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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 digital multi meter setting should be used to measure voltage?
There are settings for AC and DC voltages. If they are not marked as such, the DC setting might be parallel lines and the AC marking may be a cycle of a sine wave (Wavy line).
What happens if you connect the neutral of your home to another transformer's neutral?
If you independently connect two different neutrals together, you violate the star concept that protects the grounded neutral. While neutrals are all grounded, their relative potential voltage could be sufficiently different that connecting them together could cause large eddy currents that might cause overheating and equipment damage. Neutrals in one system are only allowed to be tied together at the distribution panel serving that system, and inter-system cross-ties are not allowed. Violation of this rule causes violation of the principle that is embodied in Kirchoff's Current Law, i.e. that with only one path to ground, any current on ground must represent a fault - cross tying systems together prevents detection of that fault, along with introducing eddy currents.
An ampere hour (A.h) is a non-SI unit of measurement for electrical charge (the SI unit is a coulomb-which is equivalent to an 'ampere second'). So an ampere hour is equivalent to 3600 coulombs.
Cells and batteries are generally rated in terms of ampere hours, as a convenient alternative to the kilocoulomb.
How do you convert kvr into kw?
The correct symbols for reactive kilovolt amperes and kilowatts are kvar and kW, respectively.
The simple answer is that you cannot convert one to the other. A reactive volt ampere is a measure of reactive power, and a kilowatt is a measure of true power. While these are related, they are different quantities, so you cannotconvert one to the other, any more than you can convert a kilometre to a kilogram.
Which supply has polarity AC or DC?
DC has polarity, while AC is constantly reversing in polarity.
AnswerWhile the previous answer is quite correct in the sense of 'positive' and 'negative' charges, it's worth pointing out that 'polarity' has a second meaning in a.c. systems.In a.c., the term 'polarity' is used to describe the correct connection of the supply's line and neutral terminals. For example, with an Edison screw lamp holder, to remove the risk of shock, it's important that the line conductor is connected to the centre terminal, and the neutral conductor is connected to the outer terminal. If this has been done correctly, then we say that its 'polarity' is correct. Similarly, if the terminals of a socket outlet (receptacle) are connected the correct way around, then their 'polarity' is correct. Testing for the correct connections in an a.c. electrical system is called a 'polarity test'.
What is the cable size to take a load of 95kw?
It depends on the voltage, which was not specified. Please restate the question, giving the voltage. The reason for this is that cable size is a function of current, not power.
AnswerThe size of a cable depends on the material from which the conductor is made, the number of cores, the type of insulation, whether it is armoured or unarmoured, and how it is installed. So, even if you know the relevant voltage, the only way in which you can determine the correct cable size is the use the tables provided in your country's wiring regulations, which take these factors into account. Incidentally, the symbol for 'kilowatt' is kW, not 'kw'.
How do you disconnect ammeter from current transformer?
A CT's secondary winding must never be open circuited as it may provide a shock hazard to the user. The terminals to which an ammeter is connected to a CT is normally provided with a set of links that must be closed, short-circuiting the CT, beforethe ammeter can be removed. The ammeter must the be reinstalled before the shorting links are reopened.
Why 2 holes are drilled oppositely in disc of energy meter?
To over come creeping effect on no-load, 2 holes are drilled on the opposite sides of the spindle. This causes sufficient distortion of the field to prevent rotation when one of the holes comes under one of the poles of the shunt magnet.
Courtesy - Industrial Instrumentation and Control
Is AC voltage measured from Peak to Peak or from 0 to peak?
Both. When an AC voltage is measured and a number is reported, it is necessary to state that this number is rms value or peak value or peak to peak value.
AnswerVoltages and currents are each normally expressed in root-mean-square (rms), unless otherwise stated. For example, when we talk about a '120-V service' or a '240-V service', we are expressing the voltages in rms values; it is unecessary to specify that these are rms values. For a sinusoidal waveform, Vrms = 0.707 Vpeak
What is the function of rheostat in this experiment?
A rheostat is the name given to a variable resistor when it is used to control current. When a variable resistor is used to control voltage, we call it a potentiometer.
A rheostat is connected in series with a load, and two of its three terminals are used. A potentiometer is connected in parallel with the supply, and each of its three terminals are used.
So the terms 'rheostat' and 'potentiometer' are the names given to describe the function of a variable resistor, not the variable resistor itself.
