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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 the difference while applying kcl to dc and ac circuits?
KCL is Common to both AC and DC. Only the waveform or AC and DC will differ
Can a foot mounted motor be used as a flange mounted motor What will be the effect?
Trouble is to get it mounted right. It'd be very rare to find an assembly spot set up to accept both flange mount and foot mount. But assuming the motor spec is the same (power, RPM, etc) it'll work just find assuming you get the alignment right.
Are the lights in your school connected in series current or parallel current?
Overhead lights are typically connected in parallel. If they were connected in series, then, if one light went out, all of the lights would go out.
Think of Christmas lights, they are connected in series. When one of the lights burns out, the whole string of lights goes out.
What brand of microwave was the first to use a turntable?
According to a document from the Sharp Corporation (refer to the link below; n.b., it is a huge PDF document!):
"1966
R-600 Turntable Microwave Oven
Sharp developed the world's first microwave
oven to use a turntable, introducing it as
Japan's first consumer model."
What is the use of separatedly excited dc motor?
Excellent speed regulation is characteristic of this design which lends itself well to speed control by variation of the field current.
Separately excited DC motors can race to dangerously high speeds (theoretically infinity) if current to the field coil is lost. Because of this, applications should include some form of field current protection as an unprotected motor could literally fly apart.
Since the total capacitance for capacitors in parallel is the sum of the individual capacitances. I'm sure that you can work it out for yourself!
110v and the current is 10 a what is the resistance?
Resistance is Volts over Current
11 Ohm = 110Volt / 10 Amp
In electrical what is the oms low?
Voltage(E)=Amps(I) x Resistance(R) (ohms)
use this formula to solve for other two.
A circuit must be physically interrupted to measure?
This is a tough question to answer because you've forgotten to include WHAT electrical property you're trying to measure.
If you are trying to measure current through a closed, complete circuit with a multimeter, then yes. You must physically disconnect the circuit at the point you wish to measure, and then re-complete the circuit by connecting the leads of your multimeter to the points you just disconnected. (Please be sure the circuit is not energized before you disconnect the circuit!)
If you are trying to measure a voltage difference, then no. Just place the leads of your multimeter on the two points you wish to measure the voltage between.
As always when dealing with electricity, its safety first. Please do everything you can to protect yourself from electrical shock, especially if you're dealing with 120V/240V line voltages in a house.
How the process of change in magnetic flux causes induced emf?
According to Faraday's laws of electromagnetic induction, whenever a varving flux link with a conductor an emf is induced.
Can you run a 100 watt bulb with low voltage cables?
The cable voltage is set by the voltage of the supply and not by what is connected to it. But a 100 watt amplifier on a 120 v supply would draw less than 1 amp even at high volume.
What would it cost to run a 3 phase induction motor?
Depends on the size. You can go from a few hp to many thousands of hp.
How much current flows through a resistance of 300 ohms if the power source is 15 volts?
Ohm's Law
Voltage = Current x Resistance
Answer is 15/300
A phase wire is the hot wire in a circuit if looking at single phase that would be the live (brown in the UK). If you are trying to find out which wire is your phase wire use a voltmeter connect the black lead to earth and red lead on the wire to be tested. If the circuit is on and you have a phase wire you will read voltage on the meter. If the circuit is off or you have the neutral(blue wire in the UK) you will read little or no volts.
Notice electricity is dangerous always use common sense if you don't know what you are doing find someone who does failing that put a hand in your pocket you will have less chance of killing yourself.
Answer'Phase' is the incorrect name widely used in place of the correct term, 'line'. The current version of BS 7671(2008), the IEE Wiring Regulations, has, at last, recognised the misuse of the term 'phase' in its previous editions.
In the UK, a single-phase AC line conductor has a nominal potential of 230 V with respect to the neutral. In Europe, a single-phase line conductor is normally colour-coded brown; in three-phase systems, the three line conductors are colour codes brown, black, and grey.
Why slip test is carried on salient pole rotor alternator?
Objective:
To determine the direct & quadrature axis reactances of a salientpolealternator.
Apparatus:
1. Two A.C voltmeters
2. One A.C ammeter
3. Rheostats
4. A single throw triple pole switch
Theory:
The unsaturated values of Xd and Xq for a 3-phase synchronous machine may be
found by applying low values of balanced voltage to its armature, and driving its
rotor mechanically at a speed differing slightly from the normal synchronous speed,
the field circuit being open. The rotating armature m.m.f axis gradually changes, on
account of the 'slip ' between coincidenc4 with the polar & interpolar axes
successively. The reluctance of the magnetic circuit varies cyclically between an
upper & a lower limit, and the armature current consequently changes in the reverse
sense. The ratios of applied voltage to armature current gives the synchronous
reactances, using minimum ratio for Xq and maximum for Xd. Xd has the same
value as would be obtained from the normal no load and short circuit tests.
Procedure:
1. A coupled D.C motor very near to synchronous speed runs the salient- pole
synchronous machine. If the synchronous speed is 1500 rpm, the set is run at
1750 rpm.
2. The stator of the salient pole alternator is supplied from a low voltage (10-20
Volts), 3 -phase supply. The supply frequency is more than 50 Hz as the
supplying alternator is run at 1750 rpm.
3. The field is kept open and the maximum and minimum deflections in the
ammeter (to read the supply voltage) are read.
4. Xd, Xq are calculated.
Results:
Xd = Maximum V/Minimum I
Xq = Minimum V/ Maximum I
Discussion:
1. The alternator should not be run at exactly the synchronous speed, for then
instruments will give steady deflections. The stator voltage must be capable of
close adjustment. The slip must be very small. Otherwise the measurements will
be in error on account of eddy currents in the pole faces or the damper windings.
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If in the experiment, the slip is very large, and cannot be adjusted to a smaller
value, he measurements are liable to error.
2. The slip tends to pulsate because of fluctuation of torque with the relative pole
positions with the result that there is a tendency for Xd to be underestimated
What is self saturated magnetic amplifier?
an amplifier which is self saturated is called self saturated magnetic amp
What does the term bridging mean in electrical engineering?
In terms of electrical engineering, the term "bridging" refers to connecting a load to two amplifiers. This is done to increase the voltage. It can also refer to the use of an impedance with a low source to power an impedance with a larger load, again to maximise the voltage.
Why is a dc motor making a whistling noise at low speed?
There are many causes of such whistling noise coming from a motor. These includes but are not limited to:
- A broken brusher rubbing against the commutator.
- Loose bearings
- A damaged armature winding rubbing against the field windings.
What do you expect of ohmic resistance as you increase or reduce temperature?
It depends. In general, pure metal conductors increase in resistance as their temperature increases; some alloys (e.g. constantan) are manufactured to maintain an approximately-constant resistance for changes in temperature. Materials such as carbon (and most insulators) exhibit a fall in resistance as their temperatures increase.
When the voltage is in volts and the current is in amperes electric power is expressed in watts?
The formula that you are expressing is Watts = Amps x Volts. There are two other ways to express watts.
W = E (squared)/R and
W = Amps (squared)/R.
R is the resistance of a device in ohms.
What property term describes gold as conducting electricity?
The correct term is the conductivity of the metal. The conductivity of different metals can be found tables on the internet.
Examples are:
Silver (best) 6.30 x 10 to the power 7 S/m
Copper 5.96
Gold 4.10
Aluminium 3.50
Tungsten 1.79
Copper is the most widely used metal for electric currents. Silver is 6% better while aluminium is 31% worse. However aluminium is used for overhead power lines because it is lighter and therefore the pylons can be made using a less massive design.
