lovescamaros28

I think this guy totally messed up Ohms law.Voltage goes down and amperage goes up? I dont think so(lol). http://www.trineonline.com/interior/...lectronics.htm

The last time I checked. I=E/R If voltage goes up and resistance stays the same amperage goes up.

lovescamaros28

This goes with what I learned years ago.http://www.blackboxvideo.com/ohm's_law.htm

bearcatt

iTrader: (41)

In a series circuit, the voltage drops/divides and the current stays the same. The voltage dropped/divided equals the voltage supplied.


In a parallel circuit, the current drops/divides and the voltage stays the same. The current equals the current supplied.




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fleetmgr

He's right, if you change one of the terms of Ohm's law. Try P=EI where P=power (watts). Or, to put it into context - to maintain power with reduced voltage, current has to go up.

See this: http://www.hvacwebtech.com/Ohm's%20Law.htm

lovescamaros28

I am referring to the chart that states when voltage goes up amperage goes down,and when voltage goes down amperage goes up.This is what is wrong.Say I have 2 ohms and 6 amps.Since Ohms(R)X(I)Amperage=Voltage....In this case I would have 12 volts.If I ((increased)) the amperage to 8 amps,I would end up with 16 volts if ohms(resistance)stayed the same(2x8=16 for the slow ones).Amperage went up and because this amperage went up it obviously has more electrical pressure(voltage).Therefore,when Voltage(pressure)goes up Amperage(current) goes up.The only time that amperage would go down with an increase in voltage is if the resistance went up.Please feel free to explain how this guy is right and all these links are wrong...http://solarious.wordpress.com/tag/ohms-law/ http://answers.yahoo.com/question/in...3182331AAT9rry...http://books.google.com/books?id=h3P...sult&resnum=10...www.autoshop101.com/forms/h2.pdf

lovescamaros28

Exactly...Eventhough the voltage does drop across each load in a series circuit,the amperage(current) remains the same throughout.Amperage never does increase with a decrease in voltage though.

bearcatt

iTrader: (41)

On basic DC powered series circuits, ohms law is ohms law.

Talking about AC powerline transmission, that is a different thing or even an AC circuit for that matter. The voltage is inversely proportional to current. Like a transformer for instance.

Step up voltage transformer: step down current.
Step up down transformer: step up current.




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bearcatt

iTrader: (41)

On the otherhand here's another perspective.


http://www.hobbyprojects.com/ri_in_A...C_circuit.html


Like said in that link, the voltage has to be RMS or peak.


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2002_Z28_Six_Speed

iTrader: (19)

What is the point of this thread?

That you found an error with something posted by a non professional on the internet?

Pat yourself on the back for that one.

fleetmgr

From Grainger, item 1F804 Permanent Magnet DC Totally Enclosed Fan Cooled Motor, HP 2, RPM 1750, Armature DC Voltage 180 VDC, NEMA Frame 143TC, Mounting Face/Base, Service Factor 1.00, Bearings Ball, Full Load Amps@Nameplate Volts 11.6, Thermal Protection None

From Summit, SUM-820323 12v DC 1.9hp. Other specs not stated. We all know that starting current can, depending on conditions, be well over 100 amps.

Also note that this motor would be fed with a #4 or #6 cable to accomodate those conditions. Duty cycle is maybe 10%.

To feed the Grainger motor, all that would be needed is #12 wire to keep it happy at full load, 100% duty cycle.

I'll note that the differences here are .1 horsepower. Both are DC motors. As the supply voltage went up, the current requirement went down.

You see the same differences in AC circuits, depending on what you are trying to accomplish. Look at the current requirement differences between equivalent cooling capacity 110v and 220v air conditioners.

Go back to the link I posted previously, and go to the bottom of the page to see ALL the permutations of Ohm's Law.