Help with SG build..thanks

[powerdraw]

guess my questions are too dumb to get an answer so I will struggle on my own and figure things out....

[powerdraw]

Ed- just using single domino size magnets found through the link in the handbook appendicies. Rebuilding coil as advised and hoping will have running wheel.

[powerdraw]

Just gor the R45 (as specified in book) welding rods and about to make a new core..wish me luck..question: I noticed my coil spool is 3.5 inches high where book actually calls for 3.25 long spool..is this difference critical? Before I stuff this coil I will make a new spool if necessary and rewind my wire. Thanks...

[powerdraw]

never mind soory..see you were describing the birdshot R60..I have the right welding rod ordered and will make new core ..There are NO other deviations from build so hoping I will enjoy positive results..thanks again Tom...and thought I did mention the birdshot in an earlier post but no one said anything..glad you did when I mentioned again! I hear you!!

[powerdraw]

Thanks..already building new core ..book says R45 welding rod..I ordered already..you mention R60..are either ok then? Thanks..

[powerdraw]

Here's a rebuild of my "Edsel"..can see how things are wired as book instructs. Seems like wheel wants to run but having trouble finding sweet spot with the trigger variable 1k resistor in series with 100ohm resistors going to transistor base. Think I'll replace with 470ohm fixed resistors skipping the potientmeter. Also has anyone made their cores out of #7 birdshot as Paul Babcock describes? Also worried may have to rewind my coil tighter as I got having to do by hand and it got messy. If anyone sees any obvious faults with my circuit attached, let me know. gonna change my name to "Edsel Builder" ha ha..

[Ed_Morbus]

You use double magnets ?

[Tom C]

you have the wrong core.... wish you would have said so earlier. it is not working at all. you need welding rod R60 steel birdshot wont work. build it EXACTLY like the book says. anytime you deviate from the instructions you will have problems.

Tom C

[powerdraw]

ps...do lights have a polarity? leads are identical length so guessing not?

[powerdraw]

Thanks Tom

Yes..thanks..I wired it exactly as you describe according to schematic with wires out the top of coil to battery connection and bottom ones to transistors. Top trigger to the tramsisor base through the resistor and the bottom trigger to the negative input trace.The attached pictures show where I wired to change mode of running per page 74, point 2 where it describes reversing coil wiring. The change didn’t change anything so I am putting it back and rebuilding circuit in an inline fashion for easier working on one transistor at a time as advised. If my transistors still measure their original gain, should they be ok? Worried if I got any too hot to cause them not to function properly??. Thanks for the assurance on my magmets! I did fill the core of the coil Paul Babcock style with #7 bird shot and it seems like a good working core...hopefully I will be back with my working machine in the near future. Thanks again everyone..

[Tom C]

do you have all the magnets north out? start of coil (the inside wires coming out of the spool) should be on the bottom of the machine away from the wheel, and attached to the individual transistors. end of coil (last wrap off of the spool) is primary battery positive. core needs to run the length of the spool all the way thru. if it is not you are not getting enough voltage into the trigger circuit.

Tom C

[Tom C]

your magnets will be fine, you just need enough to switch the core. sometimes you need a real good spin to get it to fire the first time, its not a self starter. I cannot tell if everything is "right" the way you have things wired up. re wire it flat, start with one transistor and the trigger and work your way up. use the standard electrical troubleshooting steps.

Tom C

[powerdraw]

sorry..just figuring out how to attach so attached messy..

[powerdraw]

Thanks..heres pics of the circuit and wheel. Guess I tried to be too artsy making things circular so hard to work on. Here in wheel pic I had reversed wiring to change mode of running but thing acts same either way. Seems like coil is not getting energized to run wheel. I do see a small voltage oscillating across trigger coil when wheel spins but seems its not activating transistors or if they are switching, the coil isn't doing its thing. Hey..thanks..
Also, I wondered if the coil shaft thickness is critical? Book only specified inside diameter to be 3/4" but is thickmess issue? Also, the neon light leads were identical length so wondering if there is any polarity issue with the lights and how to tell?

[wild weasel]

can you post a picture of your setup? and of the board?

maybe whe can see the fault

regards
weasel