Electrical Engineering

resistor grids were used in DC MOTORS during dynamic braking. in this method of braking a resistance ( variable) is connected across armature winding so as to dissipiate the energy. the energy thus dissipiated is used for braking of motors.

Of course it has! it can also produce up to 7500 revs. the 3AU came up first before the 4AG, they are both use for Levin and trueno coupe version of Toyota, they also both use timing belt for their Over Head Cam, the only difference is that the 3AU only have single over head cam (SOHC) while the 4AG have double over head cam (DOHC) by the way, they also have a different power output becasue 3AU only have 8 valve while 4AG have 16, anyway, perfectly uned 3AU nowadays can still kick some butt.

A forward biased diode is not a complete short. Depending on it's design, it will have some forward voltage drop. Silicon diodes normally hafe a drop around .7 V, germanium have a drop around .2V. Some of the newer Schottky diodes fall in between. Selenium diodes have a greater FWD drop.

Applying turn ratio to a transformer is to step up or step down voltage in an AC system. If you apply a 120V/60Hz (US outlet) to a 3:1 tranformer, you will output a 40V/60Hz signal as the primary side (input) has 3 times the turns (windings) as the secondary (output). From the law of conservation of energy, the secondary side (40V) will now have 3 times the current than the input.

120V x 3A = 360 Watts

40V x 9A = 360 Watts

Example: 40V AC Motor with 9A has more torque than a 120V AC Motor with 3 Amps as current is porportional to torque. Voltage is porportional to speed.

First off, I'm going to have to quore Robert here: (LIFE SAFETY WARNING! [disclaimer] Electricity is dangerous! You can be injured or killed! Improper installations can cause fire, injury and death! Should you be doing this yourself?) This is one of those questions - if you know this little, you shouldn't be doing what you are planning... No disrespect intended, but this is SO basic that it suggests you have not studied the subject at all! There are many good reference books and course books to study from. Unless you have 208V 3 phase power, you cannot make this work. You cannot power a 208V motor off a 120V supply. Since it is 208V, it is likely that it is a 3 phase motor. That means it has 3 hots. Check the specification plate on the motor, it should say how to wire it. With 208V 3 phase you should be able to get 120 from 1 hot phase to neutral. This means you need 5 feed wires (3 hots, a neutral, and ground) from your panel to your little light/motor contraption. Please buy a book and read up on this. It sounds like you don't know much about your system and ignorance is fatal (and not necessairly fatal to you) with electricity.

An inductor looks like a piece of wire to DC. It will thus look like a resistor, and inductor properties do not apply.

i do not know about the breaking system but bullet trains work by maglev, or magnetic levitation, to propel

yes you probably could

Did you measure the currents?

Look also to the voltage (peaks). Thyristors can damage due to voltage peaks form the grid (in your case the generator). Are there more loads connected to the generator which can cause voltage peaks?

Dear Sir,

One of the possible reasons for voltage over-shoot is your Generator which is not rated much beyond your load. Please note that any AC Motor will draw heavy current at start-up depending upon load characteristics which may even be four times than your rated current. Under such circumstances, your generator will be overloaded and frequency and voltage may take a momentary dip. ( Yes, Dispite using a soft starter!). This will create a complex situation which is will make the governor of Generator feed more fuel for increasing the speed and exitation of Alternator to inject more current to increase voltage.

This may make the voltage to overshoot momentorily, which might probably destroy your thyristors. If more details are provided, like when do thyristors fail, at startup or while running, may help analyse this better.

Hope this helps.

Mahesh Vyas.

mail@archana.co.in

There may also be a possible ground fault within the motor or the wires to the motor. The ground fault occurs when the motor is conducting through an alternate path than the phase wires. Some systems use a current transformer around all the phase wires to determine if there is a ground fault as it will detect any time the currents don't sum to zero in a three phase system.

There is two types. One is for R-22 and the other is for R-134A or R-410A. You must perform superheat and subcool, measure ambient temperature and wet bulb.

You will need a reverse rotation cam and lifters, reverse rotation front a rear main seals, reverse rotation distributor, and a reverse rotation starter.

Go to www.Slowhero.com. It Shows all the paths on all difficultieis for all games between gh1, gh80s, gh2, gh3, ghA. and their all optimal

The amperage flowing through a wire is directly related to the load placed on the circuit, and has nothing to do with wire size, except that a larger wire will carry more amperage. Increasing wire size will not lower amperage but will allow the circuit to carry more amperage if the breaker is also increased in size.

No. Ohm's law tells us that V = IR. For a given load, R is constant, and thus the only way to reduce current is to increase voltage.

The room fuse in my '99 626 protects _ignition-off_ function of the power door locks, headlights, and some other functions, IIRC including all operation of the radio. For example, if the Room fuse is blown, my power locks work, but only with the ignition switch on. Doc

the drier is located on the driver side next to the washer solvent bottle, you will have to remove the plastic fender well in order to access it.

An un-interruptable power supply (UPS) - provides power to equipment if the mains supply fails. It allows (for example) computer-users to finish the work they're doing, and close down the computer properly.

Yes. The resistance does depend on frequency. The reason is 'skin effect'.

When an alternating current is passed through a conductor only a small portion of the conductor, usually called the skin depth carries the current. The value of skin depth is inversely proportional to frequency. As the frequency is increased, the skin depth decreases. But the value of ac resistance is directly proportional to frequency, or in other words, inversely proportional to skin depth. Thus, at higher frequencies, ac resistance is higher. This is the reason why we multiply the dc resistance by an empirical value 1.2 or 1.3 to calculate its ac equivalent.

The resistance measured across the excitation terminals of the load cell, when the output terminals are open.

A toaster uses a pair of rigid insulating sheets with nichrome wire winding back and forth across the sheet, one on each side of each slot. The nichrome wire on these sheets form very high wattage air cooled resistors, when electricity flows through these wires they glow red hot (see image above) producing the heat that toasts the bread from both sides.

Yes it can, if there is an internal short circuit.

For electrical purposes the formula for calculating the circular-mil area of a circular wire is very simple. A = D squared, Area equals diameter of the cable or wire squared. This calculation is needed when pulling cables into a cable tray so as not to overfill the tray. Over filling a cable tray will build up a heat from the cables if proper ventilation between the cables is not maintained.

If it is brighter than it should be there is too much current and it will burn out early.

This is usually caused by internal problems in the lightbulb, but could rarely be caused by excessive voltage in the circuit powering the lightbulb.

Yes

It is pretty close to 0. I am sitting at a desk. However, I am also sitting on the planet earth which is revolving on its axis as well as rotating around the sun (approximately); the sun is rotating along with our arm of the Milky Way Galaxy, the Milky Way Galaxy is moving through space towards the Andromeda Galaxy and our local cluster is headed towards ... . My head starts spinning when I think of all the calculations required. Besides, what fixed frame of reference can I use to measure all these movements?