motor : 3 phase .5 h.p 440 v star connected motor\nwithout connecting the capacitor of 2.5 micro farad the voltage is 1v across the terminals and it just fails to buid up.can anyone plz help
213014
An induction motor will not work as a generator because there is no way you can create the magnetic field. You need some sort of magnetic field to make a generator work.\n\nIn order to induce a voltage you need three things:\n1. A conductor capable of carrying current\n2. A magnetic field\n3. Relative motion between the two.\n\nA generator either 3 phase or single phase, will have a rotating field. Power to this field is supplied via brushes and slip rings. See if you can find an old alternator from a car to take apart. Alternators are really 3 phase AC generators. The DC for the car is created using a set of diodes that you will find inside of the alternator. The diodes are often encased in plastic.\n\nA drill motor or other motor that has a commutator (a group of coppers bars that run parallel to the shaft) can be modified to be a generator, however it will produce a DC output.\n\n(Added 5/3)\nYou are correct that a voltage will be induced, however it is being induced in a place where you can't get it. An induction motor uses a squirrel cage rotor. When connected properly, the rotating magnetic field of the stator induces a voltage in the rotor. This voltage creates a magnetic field that causes the motor to rotate. However, since there are no slip rings or other connection to the rotor, there is no way for you to draw off the power generated. \n\nTo make a long story short, an induction motor can not be used as a generator. It simply does not have what you need to work.
128991
well, figure that you have 24,000 Kilowatts at your disposal.  Running at 400 Volts.  Power=Current * Voltage.  This is a rough estimate! So roughly 60 amps MAX coming out.  I would refrain from anything that draws more than 40 amps.  Also I would check with the company that made the generator.  You don't want to get crossed into that kind of power.  Believe me.  I've taken hits from a fully charged 50KV capacitor.
56889
Aboslutely, provided the fans are for 12V service.  Leave the secondary center tap unconnected, and put each end of the secondary to the AC input of the rectifier.  The + goes to the red lead of the fan; the - goes to the black lead (traditionally speaking of course.) Now the supply will be very ripply, with a 120 Hz waveform which could be more than a volt.  If you put a 470uF 35V capacitor across the plus and minus of the rectifier, you will smooth out the ripple, but increase the voltage above 12 volts.  Make sure the fans can take the increased voltage.  Transformers are rated at the RMS output at the 3 amps in your case.  The peak voltage will be around 1.4*12.6, but in practice I have never seen it go above 15 V with a load.  Therefore at 1 amp, if you put a cap on the supply, it may produce excessive voltage.  Check it with a voltmeter-- you may luck out.\n\nI have been in a similar situation.  Get a 5 watt resistor at maybe 1 to 3 ohms.  Insert it in series between the capactitor positive and the fans wired in parallel.  When running, use a voltmeter on the fan circuit.  Increase the resistor till you get 12V or thereabouts.  The resistor will get hot, so leave the leads long and connect them to a terminal strip or block if possible, and mount it in the airstream.\n\nCheck out the LM7812, however, at 1 Amp.  Google it, or check out jameco.com for the part.  Put a 470uF at 35 V at each end of the regulator to keep things very smooth.  Your fan will run perfectly with the voltage regulator.  Be sure to mount the tab on a heatsink to keep it cool since you are running it at full capacity.
80279
You will need to get a DMM (digital multi meter)...Walmart has these pretty cheap.  \n\n1) Before doing anything else, check the fuses again.\n\n2) Unlug your fan from the harness it is comming from.  Put the DMM on continuity (ohms) or if it has the tone option, put it there.  Now put the 2 leads together (probe to probe). Take note of what the display says.  Now put one probe on one wire comming from the plug on the fan, and do the same with the other probe on the other pin. Your display should read the same (continuity) or beep.  If it does, your fan is good.\n\n3) Now put that DMM on DC voltage (12 volt range up to 25, depending on DMM).  Again, one lead on one wire, other lead to the other wire.  Start your car, and turn on your a/c (this activates the fan circuit regardless of temperature).  If you get power, you know your relay is fine.  Now turn off your a/c and let the engine heat up to normal.  If your power does not come back, you have a temperature switch gone bad.  If it does, you have a problem with the fan (which you should have found in the last step).\n\nHope this helps!
596398
I fix this problem everyday.  You have a loose DC JACK.  If you have a sony, you just have to buy a cable that plugs into your power board.  Most likely it is a sodered on dc jack.  This means you have to get the specs of your mother board, order a new dc jack and desoder the old one off and soder on the new one.  Takes about an hour once you have the part.  If its just the cable your in luck. Try "with the battery taken out" wiggling the dc jack (where the power cord plugs in."  If you can feel it moving thats what it is. Your in luck, its an easy and cheep fix.  You could pick up that part for 10 bucks or cheeper.
