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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
Circuits are used anywhere you want to have an electrical current flow. Without a circuit, you cannot have current flow. Without current flow, you cannot do any work.
What is refractory insulation?
Refractory insulation is defined as insulation for extremely high temperatures. The threshold of temperature of insulation for refractory insulation is > 815 Celsius.
How do you connect the 12 motor leads to a 3- phase supply?
The 12 lead motor is a very versatile motor and can be connected in numerous ways. It is a dual speed motor and can be wired as star delta. If you are interested, start a Discussion Page and I will see if I can help you.
What is the difference between C-60 and C-90 electrical household wiring?
This (C-60 or C-90) is a temperature ratting of wire. It is the ambient (area) temperature, in degrees celsius, that a wire can be used without de-ratting or adverse resistance characteristics becoming a problem. If I had a home in Nome, Alaska, I would have no problem wiring the attic with C-60 wire. However, I would use C-90 if the same home where in Phoenix, Arizona. Hope this helps! Terry SAFETY FIRST and ALWAYS!
Do you need to replace an overload protector if you have shorted a circuit?
Short Answer… Yes (maybe) Explanation: The reason for this is that there has been an overload of the materials or circuits. This has caused overheating of the metals and undue stress or fatigue. This would include the circuit protection components (circuit breaker). As there has been current and heat in excess of the design loads, it is reasonable to assume that the properties of the breaker parts have changed and failure is more likely to occur, preventing the device from functioning properly. The reality is: The change is minimal and that although the manufacturer recommends replacement, failure of the device may not be imminent. It is up to you to determine if the function of the device has been really compromised. Most breakers can withstand multiple trips without a risk of failure. However, it is always best to remember that the cost of a breaker (about 5 to 10 dollars) is not worth the risk that you may put on the house. My personal feeling is: If you have tripped the breaker because you have been stupid and plugged the mixer into the same outlet as the toaster (I can say stupid, because I can claim stupid). Chances are that you can reset and continue on. If however, you either can not determine the cause of the trip or you have had a damaged wire or experienced extended overheating (running a large amp motor for some time), I will always replace the breaker. As always!!! When in doubt call a qualified electrician to assist you. Remember that electrical failure is one of the largest causes' of house fires. Hope this helps! Terry SAFETY FIRST and ALWAYS!
What time-current characteristics for a 40A type B circuit breaker?
200a for rcbos to bs en 61009-1 for bs88-2.2 and bs 88-6 400a at 0.1 sec
What can be used to clean circuit boards when you are finished soldering?
Defluxer spray, compressed air, or water.
Where can someone purchase Transformer figurines?
Transformer figurines can be purchased at many retailers. Online Transformer figurines can be purchased at Amazon, Toys 'R' Us, eBay, Craigslist, Toy Wiz and others. In local markets, Transformer figurines can be purchased at Walmart, K-Mart, Toys 'R' Us, Target and comic book stores.
What is the cheapest electric supply cost single phase or 3 phase?
The cheapest service to construct is a single phase service. A three phase service requires more equipment and materials to complete a service.
The transformer primary winding is connected to the alternating current supply. This causes a varying current in the primary winding, which creates a varying magnetic field in the transformer core. Because the primary voltage is alternating, the flux is also alternating - expanding and contracting, and changing polarity in time with the supply.
This alternating core flux 'cuts' the secondary winding/s of the transformer, and induces a voltage in the secondary coil/s. As long as there is a magnetic field that is moving, and a conductor for it to move across, it will induce a voltage in the conductor. While the actual induced voltage depends on the amount of flux, the amount of conductor material and the rate of change of the flux, the actual voltage can be calculated from:
Vsec = ((Vprim * Nsec) / Nprim)
where V = voltage, N = number of turns of wire in the coil, prim = primary and sec = secondary.
Transformers don't work on DC - they give a brief pulse out at switch-on and switch-off, because that's the only times the current is changing and the flux is moving. If you have to transform DC, you use a switching circuit that 'chops' the DC into a series of pulses that simulate AC as far as the 'moving flux' requirements of the transformer are concerned.
How much voltage in three phase line in electric in India. each phase rating 230V?
If the phase voltage is 230 V, then (providing you are describing a three-phase, four-wire, system), then the line voltage will be 1.732 larger -i.e. 400 V.
it has a transducer in it, but is not one itself
What is the difference between a thermal motor protector and current-type motor protector?
thermal motor protector is temperature; current type is current.
Why do you connect a capacitor panel to the load?
Capacitors are sometimes connected in parallel to inductive loads to improve the power factor, raising the voltage of the source AC.
Power factor is the ratio of apparent power over true power. It is 1, if the load is purely resistive, such as in a toaster, but it is less than 1 if the load is reactive, such as in a motor. This is because current is not in phase with voltage in that case. Inductive loads cause the current to lag voltage, and capacitive loads cause the current to lead voltage. Placing capacitors across an inductive load tends to compensate for the lagging power factor.
Specifically, power factor is the cosine of the phase angle between voltage and current. In an ideal situation, with perfect sources, conductors, and reactive loads, the phase angle would be plus (capacitive) or minus (inductive) 90 degrees, and the power factor would be zero. This means that a conventional watt meter would register zero but, in reality, energy is still being supplied, and that has to be accounted for.
In practical terms, since conductors have impedance, a poor power factor degrades voltage so, adding capacitors raises voltage.
What is the advantage of a Star Delta Motor Starter?
The inrush current to the starting motor is lower due to the the motor coils being in series across the line creating a higher impeadence. When the starter connects to delta connection the motor is already turning and it does not have to go through the locked rotor phase. This system is being phased out now with the use of electronic soft starts and by-pass contactors.
To start a motor direct on line (DOL) in delta requires approximately 6 to 8 times the full load current of the motor and delivers full torque. Delta places 415v across each of the windings on the motor. A Star-Delta starter starts the motor in Star which places 240v across each winding on the motor. This results in a lower starting current and also a lower starting torque.
If your appliance or motor is asking for 208 volt, it usually means that it also wants 3 phase. If you measure the voltage between the hots on a 3 phase feed, you will find that it is somewhere around 208v. As long as you connect it to the 2 or 3 hots that you measured, then you will be fine. Make sure you ground, and no neutral should be present.
Effects of connecting poor contact in electrical circuits?
An effect of connecting a poor contact in an electrical circuit could be intermittent current flow.
First find the ratio of the transformer. 6600/220 volts. Second find the secondary current, I = W/E, 99000/220. Third divide the secondary current by the transformer ratio. The answer will be the primary current. To check your answer (W (or VA) = V x A) multiply the primary current times the primary voltage and the secondary current times the secondary voltage and they should both equal the transformer's kVA.
