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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
3450
What are the advntage of the leading power factor?
A leading power factor means that the current is leading the voltage. That means that in the AC cycle (50 or 60 Hz) the current reaches its peak before the voltage. The amount of phase-lead can be up to 90 degrees which means one quarter cycle, or 5 milliseconds in a 50 Hz system.
How do you calculate full load current for 10000 KVA transformer?
Divide the VA by the voltage. But this transformer is probably a 3-phase one, maybe working on a 11,000 volt system, and in this case the live-to-neutral voltage is 6351 v and each phase supplies 3333 kVA. In this case the current supplied is 3,333,333 / 6351 or 525 amps on each phase. This is a common type of transformer in electricity supply.
Another Answer
Assuming you are talking about the secondary line current of a three-phase transformer, you simply divide the rated apparent power of the transformer by (1.732 x rated secondary line voltage).
Don't confuse line currents with phase currents. Line currents travel in the lines that connect the transformer with the load, whereas phase currents circulate within the windings.
For example, let's assume you have a 10 MVA primary distribution transformer, with a rated secondary line voltage of 11 kV. The full load current would be:
secondary line current = 10 000 000 / (1.732 x 11 000) = 525 A
The frequency must be the same and the phase must be the same as well. This can be indicated by having a lamp connected across the switch (for each phase if 3-phase).
What is the full load amps for 2.4 hp motor at 460 volts?
what is the full load amps for 2.4 hp motor at 460 volts ?
There is no such thing as a 'low power-factor' wattmeter. A wattmeter always reads true power, regardless of the load's power factor.
When one load is removed from a parallel circuit the total resistance decreases?
No, the total resistance increases.
How many litter par hour diesel consumption 30 kva generator?
Suppose the generator happens to be supplying 16 kW with an efficiency of 80% so that the mechanical load it places on the engine is 20 kW, the same as 27 HP.
A rule of thumb for a heat-engine is to allow 0.5 pounds of fuel per horse-power per hour, so in this case you would expect the generator to use 13.5 pounds of fuel per hour, which would be a couple of gallons or 9 litres if it is petrol, or slightly less for diesel.
What is equivalent of MW to Kva?
VA is the measure of Complex Power in a system which includes Real power(Watts, KW, MW) and Reactive power.
Direct answer to your question :
VA = Power Factor * Real Power (W Or KW Or MW)
Which type of motor is used in heat convector?
The fan in a convector is usually a single-phase induction motor.
Why leakage flux in transformer equivalent circuit is modeled as an inductor?
Because some of the primary flux fails to link with its own winding, the back- e.m.f. induced into the primary winding will be slightly lower than it would be had there been no leakage at all. We can account for this 'loss' of induced voltage as though it were caused by a small voltage drop occurring in the primary circuit, due to a small inductive-reactance connected in series with the primary winding. We call this the 'primary leakage reactance' (Xp).
A similar explanation can be applied to the secondary circuit, thus giving the secondary circuit a 'secondary leakage reactance' (Xs).
What is the necessary to know the polarity of voltage drop across a resistance?
Sometimes it isn't.
Another Answer
Voltage drops don't have polarity in the sense of a positive or negative charge. The term 'polarity', when applied to voltage drops, describe the sense or the direction in which that voltage drop is acting within the circuit. The rule is that a voltage drop always acts in the opposite direction to the current which causes it. An example of when it's necessary to know the polarity (direction) of a voltage drop is when applying Kirchhoff's Laws or other network theorems to solve a circuit
Extension ladder
How many amps will a 20 KW heat strip draw on 480 volt three phase?
24 amps. This could be three 11.54 resistors connected in star, or three 34.6 ohm resistors connected in delta.
What is an amortisseur winding?
An amortisseur winding is a squirrel cage winding placed near the surface of the pole faces of a synchronous motor.
Does a dc motor smell when running?
It probably smells a bit of oil when running but any smell of burning is a sign that something is wrong and it is liable to catch fire.
What tool is used to conduct insulation test of electric cable?
Strictly-speaking, this instrument is called a 'megohm meter', but is widely-known as a 'megger' which is the trade name of the company that manufactures the instrument.
What precautions should be taken during the start-up of a synchronous motor?
- Reduce the speed of the stator magnetic field.
- Use an external prime mover to accelarte the synchronous motor upto synchronos speed.
- Use damper windings.
Without knowing permissible current draw by the divider or its maximum power dissipation the actual resistor values cannot be determined, but the ratios of the resistor values can be determined from the required voltage drops.
The divider will be composed of 4 resistors starting at the 10VDC rail:
- 2VDC drop, ratio = 2V/10V = 0.2
- 3VDC drop, ratio = 3V/10V = 0.3
- 3VDC drop, ratio = 3V/10V = 0.3
- 2VDC drop, ratio = 2V/10V = 0.2
Therefore you will need 2 resistors (R1 & R4) that are 0.2 * the total resistance of the voltage divider and 2 resistors (R2 & R3) that are 0.3 * the total resistance of the voltage divider.
But as stated at the beginning you can get no further without additional requirements being specified.
What is a system of connected elements such as raillines?
A system of connected elements such as rail lines is a type of bond. This is to connect the 2 main route.
