Induction brass annealer redux
- Thread starter Gina1
- Start date
Large gauge wire is not a problem and I didnt do twisting of the two I did try to keep them short. that meant putting the current shunt sort of inline between the power supply and the board. Likewise the contactor. by keeping them short this way twisting them was never going to work anyway.
Splitting the wire to connect at different posts on the power supply is not a problem all three are connected together one the PCB anyway, so it is a good solution.
I find other areas on the PCB to be much more of a heat issue. Particularly the wire wound inductors and the PCB at the coil post connectors to the board and back to the mosfets. I ended up reinvorcing all that area by soldering the posts to the board and together and adding wire to the pcb traces from those back to the mosfets. Also some stick on heatsinks below the capacitors. However I find the capacitors are much less of a heat worry than the other areas.
Very nice design of the platform. Also interesting what you have done with the coil.
Splitting the wire to connect at different posts on the power supply is not a problem all three are connected together one the PCB anyway, so it is a good solution.
I find other areas on the PCB to be much more of a heat issue. Particularly the wire wound inductors and the PCB at the coil post connectors to the board and back to the mosfets. I ended up reinvorcing all that area by soldering the posts to the board and together and adding wire to the pcb traces from those back to the mosfets. Also some stick on heatsinks below the capacitors. However I find the capacitors are much less of a heat worry than the other areas.
Very nice design of the platform. Also interesting what you have done with the coil.
It is just under 1/4" in diameter, so its either a 3 or 4 (don't remember which).
The split connection is on the connection at the ZVS board end of the wire that connects it to the coil. Just for clarity, my coil is NOT mounted to the ZVS board in any way...it is connected by the large (3 or 4) guage wire. The ZVS board is powered from the power supply (through the ammeter and the relay) with 14 guage wire.
Thank you. There is a guy on YouTube (FrenchCreekValley) who did some experimentation with 1, 2, and 3 layer induction coils for annealing rifle brass...interesting watching. I decided that the coil he called 'good' was good for me to start with...I didn't want any thing that was too fast because that makes it more difficult to determine an appropriate timer duration for any given caliber/brand/lot # of brass without risking overshooting and overcooking your brass.
Also, I tried doing the winding with the fiberglass sheathing in place, but it got partially shredded during the process, so I removed it. It did, however, provide spacing so there is no contact between coils...and so no shorting.
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Ah sorry in that case it is probably better to twist them then. I would also not go with a wire that is made up of very fine wires like a "Litz" wire or what is termed in other circles welding cable or flexible high current wire. This wire is not going to be suitable for this frequency. Splitting it over the three terminals I don't think is a bad thing at all. Like I said I Soldered all those terminals together and added wire from those too the mosfets to try and stop some heating. They are carrying 15-20A so they need to be low resistance to stop heating.
No, its not fine strand at all...probably 13 or 14 strands of 16 or 18 gauge. So, would a solid 10 gauge be less resistance than the stranded 3 gauge? It would certainly be easier to work with...
Here is a rough circuit diagram: https://drive.google.com/file/d/16gGj4jPtPGdh--QO44VOZwWJYbIx4TM6/view?usp=sharing
Here is a rough circuit diagram: https://drive.google.com/file/d/16gGj4jPtPGdh--QO44VOZwWJYbIx4TM6/view?usp=sharing
Just my two cents..
The original GineEric design (and there have been many changes over the past 3 years) used part of the induction coil to connect directly to the ZVS PCB. If you look at the first page (coolant diagram) of this thread, you can see that the coolant is connected to the induction coil before it runs through the the ZVS board. In your case (using 1/4" copper tubing for the coil) and extending it out to the ZVS and connecting it there, would give you an excellent, low resistant conductor, and the coolant would remove any heat if generated in it.
Gina
The original GineEric design (and there have been many changes over the past 3 years) used part of the induction coil to connect directly to the ZVS PCB. If you look at the first page (coolant diagram) of this thread, you can see that the coolant is connected to the induction coil before it runs through the the ZVS board. In your case (using 1/4" copper tubing for the coil) and extending it out to the ZVS and connecting it there, would give you an excellent, low resistant conductor, and the coolant would remove any heat if generated in it.
Gina
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He wants flexibility in placing the induction board rather than rigidly tying it to the work coil.
Shorten the wires up as much as you possibly can and move the induction board to do so if you can. Remember you have a ton of amps flowing through these (multiples if what is shown on the ammeter). As Gina notes, in the original design the connection to the coil (as well as the coil) is cooled, plus it is heavy copper tubing (low R) and short.
