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How do i connect 3 leads?
By mhall86, Section Homebrewed Electricity Posted on Tue Nov 21, 2006 at 04:28:00 PM MST
3 phase leads, where to connect

Hello,
I am currently an engineering student and have a current project to create some type of mechanical strain(noise) from windpower.
We were given a floppy drive to use as we see fit. We also purchased a small piezo buzer that will run from 3V-20V. From the floppy drive, we decided to use the drive motor, since it is already connected in a 3 phase system, with a star connection. So now we have the 3 leads, we just do not know what to do from here, whether or not a diode rectifier is needed, or something else.
also not sure which way the magnet should spin with respect to coil direction.
any help would be appreciated
thanx in advance
Natt

How do i connect 3 leads? | 11 comments (11 topical)

Re: How do i connect 3 leads? (3.00 / 0) (#1)
by asheets on Tue Nov 21, 2006 at 09:48:56 AM MST

forget the platter motor and use the head stepper instead. There are too many variables in the platter motor to know which wires will generate electricity, or even if it will do so.

The stepper, on the other hand, is a known quantity. Any of the pairs will generate a current, and there are lots of examples of how to hook up 3, 4, 5, or even 6 wire steppers here on this site alone.

You don't really need a diode to rectify the sine wave (AC) to a half wave (pulsed DC), as the buzzer should work with either.

Finally, all you really need to know is that you have to move a magnet in any vector in relation to a coil to generate a sine wave. Obviously, some vectors are better than others, but any movement at all will accomplish Faraday induction. To be honest, I'm surprised that any engineering school would admit you without you knowing that.
_____________________________

Alan Sheets

Re: How do i connect 3 leads? (3.00 / 0) (#2)
by mhall86 on Tue Nov 21, 2006 at 09:51:32 AM MST

i know what you're saying. It's a second year class, and we have yet to take embedded systems, netwoork, theory , of electrical and signal processing

[ Parent ]

Re: How do i connect 3 leads? (3.00 / 0) (#3)
by asheets on Tue Nov 21, 2006 at 11:26:25 AM MST

Have they made you take physics 1 and 2 yet?
_____________________________

Alan Sheets
[ Parent ]

Re: How do i connect 3 leads? (3.00 / 0) (#6)
by kitno455 on Tue Nov 21, 2006 at 08:54:51 PM MST

hahah, oh, i just blew my drink out my nose :)

allan

[ Parent ]

Re: How do i connect 3 leads? (3.00 / 0) (#4)
by ghurd on Tue Nov 21, 2006 at 11:32:34 AM MST

At the bottom, click Search. Then find story, all sections, containing stepper.
That'll keep you busy for a while. Lots of good info.

Alan is right. If the floppy has a stepper in it, that's the way to go.
It would be hard to hook it up so it did NOT work at least a little.

Some have a tiny DC motor that will run a Piezo, if it is turned the right direction.

If you want to use the 3-ph, I expect the diode losses will be too great for any output.
I would try any 2 of the 3 output leads, straight to the Piezo. It may need a lot of speed to get to 3V.
G-
Ghurd.info

Re: How do i connect 3 leads? (3.00 / 0) (#5)
by asheets on Tue Nov 21, 2006 at 01:28:59 PM MST

Oh, and when you do come up with something, start a diary and keep us posted on your research... I can't tell you how many times I or somebody else here has helped a student only to have that student never come back here again.

It is kind of disappointing, at least to me, to not get any feedback from students that have been helped out here. There was once this AP physics student who was looking to win a prize for the "most powerful" wind generator he could build for under $20. I would have loved to have heard back from him, because we gave him both practical and "show man" ideas that should have wow'd his audience.
_____________________________

Alan Sheets

Re: How do i connect 3 leads? (3.00 / 0) (#7)
by mhall86 on Tue Nov 21, 2006 at 10:54:11 PM MST

so i have done a little more reasearch and found that stepper motor will require 2 full wave rectifiers, connected in parrallel. with the drive motor found 2 different setups:

1 being a 3phase star formation with 2 leads going to 1 full wave rectifier and the other lone lead to its own rectifier.

other being a 3 phase star formation with each lead split going to both sides of its own rectifier. once again all 3 rectifiers connected in parallel.

also had the option of delta, but felt a larger voltage is needed. since deltas are lower voltage, but highercurrent, we chose the star formation.

I think from looking into it, the stepper motor is the more obvious choice,as it is almost guaranteed to work. I was wondering though if the wiring of the 3 phase drive motor would be a complete waste of time, because of little to no voltage created. And if a recordable amount of voltage is obtained, could both motors possibly be connected further in parallel???

ill try and sketch what i mean by this

and i know what you mean about not getting feedback, but dont worry, ill keep you posted on our findings....ohh and by the way, ive only taken physics 1 so didnt really learn about diodes or AC to DC conversion,it was more of a catchup class from h.s. physics. thats y i thought i would ask.

And by asking, i feel ill be much ahead when we are actually taught this stuff next semester.

[ Parent ]

Re: How do i connect 3 leads? (3.00 / 0) (#8)
by ghurd on Wed Nov 22, 2006 at 01:00:31 AM MST

The (most) steppers will give plenty of voltage. No worry about the rectifier losses.

The drive motor will probably have a VERY tough time getting to 3V peak for the Piezo.
Delta voltage will be about 60% of star voltage.

