0
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 many amps does 350hp motor 480v 3 phase draw when operating?
The formula you are looking for is; Amps = HP x 746/1.73 x Volts x %eff x pf.
350 x746/1.73 x 480 x .90 x .90 = 261100/672 = 389 amps. This amperage assumes that the efficiency of the motor is at 90% and the power factor of the motor is also at 90%.
A battery of the correct voltage and at least 520mAH rating.
Because the voltage across the capacitor is initially zero, making the voltage across the resistor maximal. As the capacitor charges, the voltage across the resistor decreases, with an accompanying reduction in current. At maximum charge, the voltage across the resistor is zero, and thus there is no current.
The equation of a capacitor is ...
dv/dt = i/c
... meaning that the rate of change of voltage, in volts per second, is proportional to current, in amperes, and inversely proportional to capacitance, in farads.
Set this up into a series charging circuit, replacing the i term with (V-Vt) / R, solve the differential equation, and you get ...
Vt = VSource (1 - e-t/RC)
.... where Vt is voltage at some time t, and RC is the time constant, resistance times capacitance.
The is the DC state answer. AC circuits are a whole other issue, and require different analysis, though the fundamental equation remains the same.
What is the difference between mechanical and electrical transducers?
The mechanical transducers are the mechanical elements that are used for converting one form of energy into other form that can be measured easily.
Electrical transducers may be classified as active or passive. The active transducers generate electric current or voltage directly in response to stimulation
The equation for an inductor is ...
di/dt = v/L
... meaning that the rate of change of current in amperes per second is proportional to voltage and inversely proportional to inductance.
0.2 amperes seconds-1 times 0.1 Henry = 0.02 volts = 20 millivolts
What is the purpose of the diode in the GM AC clutch circuit?
The purpose of the diode is to prevent electricity to flow in the wrong direction in a circuit. The purpose of the diode is to prevent electricity to flow in the wrong direction in a circuit.
What are the advantages and disadvantages of electrical current?
Advantages of electric current : This is the energy source which can be easily converted into other energies like heat, mechanical, light etc very easily. Very convenient to use and environment friendly as no pollution is caused by its use at the consumer end.
Disadvantage: It can sometime prove fatal and its transmission lines used to carry current looks ugly
How many bits are in a half dollar?
Two half-dollars otherwise known as a fifty cent piece make a dollar.
no... frequency refers to the number of times something happens in a given amount of time, ie: hertz is full waves passing a point in a second.
however, since waves are additive, you can produce an "anti-wave" that in-effect cancels out a wave
What is the impulse withstand voltage?
Also known as basic insulation level (BIL): A specific insulation level, expressed in kilovolts, in accordance with which the complete system (including the line pole insulation to earth at every pole, the switchgear, the line isolators and reclosers, and the substations connected to the system, including their transformers) is designed and constructed. (NRS 039:1995)
A UTR is a Unique Tax Reference this is a 10 digit number given to you upon registering as self employed with the HMRC.
What are the Graduate entrance requirements for Stanford University?
Check the Standford University webpage.
in the same direction as the field
Will voltage drop across a capacitor?
basically a capacitor will charge to the input DC level however it will mathematically never happen since capacitors charge at a certain rate the voltage drop across a capacitor will follow the R C time constant or 63% of the applied voltage for a unit time.
AnswerIn the case of an a.c. supply, yes, there will be a voltage drop across a capacitor. In the case of an 'ideal' capacitor, this will be the product of the load current and the capacitive reactance of the capacitor.
How do you wire a 110 V DB board from a 220 V 3 phase transformer supply?
