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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
How to figure out ampreage in a circuit?
For a d.c. circuit, you divide its supply voltage by the resistance of its load. For an a.c. circuit, you divide its supply voltage by the impedance of its load.
What is the cable size for 55 kva genset with cable length of 56 meters?
To answer this question the voltage of the genset is needed.
If the excitation of generator changes what happens to the terminal voltage?
By Decreasing the excitation voltage the terminal voltage will decrease and similarly by increasing the excitation voltages the terminal voltage will also increases.
What is mean by no load condition?
Commonly relates to devices or equipment which are designed to do some task involving delivery of power, electrical or mechanical. The receiver or this power is called the "load" (for example, a light bulb, or a public lift activated by a motor). If such a load is disconnected (electrically or mechanically) then the arrangement is said to be in a "No Load" condition, and in some cases this might result in some electrical or mechanical failure of the power provider, possibly permanent. Good equipment is designed so that such failures do not occur.
How are the voltage drop across R and XL related in series RL circuit?
Voltage drop across a circuit is IZ, where I is current and Z is impedance. In other words IZ = IR + jIX, where R is resistance and X is inductance
A device or circuit that provides power to the rest of the circuit or system is called what?
A device or circuit that provides power to the rest of the circuit or system is called a power supply,
Can a 3 phase contactor be wired for single phase?
Yes, L1 of the single phase supply is terminated under terminal L1 of the three phase contactor. L2 of the single phase supply is terminated under terminal L2 of the three phase contactor. A conductor from output terminal T2 is then taken to input terminal L3. The single phase load is then connected to the contactor's output terminals T1 and T3. This incorporates all three of the overload blocks on the contactor into the control circuit. With the overloads in the control circuit, if an overload occurs the magnetic contactor's holding coil will drop out and take the load off line.
Depends on what you're offloading, exactly. If it's something which can be taken off by hoist or forklift, then it's a simple as that. If it's equipment being driven off, then you have to detach the neck, and drive it off the front of the trailer deck.
What is the role of magnetizing current in transformer?
connect 3 - phase supply to transformer primary winding.....keep transformer secondary winding open..... apply 3-phase voltage i.e.400v ac, and measure the amount of current flowing in each phase of the transformer primary winding...this current is the transformer magnetising current..... we can keep multimeters in series with the source....so we can measure directly the current readings.....(keep multimeters in current mode, and generally magnetising current will come in terms of milli amps for 400 v )
What is the function of monitoring voltage relay?
A voltage monitor relay is in the circuit for one reason. It monitors the incoming voltage to the equipment that it is protecting usually on three phase control panels.
The relay monitors the three incoming line voltages and in some relays the voltage to ground (wye connection). If the circuit the relay is protecting looses one of the voltage legs, the circuit will shut down until the problem is rectified. This usually happens if a fuse blows in one of the three phase voltage legs.
It also monitors the level of voltage to the circuit. If the voltage drops due to a malfunction in the utility lines the relay will trip and take the protected circuit off line. The voltages can be set to trip at any under or over voltage usually by set point controls on the front of the voltage monitoring relay.
By how many amps may a three phase motor exceed its data plate rating?
On a normal three phase motor on the nameplate there is a value in the S.F. box. This is the service factor. Depending on the size of the motor this value will vary. Smaller size motors usually have a service factor of 1.15
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See related links below.
What is it meant by adaptive problem of control system?
u should ask miss goay... but ask after 7 December 2007
How fast does a 3 hp motor go?
A 3HP motor can reach speeds up to at least 30 mph depending on what you are using it for.
The term Hertz (abbreviated Hz.) is used to describe the frequency with which current changes its' direction of flow in a second. Such as, our system frequency is 60 Hz.
When you double your distance from a speaker you lose how many db?
Sound pressure is inverse square law for distance, so doubling distance from a speaker cuts the power by 4. Since the db scale is 3 times log2 (power ratio), a reduction of power by 4 represents -6db.
What does a step-up transformer step up?
A step-up transformer steps up the voltage rather than stepping down the voltage like a normal ac wall adapter does. By stepping up the voltage it is not free electricity it allspice takes away from the available amps.
e.g.
Say you have 12V 1A AC going in to the primary coil of your step up transformer, this would result in a higher voltage and lesser amps like 24V 0.5A AC coming out of the secondary coil.
AnswerA step-up transformer steps up voltage, but it DOES NOT 'step down' current! The secondary current is determined by the load, and the primary current is then determined by the value of secondary current.
What is percentage reactance of a power system?
If the load on an AC system is purely resistive, then the voltage and current waveforms will be in phase. A desirable state.
When the load has some reactance, then these two parts of the power signal will not be in phase; and this results in an inferior power generation, in which some of the work needed to generate the signal is not available as real work at the terminus. This undesirable condition occurs with both inductive loads such as electric motors, and capacitive loads, such as fluorescent lighting.
This may be corrected for in real-life systems by employing 'power factor' correcting equipment. One common device is the 'rotary capacitor' - in reality, a rotating transformer in which the phase is controlled as to make it appear as a capacitor, not as an inductor.
Ordinary transformers transfer the reactance of their load, with a small percentage of genuine reactance due to hysteresis losses in the core of the transformer.
"Motor control" generally refers to the physical dexterity of a human or other animal.
It is primarily affected by two things:
Physical condition: general bone/muscle structure
Mental condition: ability of the brain to interact with the muscle system. Typically divided into rapid motor control (ability to create rapid gestures that cause significant motion) and fine motor control (the maximum level of precision that can be achieved)
What is electro-technical coupling and please give an example of a product that uses it?
This is probably a homework or exam question.
