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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 do you determine ampere hour for two 12v dc batteries?
To determine the ampere-hour rating of a battery, read the label on the battery or consult the manufacturer's specifications for the battery. That is the best way. It is also possible to measure it, but you will be using up capacity on the battery and, if it is non-rechargeable, that will exhaust the battery.
First, decide what the discharged state is. This could be a certain voltage under load, the inability to provide a certain current, or (best in the case of a lead-acid battery) the specific gravity of the electrolyte. In a typical 12V lead-acid battery, such as in an automobile, the discharged voltage is around 10.5 volts under load. {This writer does not know the specific gravities involved - someone else, please feel free to refine this answer.}
WARNING: batteries generally emit explosive gases when being charged or discharged. Take necessary precautions, and vent the battery as needed.
Starting with a fully charged battery, draw a load of some current, and find the current that will discharge the battery in eight hours. Start low, unless you have some idea of the projected rating. If the projected rating is, for instance 80 ampere-hours, draw 10 amperes.
Recharge and repeat as needed to obtain a statistically consistent result.
When you have the amount of current, say 15 amperes, that will discharge the battery in eight hours, multiply that number by 8, in this example giving 120 ampere-hours.
The reason for multiplying by eight is that is the convention for reporting a battery's capacity. You say "120 ampere-hours at an 8 hour rate", which simply means 15 amperes for 8 hours. If you were to actually pull 120 amperes, the battery would discharge in less than one hour, and if you were to pull 1.5 amperes, the battery would discharge in greater than 80 hours.
How is solar power returned to the grid?
Solar power is provided to the grid whenever the available solar power exceeds local consumption. Energy produced by small arrays helps satisfy the energy needs of neighborhoods -- and this locally produced and consumed energy relieves the grid from having to transport the energy there in the first place.
4.5 volts in series; 1.5 volts in parallel.
Can there be 600 volt single phase power?
Yes there is single phase for 600 volts. It is used for lighting. You need a transformer which gives you 600 volts plus a neutral. The voltage for the one phase to neutral is 347.
Are a tapped transformer and a step-down transformer the same?
Transformers can be used in either step-up mode or step down mode, they are just as efficent connected either way. Most large transformers have percentage "taps" to allow voltage corrections up or down by about 15%.
Insulation tests inserts high voltage DC across what ever is being tested. This voltage could be higher that the diodes peak reverse voltage. The diode might bridge across the PRV rating using a voltage higher than its normal operating voltage and destroy the diode. All variable frequency drives and soft starts will have a label on them warning against preforming this type of test with this type of equipment in the circuit. Disconnect the load from the drives when meggering a downstream load.
How you can connect three single phase transformers as a three phase transformer Y to Y?
You can not unless the installation is a motor and cost is not important. 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.
Why in slip test the machine voltage reduced?
The low slip test is used to determine the D and Q axis impedance of salient pole machines. The machine terminals are short circuited, each phase voltage and current are measured. Since the terminals are short circuited, machine voltage must be reduced to prevent excessive output currents that would damage the machine.
How do utility companies dispose of old transformers?
Those built in a useful capacity rating are reconditioned, tested, and
kept in stock to replace others. Those that have been totally destroyed
by lightning, or are of such small capacity that they no longer have great
value in our modern power-hungry neighborhoods, are sold by weight as
scrap metal. Their value is not insignificant, since a large part of the weight
of a utility transformer is the copper windings, and the price of copper has
gone through the roof lately.
I had a college summer job in the "transformer room" of the local utility
in my home town, in the early 1960s. I took a little 5 KVA transformer
that had been hit by lightning, replaced, and brought in for disposal.
I disposed of what was left of the burned oil, steam-cleaned the core,
high-voltage tested it and confirmed that the windings were fine, then
reassembled it, painted it with a new coat of dark blue and my ham-radio
call-sign, and took it home in return for a $3 payment to the company.