In a wye system the voltage between any two wires will always give the same amount of voltage on a three phase system. However, the voltage between any one of the phase conductors (X1, X2, X3) and the neutral (X0) will be less than the power conductors. For example, if the voltage between the power conductors of any two phases of a three wire system is 220v, then the voltage from any phase conductor to ground will be 110v. This is due to the square root of three phase power. In a wye system, the voltage between any two power conductors will always be 1.732 (which is the square root of 3) times the voltage between the neutral and any one of the power phase conductors. The phase-to-ground voltage can be found by dividing the phase-to-phase voltage by 1.732
answer from ground and any phase
FLA is the nameplate amperage rating of the motor when it is running at its designed horsepower and on the motors designed voltage. 746 watts = 1 HP. The FLA of a 1 HP motor at 240 volts would be W = amps x volts, Amps = Watts/Voltage. 746/240 = 3.1 amps full load. Overload the motor and the amps go higher, motor running at no load amps are lower than FLA
Should double insulated appliances ever be earthed?
There is no need to. The manufacturer designed the appliance for the specification of not needing a ground to be connected to it.
How do you recharge 2002 Taurus AC?
1. You need to buy a R-134a recharging tool and at least one cannister of R-134a. You can find this in any auto parts store and even Wal-Mart. These come as a package and usually cost about $20 for the tool and 19 ounce can. Additional 12 ounce cans are about $6-$9. (In some locations around the country those prices could be much higher).
2. Locate the low pressure port. It is located next to the firewall on the passenger side of the car. Looking from the front of the car, it is in the far left rear of the engine compartment. The port is in a quite akward position, so you may want to detach the cannister from the tool and make sure you can manuver the tool and get it attached securely to the port. Exercise caution when connecting and disconnecting from this port as the port's internal valve (shrader valve) could be damaged or losened in this process and begin to leak. The shrader valve is the same type of valve found in tire valve-stem's but significantly larger. If your A/C system's valves are leaking (as seen during a visual inspection), a shrader valve tightening tool of the appropriate size is required to tighten it up.
3. Start the car and turn on the A/C.
4. Determine the pressure on the system from the guage on the tool. The ideal pressure depends on the ambient temperature (the cannister may have a chart to determine the ideal pressure), but the ideal pressure is probably somewhere between 40 and 45 psi. The A/C must be engaged to get a true pressure reading. You can see if the A/C is engaged by looking at the clutch which is located directly in front of the low pressure port toward the front of the engine compartment and lower in the compartment. The cluch has three knobs on the front of it which will be spinning if the clutch is engaged. If the clutch is not engaged, the pressure will read much too high. If the pressure is significantly too low the clutch will engage and disengage every couple of seconds. As you add the refrigerant this should stop.
5. If you need to add refrigerant, look in the portion of the tool where the cannister attaches and rotate the knob counterclockwise until the puncture device is lower than the rubber seal.
6. Screw the R-134a cannister securely into the tool.
7. Rotate the knob clockwise until it is completely down. This punctures the cannister.
8. Rotate the knob counterclockwise to release the refrigerant from the cannister. You should be able to hear and feel the refrigerant leaving the can and the can will begin to get colder.
9. While watching the gauge, slowly move the can back and forth from an upright to a sideways position while the cannister is being emptied. If you empty the entire cannister, turn the cannister upside down to get as much refigerant as possible out of the cannister.
10. When the pressure reaches the desired level, rotate the knob on the tool clockwise until it is compltely down.
11. Remove the tool from the port.
12. If you emptied the cannister, remove the cannister from the tool. DO NOT PUT YOUR HAND IN FRONT OF THE OPENING OF THE CANNISTER. SOME REFRIGERANT WILL STILL BE IN THE CANNISTER AND IT IS DANGEROUSLY COLD.
13. If more refrigerant is still needed, repeat the process.
What and where is the voltage limiter on a 1989 ford f 250 4x4?
Voltage Regulator? In the alternator voltage limiter? voltage regulator...a little square box usually located on the driver side wheel well.
probably the rings are stuck or either it needs new ones or the piston is bad probably need to have the cylinder bored and the motor rebuilt it will cost about $170
What are the disadvantages of electricity?
1. Electricity can cause pollution if it is generated by fossil fuels, or nuclear energy. It can affect animal life if it is generated by hydroelectric dams or tidal power.
