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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 between copper loss and iron loss in electrical engineering?
Iron losses occur due to nature of material this is of two types 1.eddy currents(circulating currents)
2.hystersis loss(nature of material)
Copper losses are due to amount of current flowing (given by I2R)
AnswerCopper losses are energy losses that occur in the primary and secondary windings, whereas iron losses are energy losses that occur in the core.
Which wire used single phase 240v 6.5kw load?
I = W/E. Amps = Watts/Volts = 6500/240 = 27 amps. A #10 copper conductor with an insulation factor of 90 degrees C is rated at 30 amps. If the load is continuous the conductor can only be loaded to 80% of its capacity. 30 x 80% = 24 amps which is too low for your load. Move to the next size wire which is a #8 which is rated at 40 amps x 80% = 32 amps. As long as no long distance runs are involved this wire size will work well.
The specific resisitivity - also called residual or inherent resistivity - of a particular material (scientifically called its specific resistivity) is measured in ohms per unit volume.
It can be determined by measuring the resistance of a test conductor having unit length and unit cross sectional area or some other accurately-measured volume of the material.
How do you convert fuel energy into heat energy?
When you burn the gas, it explodes, and creates energy.
Do induction motors work on the transformer principle?
Didn't work.because primary and secondary winding not in motor
AnswerYes. The rotor behaves as a rotating secondary winding -i.e. there is no electrical connection between the field windings and the rotor.
What is the Greek symbol for rsistance?
Electrical resistance is measured in ohms. The abbreviation is capital omega (Ω).
A current transformer (CT) works just like any other transformer. It is important to note it is not referenced to ground. It reflects current flow, not phase to ground voltage, so it attempts to hold current constant, not voltage.
There is usually one primary "winding": one large cable through a donut CT, and multiple secondary windings. If a secondary winding is shorted (a wire placed across its terminals), the voltage built up in the secondary will be equivalent to V = I*Z, where I is the secondary current, and Z is the impedance of the secondary winding, usually specified as some flat value plus so many ohms per winding.
If too big of an impedance is placed on the secondary, a voltage will build up to the point that the donut CT saturates, resulting in an output wave that has a large amount of harmonics. If the CT is open circuit\'d, voltage will build up until it is high enough to arc over (usually where it should have been shorted). CT\'s can be damaged by open circuiting them, so don\'t do it.
What appliances are connected to double circuit breakers used in the distribution panel?
240V appliances, such as range, dryer, air conditioner.
Why voltage of unit should match with grid when synchronising with grid?
If both the voltages do not match then there will be current fllow from higher voltage to low voltge, this is loss of power and can lead to even tripping of the system.
What is meant by equivalent resistance of a series combination?
Answer: The equivalent resistance of a series of resistors is as follows:
Suppose you have three 120 Ohm resistors:
A---/\/R1\/\------/\/R2\/\------/\/R3\/\---B
The equivalent resistance of point A to point B is the resistance of R1, R2 and R3 in series.
Suppose we would want to replace R1, R2 and R3 with a single resistor, R4:
A---/\/R4\/\---B
The resistance of R4 would be 360 Ohms, since equivalent resistance of a series combination is:
Req = R1 + R2 + R3
Answer: What is meant by equivalent resistance is that if you replace (for example) two or three circuits with whatever you calculate (see the other reply, above) as the "equivalent resistance", the effect on the circuit in general will be the same. For example, the same amount of current will flow.
What is the starter current draw?
Starter current draw refers to the amount of electrical current that an automotive starter motor consumes when it is activated to crank the engine. This current can vary widely, typically ranging from 100 to 300 amps for most vehicles, depending on the engine size and starter design. The high current draw is necessary to overcome the engine's inertia and initiate combustion. Prolonged or excessive current draw may indicate issues with the starter or battery.
Answering Which one is a separately excited generator - ac generator or dc generator?
Excitation is the phenomenon by which you control the excitation of field winding of a generator. In DC generator field winding is placed on stator and this field winding can be self excited or seperately excited depending upon the type on generator used. AC generators can also be self excited or seperately excited type but field winding is placed on rotor nad armature winding on stator.
A fan running at 1250 rpm and one running at 1750 rpm what giving delivering more cfm's?
1. ASSUMING AIR DENSITY AND FAN BLADE DIAMETER IS CONSTANT OR THE SAME --THE LATTER (1750 RPM) DELIVERS MORE CFM WHETHER BELT DRIVEN OR DIRECT COUPLED -- SAME HP RATING OF MOTOR. 2. 1250 RPM FAN CAN MATCH THE CFM OF 1750 RPM FAN --- CHANGE OR ADJUST THE PITCH OF 1250 RPM FAN BLADE. 3. 1250 RPM FAN CAN DELIVER MORE CFM THAN THE 1750 RPM FAN --- REPLACE FAN BLADE. 4. 1250 RPM FAN CAN DELIVER MORE CFM THAN THE 1750 RPM FAN --- REPLACE WITH BIGGER HORSE POWER.
What is the difference between line voltage and phase voltage?
The three 'hot' conductors supplying electricity to a three-phase load are called LINES, not 'phases' (although unfortunately the term 'phase' is widely, but incorrectly, used in the field).
Phases exist between line and neutral in star, or wye, connected systems, and between lines in a delta, or mesh, connected system. Accordingly, the term 'phase to phase' is quite meaningless.
A line voltage, therefore, exists between any two lines.
For a star (wye) connected system, a phase voltage exists between any line and the neutral conductor. For a delta (mesh) system, a phase voltage is exactly the same as a line voltage.
Why power at the secondary winding is less than the power at the primary winding?
If power were greater at secondary you would have an unlimited source of power. It is less because there are always losses in a transformer.
Because a generator extracts energy from whatever is rotating it and passes this (by the electric current it produces) down the circuit to the motor (or light bulb or heater) where it is used. When there is no complete electric circuit, no electricity can flow so no (little) energy is extracted, but when the circuit is closed, electricity does flow and the armature is more difficult to turn.
10 hp 208 volt 3ph 90 percent pf what is the amps squirl cage?
The formula you are looking for is I = HP x 746/1.73 x Volts x %Eff. x pf.
sdrg
What does a negative angle look like?
A positive or negative angle, refers to the directionthat you are measuring the angle. Not really useful in Geometry, where you're measuring angles of polygons, but in Trigonometry and Complex Numbers (especially signal analysis in Electrical Engineering) it becomes important.
In a unit circle, the convention is to measure positive angles in a counterclockwise direction starting at the positive x-axis. So negative angles are measured moving in a clockwise direction. In signal analysis, two sine waves are plotted with time on the horizontal, and intensity on the vertical. The sign of the 'angle' between the two signals represents if one signal is 'leading' ahead or 'lagging' behind the other signal.
Give the equation for determining the total impedance in a inductive and resistive circuit?
Simple addition, but it must be done with complex numbers.
