Electrical Engineering

the cosine of the angle between voltage and current of generator is called power factor (pf) of generator.

It depends on the signal you are trying to receive.

For instance, the AM frequency band lies around 500KHz to 1700kHz. Lets say you have a tuned amplifier such that the resonant frequency was set roughly in the middle of that band at 1000kHz (1MHz). AM radio stations typically space out their broadcasts 9-10kHz.

So if Q=f_resonant/f_bandwidth

the Q of a tuned amplifier with a bandwidth of 10kHz (which would be decent, maybe a little spill over), would be:

Q=1Mhz/10kHz

Q=100

The higher the Q, the greater the selectivity. Too high be a bad thing too.

A Conventional fly back converter is revamped using an intercell

transformer,unlike a normal transformer Construction of

inter cell transformer varies by usage of coupled inductors

where compactness , overall efficiency and cost effectiveness

are dramatically improved

One application is to determine the neutral current in an unbalanced wye (star) connected load.

In a typical residential situation there is 220 to 240 volts between the two hot wires that are typically red and black and 110 to 120 volts between neutral and either black or red. The voltage between neutral and earth should be zero.

Norton’s Theorem states that any linear electrical network with voltage and current sources and resistances can be simplified to a single current source in parallel with a single resistor. To apply Norton’s Theorem, first, identify the portion of the circuit you want to analyze and remove the load resistor. Then, calculate the Norton equivalent current (I_N) by finding the short-circuit current across the terminals and the Norton equivalent resistance (R_N) by turning off all independent sources and calculating the equivalent resistance seen from the terminals. Finally, replace the original circuit with the Norton equivalent circuit for analysis.

They are usually built on the ground and then they use a pulley to lift into position

The maximum rating or a VCB is 32 KV.The maximum curent rating is up to 3000 A.

To my knowledge no transformer is air conditioned. Some transformers have fans mounted on them, however, for uprating purposes. I don't believe this is an effective cooling mechanism for dry type transformers either (fans are usually used on oil filled transformers).

Gives us Copper loss

A very popular idiom, or phrase, that stands for "no excuses". It was mostly used by parents for telling their children to complete a task without any form of delay.

I, too, was quite intrigued by my tower fan at home. Inside it, there's a cylinder/drum with vanes on it. So it looks like it should work like the reverse of a centrifugal pump or impeller mechanism:

What amazes me is this:

An impeller will propel air out from the inside of the drum to the outer circumference of the drum. However, my tower fan does not do this. It actually creates suction on it's slatted sides, and pushes out air from the output slats on the other side. I can't understand how one side sucks and the other blows when it is just a rotating drum with vanes. The vanes should move air either all outward of the drum or all inward. How can the same vanes cause suction on one side and blowing on the other?

My theory is the shape of the casing plays a big role. On the suction sides, the drum is exposed to the static outside air. Then the casing narrows around the drum surface, sealing that half of the rotating drum. Finally the narrowed casing opens to the output vent, where the air blows out of. The casing once more hugs the drum and opens back out into the suction side.

What I think is happening is this:

The air speed is slow on the suction side, so when the impeller spins, the faster moving air in the impeller vanes is at a lower pressure than the static air (Bernoulli's Principle). Thus you get suction as static air is sucked into the fast moving impeller.

Then the casing narrows and hugs the impeller - no more air can be sucked in, but the air is being flung outward by 'centrifugal force' i.e. its inertia. The casing prevents this air from being flung out until it hits the output vanes - then it shoots out and this is the fan blowing. The casing immediately hugs the drum again to seal off this output vane, before opening up to the suction half of the drum.

From what I've read the air is pulled into the core of the cylinder and forced out the top and or bottom into the housing the out the vents.

I don't understand why the air isn't sucked right back into the core rather than out the vents

i.e. instead of converting kinetic energy to static pressure (like an impeller pump), it converts the static pressure of stationary air to kinetic energy.

I'm sure I don't have a complete understanding of what's going on, and I'd like to ask a fluids professor, but this'll start you off anyway. I'll check back here in case anyone came up with brighter ideas, and post a link if you end up finding out the answer elsewhere.

take the full load current

1.732*415*I*0.85*efficiency=115*1000 => I?

Depending on the value of the full load current and designed and ambient temperatures of the selected category of the cables, and voltage drop per unit length, you can determine the cable size

5 hp moto 1500 rpm 3 phase winding calculation

Hi,

RMS is voltage X .707 and the power is voltage X current.

Hope that helps,

Cubby

a contactor is generally looks like a small box connected to an electric circuit. it is what controls electricity flow to a motor. in the middle is normally a way to push in the contactor to manually check to see if either the motor works or if you have electricity.

The size of the wire is the main factor when dealing with voltage drop. The idea is to maintain the voltage and a specific amperage at the load end of the circuit.

15

The LM555 is a highly stable device for generating accurate time delays or oscillation. Additional terminals are provided for triggering or resetting if desired. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor. For astable operation as an oscillator,

the free running frequency and duty cycle are accurately controlled with two external resistors and one capacitor. The circuit may be triggered and reset on falling waveforms, and the output circuit can source or sink up to 200mA or drive TTL circuits.

There is little point in desoldering one since they are very cheap to buy since the chip is nearly thirty years old.

NE/SA/SE555/SE555C Timer circuits are all over the net.

Both

An 800W load refers to an electrical device or system that consumes 800 watts of power during operation. This measurement indicates the rate at which energy is used, and it can be important for determining the appropriate power supply or circuit capacity. For example, if multiple devices are connected to the same circuit, their combined wattage should not exceed the circuit's rating to avoid overload.

no

Everything follows ohms law. that's why it's called a law. There is no get out of jail free card when it comes to ohm's law.

The full law even takes into effect radiative power, or power transferred through antennas.

A constant parameter is one that does not vary over time, or varies so slowly, or within a very small, allowable range, that it can be used as a constant. One such parameter is the average temperature of the universe, which is 3 Kelvin. We theorize that over time it will gradually decrease with the expansion of the universe, but in practical terms, in a period of billions of years, it is held as a constant.

Diurnal light and dark cycles (day time and night time) is an example of a time varying parameter. The intensity of solar radiation, measured in a specific location, varies continuously during each day, and the length of each day varies continously through the year.

Yes-rats, mice and other animals use weeds for their nest and also like to chew on wiring and insulation found at electrical sites. Their damage cost more than clearing weeds.