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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
Where can one purchase a stair stepper?
A stair stepper can be purchased at stores such as Sears, Amazon, Brookestone, and Wal-Mart. It should also be noted that the stores mentioned are a few places that a stepper can be purchased.
To design a second order low pass filter?
Although there are many filter types and ways to implement them, here's an active low-pass filter that's greatly simplified if R1=R2 and the op amp stage is a unity gain follower (RB=short and RA=open). Designing a 2-pole Butterworth filter requires just a few steps. 1. Choose a cutoff frequency fo (Hz). As an example, select fo=10 kHz to reduce a noise signal at 50 kHz and pass your desired signals below 5 kHz. 2. Pick a convenient cap value C2 between 100pF and 0.1 uF. Suppose you've got plenty of 1000pF caps in stock, select this value for C2. 3. Make C1 = 2 x C2 C1 = 2 · C2 = 2000pF 4. Calculate R1 = R2 = 0.707 / (2 · π · fo · C2) R1 = R2 = 0.707 / (2 · π · 10kHz · 1000pF) = 11.2 K ohms ......Rajiv......(scet)
What electronic part is used to close a circuit when current is passed through it?
Sounds like a relay to me.
Are dc voltage fuses different to ac voltage fuses?
AC alternates - so the current naturally passes through zero twice very cycle. Interruption in an AC Circuit breaker takes place at one of those natural current zeros.
There is arcing during the course of interruption - dielectric strength builds up gradually as the breaker contacts physically open, and until the contacts have opened sufficiently, conduction will re-establish after the initial currents zeros. But once the contacts are open sufficiently to provide enough dielectric strength, the arc will be extinguished. The breaker mechanism may include provides to accelerate arc extinction - typical scheme include arrangements that extend and cool the arc.
DC does not alternate, so there are no natural current zeros. That implies two things. First, the physical opening of the breaker must be faster and physically greater to create sufficient dielectric withstand to extinguish the arc. That is usually what is done with smaller breaker.
But for breakers with larger electrical ratings, it may be necessary to include a provision to force an artificial current zero. One approach is to include a capacitor that is charged by the normal DC voltage, and that is inserted into the circuit as the breaker opens to oppose the normal voltage to force the current to zero.
How many volts is the voltage required to push eleven amperes through a 20-ohm resistance?
voltage is equal to resistance multiplyed by current. you have the 2 pieces of info, just multiply
How do you calculate the resistance in a circuit in which a 9-volt battery produces 3 amperes?
Where V=stands for voltage, I=stands for current and R=stands for resistance. voltage=current multiplied by resistance so, by transposition, resistance=voltage divided by current. or R=V/I, R=9/3 The resistance is 3 ohms.
as by ohm's law, v=ir
r = v/i
therefore the resistance is 9/3=3 ohms
.Use Ohm's law to find the applied voltage if the current is 5 amperes and the resistance is 3 Ohms?
ohms law states V = I*R; V = (.005)(1000) = 5volts.
If volts increase amps will decrease?
Not necessarily. In a simple circuit V=IR, so if the resistance in a circuit remains constant, then voltage and current are directly proportional, so an increase in one will increase the other. If you were to change resistance and keep voltage constant, then the current would be inversely proportional to resistance, so as resistance went up, current would go down.
What allows the current to enter the electronromagnet in an electric motor?
The resistor allows current to enter the electromagnet in an electric motor. The resistor regulates the amount of current that enters the electric motor.
What are the responsibilities of a Mechanical Maintenance Engineer?
as mechanical maintenance engineer following responsibility
1.doing preventive maintenance and keep machine condition good as possible.
2.finding machine requirement in running condition
3.attend machine breakdown and find the route course of same
4.check machine all spare parts and constable items stock as required.
What is the diffence between a motor run capacitor and a lighting capacitor?
The main difference is that lighting caps are required to contain a bleed resistor in parallel across the cap s terminals to drain the high voltage contained in the capacitor to safe levels (usually within a minute or so) after the equipment is switched off. Motor run caps don't require bleed resistors due to them being constantly connected to the motor windings which act like a resistor to drain the capacitor after use.
How do you put definite purpose contactor?
Depends on where you want to put it! Assuming, that you're asking ~how you'd "install" a Definite purpose contactor.
What is the importance of speed control of induction motors?
Speed control of any kind of motor is important because it enable the user of the motor to restrain the motor speed to the needed or required speed to accomplish a specific task. omatycoon@gmail.com
In order to determine power from volts and amps, we need to know the power factor and efficiency, but the question did not provide that information, so I will make an educated guess that the efficiency is 0.95 and the power factor is 0.92. The actual motor nameplate ratings will have to factor into the real calculations.