The rectifiers will use up 1.4V of the output. Thats about half of star V, and nearly all of delta V, if it can even get to 3V before the rectifier.

I don't see any need to use both motors with one blade set. The stepper will do it.
I very rarely get a drive motor up to 3V, it will cause additional iron losses, mounting 2 together would be a bugger to align (for me), etc.

Stray thought. 'Brownie Points' still count, right? (trust me, they do)
Make 2 windmills.
The stepper windmill, #1, is a piece of cake.

The drive motor, #2, can be done.
Look at my VCR windmill. You really should read all of it because it covers most of the problems you are facing. Use 6 Piezo instead of the LEDs. Don't use any resistors. The blades may need to be shorter and at a shallower angle (faster).
http://www.fieldlines.com/story/2005/11/25/204242/17

Just for giggles.
The drive motor could be connected to 4 (2 pairs) of Piezo's, and 2 LEDs from the front of the floppy drive.
The stepper could be connected in about the same idea.
Noise AND Light!

The stepper V should be able to handle rectification, a Piezo, and a pair of paralleled (same color) LEDs in a single circuit.

Do not think a decent Piezo needs many ma to make some serious noise. A transistor leaks enough ma to keep a Piezo screeching when they both should be 'off'.

It may help if we knew a bit about the floppy drive they gave you.

And, for me, physics 2 was waved for students required to take electricity 1.
Same material, but physics 2 was shallow and topical, compared to electricity 1.

Do keep us posted,
G-
Ghurd.info
[ Parent ]

Re: How do i connect 3 leads? (3.00 / 0) (#9)
by asheets on Wed Nov 22, 2006 at 11:17:58 AM MST

Can you bring me up to speed a little bit on why you think the platter motor is a 3 phase unit? The specs on the el-cheapos I teach with (I teach college-level IT) is that they are simply 12VDC units that rely more on precision power supply more than anything else to maintain the correct speed.

Since you haven't have Physics 2 (electro/radiation physics) yet, I'd recommend a quick primer on the difference between DC, pulsed DC, and AC sine waves. Here's what I give to my intro Telecom courses.... http://www.appsremote.com/college_development/tel101/Class%202.ppt
_____________________________

Alan Sheets
[ Parent ]

Re: How do i connect 3 leads? (3.00 / 0) (#10)
by mhall86 on Wed Nov 22, 2006 at 04:23:32 PM MST

hello again,
i am prolly wrong, because i know the platter motor is ran off of DC. I was told that when the when the motor is used as an "alternator", hence tha AC , that the 3 coil makeup of the platter motor would become a 3 phase generator.. if this is wrong, let me know, otherwise we could point ourselves in completely the wrong direction. Something tells me it might not be, because of the fact that there is only 1 round magnet utilized.

Since 3 of the leads are all soldered at one point, and there are 3 leads that are seperate, hence a star formation.

would there be some sort of rectifictation taking place inside the circuitry of the chipboard??

anyways, we are going to test the platter motor tomorrow with the full wave bridge rectifiers that we purchased today. Today, we tested with the stepper motor.

when hooked up to the 2 rectifiers, we were able to record a voltage of around 4V. When connecting directly to our piezo buzzer, electrical noise(pulsed DC???) was noticable. Our piezo buzzer runs from 3 -20V DC. now we were trying to figure out how to increase voltage, while "smoothing at the same time. obviously a capacitor would be used, but were unsure of an optimal rating and/or proper utilization in the circuit. I suggested simply a capacitor between DC leads, such as the schematic i drew below.

any feedback would be appreciated,
oh and thanx for the ppt alan, a little refreshment never hurts

[ Parent ]

Re: How do i connect 3 leads? (3.00 / 0) (#11)
by ghurd on Wed Nov 22, 2006 at 09:28:20 PM MST

"Since 3 of the leads are all soldered at one point, and there are 3 leads that are seperate, hence a star formation.
would there be some sort of rectifictation taking place inside the circuitry of the chipboard??"

There is a difference between feeding something 3-ph, and something making 3-ph.
I never saw a reasonably modern floppy that was not 3-ph star.

The platten motor will do a bit better if the bridges are built from Schottky diodes.

"increase voltage, while "smoothing at the same time"
That will make it not as loud. Not nearly as loud.
The Piezo uses very little amps, I hope. A voltage increase will decrease amps. Total watts (power) will be less (losses from increasing V), and the Piezo will not be as loud.
The cap is a good idea.
Is there an Army green rectangle cap a bit larger than an M&M in there? That's the one I'd try first. 2 or 3 is better. The blue ones are OK too. More is usually better for something like this.

Wind power, with close to the right blades, is fast. Pulsing is related to RPM. The pulsing should be minor with a bit of cap.
A 100 ohm resistor between the cap and Piezo will help reduce the pulsing without too much reduction in volume, and the perceived volume may even rise.

Is this a 5 wire stepper? The voltage seems VERY low, even for a 5 wire stepper connected improperly.

How many wires does the stepper have?
(sometimes the output at a higher voltage will go down if not connected properly)
How many ma is the Piezo rated?

From what you have specifically told us about what you have to work with (not much, BTW), I would make 2 bridges with Schottky diodes, each bridge separately feeding a seprate cap and Piezo. Meaning 2 separate circuits fed from separate phases of the alternator.
The `noise' will be louder and smoother.
G-
Ghurd.info
[ Parent ]

How do i connect 3 leads? | 11 comments (11 topical)

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