I still have it and have never used it yet. But if I ever get around to it,
I can either build myself a legal-limit ham radio power amplifier now that
I have the most expensive component, or just surrender, admit that I'll
never use it, sell the 50 pounds of heavy copper wire in it, and buy something
nice for my wife.
What is the role of resistors in household appliances?
Probably the most common resistor in a household appliance is the resistive heating element. They appear in an electrical stove or range. The standard electric range and its oven have resistive heating elements in them. They're just "oversized" resistors that get really hot when we run current through them. Toasters have resistive heating elements, too. Most of the use nichrome in the form of wire or in little flat strips. Some have quartz heating elements, which have that resistive heating element inside quartz or fused silica glass. Coffee makers have resistive heating elements. Toaster ovens, too. Hair dryers and straightners? Yup. Anything that plugs in and is designed to get hot probably has a resistive heating element in it. There are actual resistors, like the electronic components, in all the electronic equipment in the house. All of it. They may be discreet components, or may be part of an integrated circuit. But they're there.
You press z to transform in esf and you need a pecific power level to transform for example: Goku Transform Power Level ssj=2,000,000 ssj2 (you have to be ssj to transform into this) = 7,000,000 or 6,000,000 ssj3 (ssj2 reccomended) = 15,000,000 and if you want to go back to normal form just press x but when you press x you dont have to press it multiple times just press it once and you will instantly descend to normal form cause you cant descend to the other transformations why?I dont know the ssj2 and ssj3 you can transform into them if you install the coronabytes.net_ ecx rc2.exe
get it at filefront.com
I cant give the full link because i didnt copy it and paste it where the "filefront.com" is so sorry
To solve for resistors in parallel take the inverse of the sum of the inverses of all the resistors: 1/((1/r1) + (1/r2) + (1/r3)...)
[Google this. It is a lot easier to understand when the proper notation can be drawn.] SO: Rt = 1/((1/70) + (1/30)) = 21ohms
What is Primary HO2S No 1 Heater System Electrical on 2000 Honda Accord?
This is the "Primary Heated Oxygen Sensor," which *I believe* controls the air/fuel mixture.
Does resistance use amps or voltage?
Resistance doesn't "use" either. Resistance is the division of voltage by current. It can be though of as a measure of how hard it is to push electrons through a substance.
Why motor protection circuit breaker is not used in star delta starter?
please you give me reply to answer.
What happens to the flow of electricity in an incomplete circuit?
It stops flowing. An analogy to this is the kitchen faucet ... water is always "at the ready" behind the valve, ready to flow when it is enabled. Same is true in an electrical circuit - once the circuit is broken (valve closed in above analogy) the flow of electrons ceases.
If there is a light bulb which is not on it is a open circuit. If the light bulb is still on it is parallel circuit which has lot of wires causes some of the lights to go on and some to go of.
There's no reason for the capacitor to heat up, because it's only storing energy,
not dissipating it. When you discharge the capacitor, the energy flows out and
through the external circuit, and that's where it dissipates. If anything is going to
melt or explode, it's going to be something outside of the capacitor, through which
you try to jam the energy.
Which brings us to the 1-ohm resistor . . .
You have said that you have a "450V" capacitor. The rating marked on a capacitor
isn't the voltage across it when it's charged ... that can be whatever you make it.
The marking is the maximum that the capacitor can hold without arcing across
between the plates ... the number is called the "maximum working voltage".
You can try to charge a capacitor to whatever voltage you want, but it won't
hold any more than the number marked on it.
In order to discuss the fate of that 1-ohm resistor, we have to know what the
initial charge is on the capacitor. The only number given in the question is 450V,
and even though that's more likely the "max working voltage" of the capacitor,
let's assume for the moment that the capacitor is actually charged up to 450 volts DC.
The charging is complete, the staff retreats behind their bullet-proof plexiglass
bunker, puts on their dark glasses, and prepares to push the button that will
remotely close the circuit and discharge the capacitor through the 1-ohm
resistor. The button is pushed, and here's what the high-speed camera reveals
after the smoke clears and the fire units have departed:
As the energy drains from the capacitor, the voltage on it steadily dwindles.