460 V times 120 A is 55.2 KVA. The question did not say, but it is assumed that the 120 A is per phase, so divide by 1.732 (square root of 3) to get winding power of 31.9 KVA, and then multiply by 3 to get total winding power of 95.6 KVA. Multiply by 0.92 and 0.95 to get power in watts of 83.6 KW.
If you want to know kilowatt-hours for 30 days, multiply by 30 and 24 to get 60.2 mega watt-hours.
What metal is normally used for wires in electric circuits?
Gold or silicon may be the metal most popular for use in electronic circuits. Gold because it does not corrode in the atmosphere and silicon because it is used to make semi-conductors.
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A lot of gold is used for fine wires and contacts... Silver and copper quickly oxidise (also called "tarnish") if exposed to the atmosphere so are not used as much despite their very good conductivity which is almost as good as gold.
A capacitor is a device used in most electronic devices to store electric charge in order to keep the system functioning. If for example a television was in used for a few hours and then shot down, if aTechnical has to perform some hardware services on the device due to some malfunctions, He needs to handle the capacitor with care or have it discharged before touching it with his bare hands, otherwise he stands the risk of electric shock and consequently death.
How can a 240V single phase split ac work in the US which has a 120V 2 phase system?
Note
"2-phase" to describe US residential service is depricated nomenclature. US residential service is single phase because the two hot supply phases have 0 degrees of separation between their phases: therefore they are in phase.
The two phases are pulled from 2 out of 3 corners on a 240v (line-to-line) 3-phase delta-primary transformer, usually out in the street. (Sometimes at your house if it's a big one). Basically all power is generated and transmitted as 3-phase. Usually around 415V 3-phase comes into the primary of the 3-phase transformer. (It could be delta- or wye-connected.) The secondary windings for all three phases will each have a center-tapped connection, and that's grounded at the panel. This is the neutral wire. All circuits in houses return via the "common" or "neutral" wire to this point, which happens to be grounded at the panel. Note: no neutral wires should be grounded anywhere else. The two "corners" are 240v relative to each other, and 120v each to the center tap. Each 240V circuit really is two hot wires plus a neutral, which is why it's often wrongly called two-phase when in fact it's just single-phase. For each 120V circuit in the house you're going to use one hot wire and one neutral wire. The neutral wire provides a return path for currents back to the generating station. In some installations, such as apartment blocks, the third leg of power would be at 208V with respect to the center tap.
Another answer
Just what does "220v single-phase split ac in the US which has a 110v 2-phase system" mean?
The vast majority of electricity in the US is delivered as single phase or three phase. The only areas in the US that use 2-phase [for industrial and commercial purposes] are Philadelphia/South Jersey [where it is being phased out-no joke intended] and somewhere out west...
It was one of the early poly-phase options pursued because of the natural magnetic differential between phases [makes motors spin without a capacitor]
Most residences receive 220-240 volt single phase electricity with a grounded center-tapped neutral, the purpose being to limit voltage to ground to less than 150 volts from either "hot".
If you can Chang winding 50hz to 60hz?
If you have the motor rewound you could possibly have it changed. You can run some 50 hz motors on a 60 hz system but there are no guarantees. The motor will run faster and there is a chance it will overheat. There is no way to change the field connections of a motor to accomplish this. Best bet is to just purchase the correct motor.
Can you connect a 3 phase motor to a 1 phase supply?
Single phase to three phase
The physical internal windings between single phase and three phase motors makes this an impossibility That being said money can make anything happen. Depending on the amount of money you want to spend to make this happen there is a device on the market called a VFD ( Variable Frequency Drive). On the three phase input terminals you apply your single phase voltage. On the output terminals you connect your three phase motor. When run in this configuration there is an internal switch that has to be changed to let the VFD know that it should be looking for only two lines on the input to be hot. Other wise the VFD thinks that there is a line loss on the three phase input terminals and the unit will not start.
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Some 3 phase motor speed controllers can be run off a single phase supply, this caused us a problem at work when a new speed control was fitted to some laundry equipment, as we then had to rewire the supply to bring in a nuetral, so i suggest a speed controller is probably the solution.
What can high voltage do to you?
The really dangerous thing is how many electrons per second travel in the human body and this is the current. So the current is the "dangerous" part, and, as i remember correctly,
if you stick(similar to electrolysis where your blood acts as an electrolyte ,here current is directly set up in the electrolyte) 2 electrode needles in your body, a 9V battery is sufficient to electrocute you (because the resistance of the electrolyte in the blood is really low and so the current is high), but if you don't stick(just touching the too needles with hand etc etc..) anything in your body but only touch two wires, the tissue resistance is high enough and the 9V battery is harmless.
Do Power is directly proportional to resistance or inversely proportional to resistance?
It is both proportional and inversely propertional to resistance however I am not exactly sure why which is why I am searching Google ATM for answers.