What is difference between isolation transformer and earth protection relay?
An isolation transformer is a mutual transformer having a voltage ratio of 1:1, so that the secondary circuit is electrically isolated from the primary circuit, yet subject to the same voltage.
An earth protection relay is a category of protective relay that responds to an earth fault monitored by a current transformer (CT). In the event of an earth fault being detected by the CT, the relay with activate the trip circuit to a circuit breaker which will then disconnect the fault.
What do you mean by electrical engineer practitioner?
One who practises the profession of electrical engineering. An electrical engineer.
What is the purpose of the holding circuit in a magnetic motor starter?
It hold the main contacts closed until the control circuit through the interlock is broken.
What advantage does the current definiton of the meter have over the 1793 statement?
- I have no idea! Answer it yourself you bafoon!
- Go to google
- Type your question
- be all girly happy
What would happen if a lamp was unscrewed from a parallel circuit?
There will be no change, because it is a parallel circuit.
How can you rotate the motor in anti clockwise direction?
Assuming (probably incorrectly) that you are talking about car engines:
It probably depends on the engine, and I question why you would ever want to rotate an engine in the opposite direction from how it is designed to run. But if I wanted to move an engine in the wrong direction, I would put a socket wrench on the front of the crankshaft, generally in the middle of the engine's lower pulley. I would first disconnect the negative battery cable, as you never want to risk the engine starting to fire and move on its own when you are working on it.
These generic hints would work on most traditional front engine rear wheel drive american car engines of the 50's thru 70's and beyond. (also on some Volvos, Suzuki Samurais, MBZ, and BMWs I have worked on.)
What is zero voltage regulation in transformers and what it means?
'Zero voltage regulation' indicates that there is no difference between its 'no-load voltage' and its 'full-load voltage' -this is only the case for an 'ideal' transformer.
Why tapping is necessary in a transformer?
Taps are connections to the (usually) high-voltage winding of a transformer which enables minor changes to the turns-ratio to be made in order to make minor changes to the secondary voltage to compensate, where necessary, to a fall in terminal voltage below the regulatory allowance.
There are two types of tap-changing mechanism, 'off-load' and 'on-load'.
Off-load tap-changing mechanisms require the transformer to be isolated before its tap settings can be adjusted, and is normally the case with smaller distribution transformers.
On-load tap-changing can be performed with the transformer supplying its load, usually automatically, in response to changes in its secondary voltage. On-load tap changing mechanisms have a 'make before break' switching arrangement, to ensure that the transformer windings are not open circuited during the operation of tap changing.
What is shunt current and a armature current?
The terms 'shunt' and 'armature' apply to a particular type of d.c. motor, in which the field windings are connected in parallel with the armature windings. 'Shunt' is an archaic term for 'parallel', so the term 'shunt', in this context, means that the field winding is connected in parallel with the armature winding. The terms 'shunt current' and 'armature current', then describe the currents flowing in the shunt winding and armature winding, respectively.
What is a frequency changer substation?
These are the substations which can have the capabality to change Frequency which it gets from the generators, human interventions neccessary to accomplish this task.
What is the dielectric constant for servo prime 46 lube oil?
ISO-VG 46 oil is a synthetic polyalkenglycol (PAG) oil, therefore the dielectric constant is 6.6-7.3. Please confirm the oil type of Servo Prime 46 lube oil see the chart in the related links section.
Servo Prime 46 is an ISO-vg46 oil made by Indian Oil Corporation Limited (IOCL).
It is also available from these manufacturers:
BPCL (hydrol 46)
Castrol (Hyspin AWS 46)
ExxonMobil Co. India Pvt. Ltd. (MObil DTE Medium)
Shell (Shell Turbo Oil T46)
What is the maximum current of the pole changing motor when running at low speed and high speed?
The maximum current of the pole changing motor when running at low speed and high speed depends on a few different things. The average when begin at low speed and using high speed is 1800 RPM points.
Can you measure power with a volt meter?
No. A voltmeter measures potential difference (voltage). To measure power, a wattmeter is required. On the other hand, for a d.c. circuit only, you could use a voltmeter and an ammeter, and multiply their readings in order to calculate the power of a load.
How do you calculate European Efficiency Factor in Broiler performance?
(((avg body weight X 1000)X(100%-mor%))/(FCR actual X meanage)) X 10