2. Electric devices, circuits, conduits, and transmission lines present a shock hazard to people: those who use it, those who work with it, and those who provide it. Short circuits and sparks also present a fire hazard.
3. High voltage lines are thought to cause hazards to plants, animals and people who live near them, because they produce magnetic and EMF fields.
4. People who have become dependent solely on electricity may be unable to function without it in an emergency.
A simple (and I do mean simple) formula is approximately 100 watts per amp. So, 700 watts total equals 7 amps, with 8 amps to spare on the 15 amp circuit breaker.
It's really a bit more complicated than that, considering rms voltage/current equation, but it's close enough for government use. ;)
If the vehicle is equipped with an Otto engine with a throttle plate, the negative pressure in the intake pipe is usually sufficient to operate the brake servo unit. All other engine types, including the Diesel engine, have to have a vacuum pump. In both cases, while the engine is running, the negative pressure is directed through a one way valve into both chambers of the brake servo unit. As long as the brake is not operated both chambers are connected with each other via channels. There is a movable diaphragm in between the chambers.
If the driver starts braking, the connecting rod moves left, pressing the seal of the double valve against the valve seat, thereby closing the connection between the two chambers. In accordance with the brake pedal force, more or less air at atmospheric pressure gets into the right chamber via an air cleaner (see arrows!), intensifying the brake force. The pressure in the right working chamber is bigger than in the left vacuum chamber. The diameter of the servo unit, still indicated in inches, determines the maximum braking force. For heavier vehicles one might make use of three or four chambers if there is not enough space for one sufficiently large unit. If there is a hydraulic system already present, the support work might be taken over by a substantially smaller hydraulic servo brake.
ANS2:- A valve that is actuated when the brake pedal is depressed reduces atmospheric pressure on the master cylinder side of the servo diaphragm. The higher atmospheric pressure on the other side assists the brake actuator push rod to apply force to the piston in the master cylinder. This is the most common arrangement in modern vehicles. In gasoline-powered vehicles the engine manifold vacuum is used to provide the pressure differential.
- The brake system found in diesel-powered vehicles typically uses a vacuum pump to provide the vacuum since manifold pressure in a diesel is the same as atmospheric.
- Trucks with air brakes use compressed air to push air servos (commonly called 'pancakes') located at each wheel. When air pressure is removed, a spring pulls the brake tight. A truck with air brakes will not roll until it builds up air pressure.
- Drum brakes have a servo action that results from the 'wrapping' effect of (usually) the leading shoe. That explains why the leading shoe generally has more lining than the trailing shoe. As the leading shoe engages on the surface of the drum, its geometry causes it to set tighter and transmit some force to the trailing shoe. Cars with drum brakes generally have noticeably less braking performance when stopping in reverse.
- Band brakes, similarly, benefit from the wrapping servo effect and also work poorly in reverse but you typically don't find band brakes on anything larger than a riding lawnmower.
What does 1-4W and 1-8W means for resistors and do they affect the value of the resistor?
I think you mean 1/4W and 1/8W ratings for resistors. If so, it indicates wattage (power dissipation) ratings for resistors. Basically this specification for resistors shows maximum power that can be allowed to dissipate in the resistor. Wattage does not as such affect the value of resistor (it should remain with in % tolerance value specified when operated within specified wattage).
( P=I^2 x R). or (P = I x V)
P=Power, I = Current, R= Resistance, V = Voltage Once you know the power rating, you can calcutate how much current can be passed through a resistor of specific value without causing a damage to the component or circuit. For long term reliability always it is advisable to design with a margin (for 1/4W or 250mW e.g. design so that it is always certain % less than the rated e.g. operate at 200mW or less) - Neeraj Sharma
What is the difference between current and voltage commutation?
Voltage commutation: This is possible in ac circuits...The thyristor gets turned off by reverse bias (negative half cycle) voltage applied across it. This is also called line commutation.
Current Commutation: This is possible in dc circuits ...This type of commutation makes use of auxiliary circuit which contains inductor,capacitor,diode and even a thyristor(auxiliary). This is called Forced commutation.
