distribution system, and 'distribution substations' which could be as simple as a pole-mounted transformer.
How much resistance allows an impressed voltage of 6 V to produce a current of 0.006 a?
R=V/i
That is 1000 ohm.
How emf is induced in dc motor?
In brief,in a 3 phase SQIM,there are 3 windings per pole in the stator physically 120 degree apart,each of which is fed from per phase of a balanced 3 phase ac supply.As the magnetic field due to current in each winding varies with time as the current is alternating,the resultant field will be found to keep on changing its direction with time in a circular locus,magnitude being constant because of this setup which can be shown mathematically.Thus a rotating flux of constant mag links the rotor which induces an emf in the rotor,though initially both rotor & stator are static.
Another Answer
A three-phase induction motor is, essentially, a transformer. The 'primary' windings being the stator's field windings, and the 'secondary' winding being the bars of the rotor. For this reason, induction motors are often termed 'rotary transformers'. So emfs are induced into the bars by 'transformer action'.
Unlike a 'static' transformer, however, the secondary voltages and the frequencies of the voltages vary with the speed of the rotor.
Can you repair transformer 24v?
Hi,
24 volt control transformers come in all kinds of sizes and voltage options.
If you have a all electric system then chances are you have 230 volt A.C. primary to 24 V.A.C. secondary.
If you have a gas system I'm assuming 120 volt A.C. primary to 24 V.A.C. secondary output transformer.
The above two are in no case all there are out there but the most common in the H.V.A.C. field.
These small control transformers are typically rated in VA ratings.
Make sure your transformer is showing its full voltage potential reading under full load on the output 24volt A.C. side. If it is not , then you either have a transformer that is to small from some addition to your system or wrong transformer replacement in past. You can check the amperage output with a amproble if necessary on secondary side. It should not go above the name plate rating. If it does, check to see if your equipments literature or supplier & manufacture can tell you what original equipment was designed for this system.
Sometimes the transformer will hum when under heavy load. Whatever part of the system that started drawing power when this occurse is usually your culprit to your problem.
Transformers can just age and go bad. (OR just go bad period) if it hums alot then it has weakly wrapped windings which can cause insulation failure within the coil.
But please do remember most transformers get louder the closer they come to their nominal designed conditions.
Sometimes if your Amprobe will not pick up the small signal you can wrap a wire around the wire you are checking 10 times and connect at ends and it will magnify your reading x10 so you can see it on your amprobe.
Transformers usually really stink when they go down. They have a real sharp burned smell that stands out quiet strongly. So Use your nose.
Basically this is what you will see in most home situations:
central heat only=20 VA rating 24 volt transformer
central heat with cooling = 40 VA rating 24 volt transformer
Heat Pumps and dual fuel systems typically use =50va output ratings or sometimes 60 VA. because of all the extra devices they have to operate in the more complicated systems.
Remember any transformer should be seen and not heard if all is well.
Hope this helps: Jimiwane
Voltage dividers are used in a linear circuit to separate the input voltage into a small portion known as the output voltage. It is commonly used to get a low voltage signal equal to the voltage being measured.