489255
Nominal= 36ohms\nTolerance=5% \nMultiply nominal by .05 , then add that figure to nominal for Max,.subtract it from nominal for Min.,,and study your ohm's LAW!! ;-)=
596245
Take it in to a shop and have them look at your power supply. It sounds like that could well be your problem. If so, it is a fairly easy fix. Trust me, it happens way too often of late. Good luck.
578534
Try reading the manual. I know its difficult but it could work, or maybe go to where you got it.
251537
Okay it seems that you have a dc motor, a transformer and a switch. I would imagine the transformer is a multi-tapped step down. You can verify this by disconnecting all the secondary wires from the transformer and putting power to the primary. Get a meter and go from the common on the secondary side and to every output on the transformer. If the wires on the transformer are color coded the common may be black and the hi output may be red. Other colors will be different voltages. If this is the case the switch is wired with the exception of the secondary common through multiple poles to provide different voltages to the motor. The switch will have a common output and all other wires will be inputs from the transformer. The output of the switch then must go to a rectifier of circuit board that converts the voltage from ac to dc. This connects to the motor. You might be missing the ac to dc converter circuit if you dont see a circuit board or Bridge rectifier. If you go throught the switch wiring and get it set up to where you have different voltages at the output of the switch you can always go to your local parts store and buy a 2 amp bridge rectifier. The common output of the transformer will have one wire going to one of the ac sides of the rectifier and the other will go to the other ac side of the rectifier. The two remaining outputs will go to the motor and polarity will not matter. Hope this helped!
335066
make sure you have them connect to 12 v, not 5 v, they should run at about 2500
527533
Check whether the power cables from the motherbaord to the powerswitch are connected properly. It could behave mad if the connection is not proper !!!!
483545
I have already answered part 1. in another question you've asked. I think you probably didn't use the right units (like cm needs to be convered to meters) and got the wrong answer.\n\nNow for part 2:\n\nInduced EMF, ℰ = -L(di/dt)\n\nwhere i is the current and L is the inductance\n\nWe are given that the magnitude of the induced current,\n\ndi = 47 mA\n\nand the oscillation frequency is 100 Hz. This means that dt = 1/f = 0.01 sec\n\nWe have L = 8.44 × 10-^3 henries from before\n\nSo |ℰ| = L(di/dt) = -(8.44 × 10-^3)(0.047)/(0.01) = 0.0397 volts\n\n------------------------------------------------------\n\nNow part 3 has to do with mutual inductance:\n\nVs = VpNs / Np\n\nwhere \n\nVs is the voltage across the secondary inductor, \nVp is the voltage across the primary inductor (the one connected to a power source), \nNs is the number of turns in the secondary inductor, and \nNp is the number of turns in the primary inductor. \n\nTherefore Vp = VsNp/Ns and Vs = 0.0397 volts as calculated before, so\n\nVp = (0.0397)(197)/(2920) = 0.00268 volts
74068
did the casse come a motherboard?, or did u just transfer the motherbaord to the new case??\n\nIf so, you may have zapped it, with Static Electrcity\n\nor\n\nSome motherboards require a 2nd hook up a 4 prong to add extra voltage, check with your motherboard manuall if you got a new mohterboard
84988
Are you applying power via a Variable Frequency Drive?\n\n\nCheck out the following link:
211417
You'll need, as the name may suggest, a voltmeter.  Also applicable is a multimeter - which you'd then set to voltmeter mode.\n\nAt which point you'd just put one contact on one one end of the battery, and one on the other, and see what the equipment reads.\n\nMy money's on 1.5V :)
231566
You cannot run polarized electrolytics backwards, without destroying them. You can find dozens of different non-polarized types on-line from parts distributors such as Mouser, Allied, and Digi-Key. But if you want to get around the problem, there's still another way; Place two standard polarized electrolytics in series, "back-to-back" so that their negative terminals are connected to each other. Then, place a rectifier diode, such as a 1N4002, in parallel with each capacitor, so that the cathodes are in contact with the positive capacitor terminals, and the anodes are in contact with the negative capacitor terminals.  What you will have now made is a "bipolar" or "non-polarized" capacitor that is roughly equivalent in value to one of the two original polarized capacitors!  If, for example, both of the electrolytics were rated at, say 2200 MFD @ 25 VDC, the new "homebrew" NP capacitor will function as a 2000 MFD, 25VAC capacitor!  Reversing polarity on this "home brew" capacitor will not cause any problems, whatsoever!
193401
Sounds to me like the voltage switch if you mean the little red one that looks like the one in this picture:\nhttp://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-4Y67VN\n\nThat will require a trip to a computer store and likely some new hardware. Possibly just the power supply ($50 or so) but perhaps much more; like the motherboard/CPU and RAM. The PSU probably got more voltage than it should have and the 'magic smoke' that makes it work leaked out.\n\nGood luck.