Simple question from a simple guy

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tsindos
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Simple question from a simple guy

Post by tsindos » Sat Nov 05, 2005 9:49 am

This may sound stupid for all people who know anything about electricity but I can't work it out.

Do motors, acting as generators, react like batteries when placed parallel or serial?

I have rigged 3 electric dc motors rated at 3v on a pulley and turn the pulley with a fourth (9v) motor. The motors turn quite fast. I have connected the wires serially to a volt meter and get a reading of just over 3v. I connected them parallel to the voltmeter and get the same reading as before. Does that make sense?
Since I am not interested in Power (and amps) I am just trying to increase voltage using these 3 motors to anything over 6 volts combined - by turning the pulley. How should I connect the wires?

<small>[ November 05, 2005, 09:53 AM: Message edited by: tsindos ]</small>

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Edd
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Re: Simple question from a simple guy

Post by Edd » Sat Nov 05, 2005 1:19 pm

OK…OK…let yet an even simpler guy start the ball rolling with interpreting what I see to be the situation. Just a simple playing around with permanent magnet field / coil rotor toy motors. Initially we should interpret the 3 VDC rating merely being relevant to the wire winding parameters and the brush mechanism capability. Not particularly what you might expect as an output when reversed used in a generator capacity, unless unloaded.
I can see the mechanical coupling of the three units together, along with a powered fourth motor used for spinning them.
As for the series connection of the three and monitoring of the voltage, you didn’t mention if you were privy as to the polarity of the derived output voltages. That being necessary to properly tie them together in a series aiding configuration to effectively harvest their cumulatively added series voltages. As an analogy, it might have been something that you were confronted with as a young kiddo wherein you just dropped 3 cells into a flashlight and it only lit dimly….that being with new cells to boot ! Then you find that you had inadvertently had two cells head to head and they cancelled out.
Soooo…. That is possibly what you might have done with the series aiding connection of the three motors windings…two of them might be canceling out. Sooo… go back and get the “ferris wheel” spinning again and have the windings unconnected and then test voltage output of each one individually , while marking the proper polarity on the motor cases, and then individually series connect them and that way you will properly get their added output. I can’t tell you what that voltage will be as that is relevant to motor speed….but expect as high as you might experience as there is no load imposed upon them , express of the micro loading factor of your metering.
As for the parallel connection of the units, keep the same polarity info in mind with all of the +’s and –‘s pairing up and effectively then you should expect an increased current capability, IF a loading was than imposed on the trio’s output.


73’s de Edd
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Wooooops....looks like I might have inadvertently zinged a nudist(s)....most honorable apologies....if necessary.

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<small>[ November 07, 2005, 10:54 AM: Message edited by: Edd Whatley ]</small>

josmith
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Re: Simple question from a simple guy

Post by josmith » Sat Nov 05, 2005 2:28 pm

In a word yes they should react like batteries adding voltage in series and adding current in parallel. Other than Ed’s explanation that you messed up the polarity they should have. The three volt rating needs a speed associated with it since voltage and speed are directly proportional on p.m. motors. Ideally if the motor were rated at 3v and 5000 rpm it would run at 5000 on 3v and generate 3v at that speed. Actually it would run a little slower and generate a little more voltage..

Robert Reed
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Re: Simple question from a simple guy

Post by Robert Reed » Sat Nov 05, 2005 4:36 pm

Tsindos
You may require diode isolation of each motor/generators "hot lead" when operating in paralel.

josmith
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Re: Simple question from a simple guy

Post by josmith » Sun Nov 06, 2005 3:32 am

"Puhleeeez tell me….Why...(gone and forgotten quote)

Perhaps it's not about You!

Certainly no place for this here.

<small>[ November 07, 2005, 04:03 PM: Message edited by: josmith ]</small>

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jwax
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Re: Simple question from a simple guy

Post by jwax » Sun Nov 06, 2005 5:20 am

"Cirtainly no place for this here."
What do you mean josmith, bad spelling?
"contributors" to the forum get respect, commentary/opinion gets ignored.

josmith
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Re: Simple question from a simple guy

Post by josmith » Sun Nov 06, 2005 8:13 am

If it's ignored why are you commenting on it?
In the past a majority has supported zero tolerance for any off color subject matter. Our more respected "contributors" should be setting the example.

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Chris Smith
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Re: Simple question from a simple guy

Post by Chris Smith » Sun Nov 06, 2005 8:18 am

Also apply a cap to the out put, you might not be summing the DC which is like AC, in that the pulses of DC are not being properly counted in the DC mode on your volt meter.

The cap will store the pulses, and feed the meter with the sum voltage. [ripple removed]

<small>[ November 06, 2005, 08:20 AM: Message edited by: Chris Smith ]</small>

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Re: Simple question from a simple guy

Post by Robert Reed » Sun Nov 06, 2005 4:59 pm

"Puhleeeez tell me….Why is it that most,specifically (99.86/100 %), nudists are people you wouldn't EVER want to see naked? "


WHAT IS THIS ???

Dean Huster
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Re: Simple question from a simple guy

Post by Dean Huster » Mon Nov 07, 2005 5:59 am

Most toy motors have at least a 3-segment commutator, so the output at least is a minimum DC level. Small caps will be fine for experimenting with a meter but it'll take some pretty hefty ones to help out with heavy loads. I'd guess that caps overall, with a heavy load, would be pointless as the average DC level will still be about the same.

tsindos, you may quickly find out that when driving just a single motor as a generator, if you short the "generator" output, you'll darned-near bring your motor-generator to a halt, proving the fact of the conversion of mechanical energy to electrical energy.

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

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