What is the appropriate amp draw on the SSG when tuned to perfection?

[Yaro1776]

Hey Paul,

You are welcome!

OK, well if my gap between the coil and the magnet is only 1/8 of an inch or 6.35mm I may be too close and drawing too much at 1.6 amps. I might work with backing the coil away from the magnets some and see how the draw is on the primary.

I tweaked my wheel bearings and was able to up the RPM (about 275) - of course, in this instance my draw went up to 1.56 amps or so. I am not really concerned about the amp draw at this time - still early in the game to obsess with this type of detail. Yes, I did finally do a freewheel run - my improvements increased the freewheel time to 120 seconds. Still, pretty ugly...

Yaro

[Silver9]

I know Yaro I'm working on the same thing I need to remove my coil to see how long the free wheel time is. With the coil in place is not a good way to test free wheel spin, but I already got my coil soldered into place so I might just take the wheel off and try to mount it to check for free wheel spin. I did remove the hub and bearings and grease and sprayed with very light oil, and when I give the axle a spin, it spins very freely. More testing to do!

[Yaro1776]

Keep everyone up to date on your progress! I am still dinking around with the bearings on the wheel and if the RPM and freewheel time does not go up more, then I will go to plan B. Plan B is getting another wheel with different bearings - more in line with what Tom C. has been recommending.

Picked up another NAPA 8224N battery and have started to condition it - can be a lengthy process... Using the technique outlined by John K (I believe) in Branch Gordon's thread.

My coil gap is running about an 1/8" or less. There does not seem to be much of an RPM variance in this gap if you adjust up or down by a small amount (1/32"). Amp draw remains relatively steady around 1.52 to 1.55 amps.

Later,
Yaro

[rsargent52]

Playing with my new setup and have a few questions -
I have been varying the gap between coil and magnets from 3/16" to 1/8". I have 19 magnets and from original SG videos John speaks of having an odd number of magnets and not evenly spaced - so I didn't worry about spacing. They are spaced from 2 3/4" to 3 1/4" apart. Issue I am seeing is the LEDs do not light up and the secondary battery charges pretty slowly. The primary is also draining slowly. the batteries are both 12v 8ah AGM sealed units - motorcycle batteries. I started the secondary at 12.2v. After charging on last run of 15 minutes it moved up from 12.1v to 12.5v while the primary discharged from 12.98v to 12.74v. I noticed after the batteries sit a while the secondary loses some charge and the primary gains some - is this normal?

Following directions, I tried to place an ammeter between primary battery negative and the Primary - post on the board but would not work - just shuts down power. Where should I take the Amp check?

What are people using for measuring RPM?

Thanks...
Randy

[romeo-kilo]

Randy,
it is normal (after stopping the SG) that the output battery reduces voltage, and the input battery recovers a bit.

There are two positions for your analogue amp-meter:
1. In series to the input battery (to measure the input amps)
2. In series to the output battery (to measure the output amps)

Please remove the amp-meter after reading the current, as it influences the efficiency of the SG. When you remove it from the output, stop the machine, otherwise your transistors will die.

For measuring speed, I use a cheap bicycle speed meter which measures via a magnet. When you know the size of your wheel, you can calculate the RPM's from the speed.

Ralf

[Yaro1776]

Randy,

Ralf's explanations on the battery voltage are on the money and his tips on placing the analog meter are on target. I tried a digital meter at first and blew the internal fuses. A cheap analog meter that is rated for max volts and amps with a moving needle will get you the info you need (someone out there has a good source). If you are flush a clamp-on DC amp meter will work also, the amperage reads will bounce around a bit, but you can estimate closely the mean.

For the RPM a bicycle speedo works very well. Check post number 21 http://www.energyscienceforum.com/sh...?t=1286&page=3 for a more detailed setup of the speedo to give you a direct RPM read. Others have recommended a laser tach that can be found for cheap ($10-$12) on the web. The bike speedo is my preference since it reads continuously and the speedo can count the RPM and time elapsed during an SSG charge run if you are so inclined.

I have been using a couple of lawn tractor batteries (230 CCA) taken from my mowers for all the initial tuning of the 8 trans SSG with 21 magnets. Still a few issues with the freewheel speed of the wheel, but it does rotate at 275 to 280 RPM and outputs about 0.75 amps to the Charge battery. Coil gap spacing is about 1/8" for best RPM as it stands now. When the wheel freewheel time gets to where it should be then this will undoubtedly change.

Certain that more experienced builders will give more specific info to your questions.

Yaro

[Tom C]

I use a digital tachometer
http://www.ebay.com/itm/Non-Contact-...item20de8a75a0

I am not sure where JB said uneven...... we have always recommended spacing magnets evenly, and the plexi kit that came out magnet spacing was important. your machine will charge better and run smoother with evenly spaced magnets..... the rim cannot go into resonance with the coil if they are not evenly spaced.

Tom C

[rsargent52]

Ok, cool - will look at spacing magnets evenly. I must have misunderstood what he was saying. Found my meter only reads AC amps - so I will hunt down the analog unit.
Thanks, guys for the other info. Will keep playing with it. The laser tach sounds interesting - that was what I was doing some searching for, but since everybody is happy with the speedo, will go that route. I can go back to the bike shop that gave me my wheel.

Randy

[rsargent52]

One last question before I rip my wheel apart - is there a bad, good, and best spacing for magnets on the wheel?
Thanks...

Randy

[rsargent52]

Yikes - I just blew out 2 analog ammeters! I guess they were a little too cheap! Made in China stuff.
Before it died it was bouncing back and forth rapidly between 0 and ~ 1.9 amps. Maybe the bouncing killed it.
But the good news is I my wheel is spinning much faster. Working on getting a good speed indication now.

[rsargent52]

So I after rebuilding my SSG and got a speedometer installed for calculating RPM I have been playing with gap between magnet and coil. Been using a stack of business cards that I measure with a micrometer and use the stack to establish gap size. Playing with gap from 1/8" to 5/16" and am spinning at about 260 - 270rpm. Think that is working well.
My question is on the ammeter. As mentioned above I blew out my analog ammeter - it was pounding back and forth as each magnet passes the coil. I think it just beat itself to death. Are there any ammeters that equalize a little? Any recommendations on what I should buy?
Second question - when the wheel gets rolling up to speed the unit starts making a loud snapping noise - is this normal?
Thanks...
Randy

[Tom C]

do you have packing tape around the perimeter over the magnets? , you may be hitting a magnet on the coil when it passes. get a DC clamp meter
http://www.extech.com/instruments/pr...=26&prodid=814

Tom C