When I made the reference to twisting wires I wasn't talking about the connection between induction board and work coil. I meant all other wires - particularly the connections to the main power supply and onward to the induction board. Parasitic induction can play havoc with the board's MOSFETs. Twisting wire pairs is just 'good practice'. It's not the cause of the heat issue you are noting.
Shorten the wires up as much as you possibly can and move the induction board to do so if you can. Remember you have a ton of amps flowing through these (multiples if what is shown on the ammeter). As Gina notes, in the original design the connection to the coil (as well as the coil) is cooled, plus it is heavy copper tubing (low R) and short.
When I made the reference to twisting wires I wasn't talking about the connection between induction board and work coil. I meant all other wires - particularly the connections to the main power supply and onward to the induction board. Parasitic induction can play havoc with the board's MOSFETs. Twisting wire pairs is just 'good practice'. It's not the cause of the heat issue you are noting.
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The wire connection of the coil to induction board is strictly for flexibility of the coil mount so that I can adjust the height of the coil for different sizes of brass case without having to move the largish induction board also. As I designed it, the piece of Corian that holds the coil can be slide up and down and secured with a plastic bolt/nut as seen in pics 2 and 3 in my original post. The coolant tubing is plenty flexible to allow for full movement of the coil when attached...I just needed the electrical connections to be as flexible.
As previously noted, I can probably reduce the length of those connecting wires by about 30-40% as is, but if I increase the height of the standoffs supporting the induction board I could probably get another 10% or so.
Done deal. I always twist the ends of a stranded wire before crimping into a connector or clamping into connection block.
Bottom line, I beleive the answer to my original question is to shorten the connecting stranded wires, not switch to a single strand, large gauge (ie 10) wire. Thanks SGK.
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I don't just mean twist the ends. I mean twist the positive and return wires together. This was the stray inductance is cancelled.
Shortening the wires may not be enough. There's a reason why we move the shelf and not the work coil. But given your layout it's the right place to start.
OHHH...I get you now.... (no I didn't)
Edit: Some of the pairs are twisted and some aren't. Some pairs separate and go off in different directions to switches, buttons, and relays, etc. I will see if there are any pairs that I can improve on...thanks.
Buuut...just to be sure...if I was to twist the pair between the induction board and the coil would that help with any strays there and the generated heat issue?
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First of all, let's give credit where credit is due:1 - TO Gina/Eric, the originators of the DIY induction annealer:
Last year, I built an annealer following their spec - PLC controlled and with a motorized gate platform (Up/Dn).
More details on page 52
2 - TO ootts:
His published Arduino code was my first textbook for programming.
His challenge to share code ideas is quite commendable.
Here is my approach - The loop function monitors various user choices and sends
the executions to individual functions like:
- Anneal (3 modes of operation TEST, ONES and AUTO)
- Up/Dn the Gate platform
The platform is moved by 2 step motors.
It stops at pre-programmed levels for 4 different calibers (for now).
- Constant update of the 4 line screen - level, volts, amps, time, etc.
- The drop gate is activated by another step motor.
- Two LED indicator (Green, Yellow) help the user to time the feeding sequence.
- There are also several functions for "housekeeping" - Emergency stop, contact bouncing, memory, relay controls, etc.
3 - TO David101 for the idea to use inexpensive Power Supply and ferrit (Fluxion) based inductor.
The annealing system is air coooled - closely installed components and two high volume fans maintain coil temperature around 140-150 degrees.
The configuration of the ferrit allows accuracy of heating only the case neck and part of the
shoulder. Thus, the required annealing power is low (average - 38 volts, 9-10 amps, 5 - 6 seconds).
In addition, the rest of the case does not get any direct magnetic hits. Thus, IMHO,
the annealing time could be increased safely for longer cases with no overheating of the lower part. Further tests would determine this.
Oliverpsmile that is a really nice solution physically and you have hit it out of the park technically. The case design is really smart looking and looks like very functional. I cant believe how many people have made units that look like they surpass the current commercial units available.
oliverpsmile... Thank you . Never would I have ever imagined that that from the simple GinaEric induction annealer, folks like you would build these incredible variations.
Some how I feel like Tomas Edison, looking into the 21st century, and seeing everyone using cell phones.
All I can say is "Well done"
Gina
Some how I feel like Tomas Edison, looking into the 21st century, and seeing everyone using cell phones.
All I can say is "Well done"
Gina
This is correct.
The goal of my design was an air cooling system.
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