How fast it dwindles depends on the resistance of the external circuit, and on
the "capacitance" of the capacitor (which tells us how much energy it takes to
charge it up to any given voltage).
What we do know about this circuit is that the capacitor is charged initially to
450 volts, and that it discharges through 1 ohm. This is enough for us to
calculate the initial current at the instant the switch is closed ...
I = (450 volts)/(1 ohm) = 450 Amps.
We can also calculate the power dissipated by the resistor at that instant:
P = I2 R = (450)2 x 1 = 202.5 kilowatts ... roughly the power that would be
demanded of a car battery if it had to start 85 cars all at the same time!
Regardless of the capacitance, and how quickly the charge on the capacitor
dwindles down from 450 volts, it's likely that this initial surge through the
1-ohm resistor causes it to self-destruct like a pellet of plutonium on the
tower at White Sands.
To answer the question:
Your capacitor is safe from harm. But if you're going to discharge it through 1 ohm,
then please wear gloves, safety glasses, and a kevlar apron.
When would you use a delta versus wye secondary three phase transformer?
If the secondary system is ungrounded, or the secondary system is phase shifted +/- 30 degrees from the primary. I've even seen where the secondary system was phase shifted 150 degrees, so a special transformer was installed. There might be other reasons as well - cost, matches other equipment so a spare is not required, "it's what we've always used", etc.
What is Voltage drop compensation?
A; The best way to describe is this way the load requires 10 volts but due to wiring and bad connections it gets to be 9v 1 volt is lost on IR drop so to compensate the input voltage needs to be boost up to 11 volts to insure 10 volts across the load
Why some countries use low voltage but others use high voltage?
You must understand that with higher Voltage you will get lower amounts of current therefore some countries use lower household current applications therefore without diminishing circuit efficiency it is more ideal to up the Voltage
AnswerThe main advantage of using a higher value of a residential voltage is that it enables the use of higher loads.For example, the maximum load for a North American 'receptacle' is 15 x 120 = 1800 W.
The maximum load for a UK 'socket outlet' is 13 x 230 = 2990 W.
Typically, therefore, most UK households use kettles, electric heaters, etc., which are rated around 3 kW -practically double that of the American equivalent.
STATE the transmission sequence between power station and various consumers of electrical energy?
i don't really care to f**k what the answer is anymore, I've searched an searched but to no avail, if you are reading this then you are also screwed just like the person who is typing this message behind your computer screen on the other side where everything is back to front or flipped, this is not a joke the world is about to end you don't need to find out this answer, because at the end of it all it all makes no sense, so stop what your doing right now and go stare into a mirror for 6minutes (don't even blink or look away for a sec.), then turn around and wait for 6sec., then turn back and face the mirror an you'll see the real truth of this world, but remember do this in the night with all the lights off in your house, never and i repeat never look into a mirror during the day...i'll leave it there for now but if followed correctly and you'll see the truth of this world, on the other side it will grant you one wish (choose carefully and show no fear), you'll understand what is true power when they bring you back.........
3 phase 480 volt motor that continually trips the heaters?
By the phrase "trips the heaters" I am assuming that you meant the Overloads. There are 3 possible answers: 1) The Overloads are not the correct size or are in a high ambient temperature envornment. Most manufacturers have sizing charts that take these into account. 2) The motor is bad or in the process of going bad. 3) The motor is overloaded. If you are running a 7 1/2 HP motor on a load that requires 10 HP then the motor will draw too much amperage and trip the overloads.
Whats the permissible voltage drop in a 240V system?
You shouldn't really have much voltage "drop". If you do, it usually means that there is a poor connection somewhere along your service line or inside wiring. Any significant amount of voltage drop can mean that you are at risk of a fire. On the other hand, line voltage into a house may not actually be 240 VAC. Measure the ACTUAL voltage with everything turned off, then see where it goes when you start turning things back on. The difference between the supplied voltage and the load voltage is the voltage "drop".
