Quote from: LarryC on March 31, 2008, 09:23:26 PM
...I noticed that some non testers thank that they are asking for information from their corporate research department, not the basement/kitchen table researcher on this blog...Ã, 
LarryÃ, 

There are only two main things missing, as far as I can see:

1. An in-line ammeter to measure the input current in the transformer experiment. It should be possible to pick one up with sufficient accuracy/resolution in a used/surplus store for well under $50. Or else to borrow one from the U. This is not a hard piece of gear to find. The clamp meter is a problem and the new clamp meter will continue to be a problem because it has +/- 5 digit error spec.

2. A torque meter to reliably measure the torque in the shaft between the motor and the device. This is important for determining how much power is being transferred (torque x rpm), and will also allow the measurement of the torque/speed curve for both the motor and for the device so the stability/instability mechanism can be observed. I don't know anything about torque meters - may be a lot harder to find at a reasonable price than the ammeter I think. How about this: http://www.lorenz-sensors.com/frame/torque.htm

PB

Quote from: OilBarren on April 01, 2008, 07:18:19 PM
HERE IS THE QUESTION AGAIN...
1 HIGH VOLTAGE COIL (270 ohms) CAUSES ACCELERATION WHEN SHORTED
1 HIGH CURRENT COIL (55 ohms) CAUSES DECELERATION WHEN SHORTED
THEY ARE MOUNTED ON THE SAME CORE
SO WHY ARE THEY PRODUCING DIFFERENT RESULTS?
I HAVE MY IDEAS BUT - I WANT TO HEAR FROM OTHERS.
Thane

1. What is the initial steady-state rpm?
2. When you short the HV coil and it accelerates, does it re-stabilize at a new higher rpm (if so, what rpm?) or does it go on accelerating?
3. When you short the HC coil and it decelerates, does it re-stabilize at a new lower rpm (if so, what rpm?) or does it go on decelerating?
4. What's happening in your green coil for all of this? Is it open, shorted, loaded etc? Are you changing that at all?
5. Is there any electrical connection at all between any of these coils?
6. How many turns on each coil (ie the green one, the HV one and the HC one?)
7. What happens with both HV and HC coils shorted (but not connected together)
8. What happens if you connect the HV and HC coils in series and short the free ends?
9. What happens if you do #8 but reverse one of the coils so they're out of phase?
10. What is the meaning of the universe?

PB

HERE IS THE QUESTION AGAIN...

1 HIGH VOLTAGE COIL (270 ohms) CAUSES ACCELERATION WHEN SHORTED
1 HIGH CURRENT COIL (55 ohms) CAUSES DECELERATION WHEN SHORTED
THEY ARE MOUNTED ON THE SAME CORE
SO WHY ARE THEY PRODUCING DIFFERENT RESULTS?
I HAVE MY IDEAS BUT - I WANT TO HEAR FROM OTHERS.
[/quote]

Thane,

Mr Others back to you here.... lol

This is quite fascinating, especially what appears to be your use of MOT cores and coils.

May I ask some construction pointers? 

1) It looks like the single Lee Valley cup, but with two 1/8th thick magnets in it?

2) It looks like two MOT cores with the outside legs cut off?

3)The two cores are mounted on a back steel piece to tie them together?

4) are they clamped down tight or is there a spacer block between the mot core and the transverse
core? (or an air gap?)

5) are the two mot cores one magnet spacing apart? (do the cores align on each magnet)

6) are the magnets NSNS or NNNN?

7) The two gold coils are the primary and secondary from the Mot?

The green coil is hand wound?

To answer your question, I would have to know if the green coil and gold coil are connected....

Ron the builder, in sunny Victoria

All,

Update to low cost test equipment research in blue. Actually PB has reminded me of Prony Brake information that I had forgot to post earlier:

An article to buy an accurate digital Tachometer using a magnetic sensor for less than $25 at http://www.instructables.com/id/Tachometer-made-from-a-bicycle-speedometer-cycloc/. The Cateye unit used in the article is not available anymore. I found a newer version, which is a Cateye Velo 8. Got it today, set it up according to the article and it correctly measure the two speeds of my Ryobi drill.
It was $22.56 including shipping from BikeWorldUSA.com.

An article on building a Gaussmeter for as little as $6.00 at http://my.execpc.com/~rhoadley/magmeter.htm. The hall effect IC in the article is discontinued. The replacement is the Allegro A1323LUA-T. Digi-Key has it for 1.45. Found out that Digi-Key will not have it in stock until May. I'll try to find other alternatives.

Wanted a low cost Wattmeter that can measure milliwatts. Couldn't fine one, so I've ordered the Kill-a-Watt meter for $21.49 including shipping thru Amazon.com. Displays active power and apparent power in whole watts.

An article on how to build a Prony Brake ( used to measure shaft power of small motors) can be found at http://www.geocities.com/koneheadx/measuringshaftpower.html. Vince has built one for his Thane motor and can probrably add some insight.


Regards,
Larry 

Quote from: polarbreeze on April 01, 2008, 08:16:05 AM

Quote from: Mr.Entropy on March 31, 2008, 10:13:54 PM
If this were the case, howerver, then disconnecting the coil would increase the extent and depth of the accelerating speed range and cause the rotor to accelerate further instead of slowing down as it does. 

I disagree with that. Don't forget that instability can go in either direction. It can EITHER result in acceleration OR it can result in deceleration. It just depends on which way the system starts to go when the instability first sets in. The point is that it tends to move AWAY from its previously stable speed/torque, but it can be in either direction. That topic was described in the paper I just posted a link to.

Interesting.  You would not be able to draw a set of torque vs. speed curves for the motor, disconnected load, and  connected load that would allow this to occur.  Why do you believe that you could?

Quote from: polarbreeze on April 01, 2008, 08:16:05 AM
I don't see a justification for your statement that the boosting is "not plausible given reasonable estimates of the rotor inertia, coil inductance, and motor torque curve" but if I've missed something, please explain it to me.

I cannot point out your error until you show your work.

Cheers,

Mr. Entropy