What type capacitor works best for 100KHz?

[be80be]

I just wonder if it's like welding you better unhook the battery or haft the electronics stop working.

 

[gary350]

Be aware, many box capacitors are the same rolled capacitors inside. You need to look at the specs of the individual capacitor.

Yes I know some are flat wound & some are circle wound. I bought 8 of these I will see how well they work when I do the smoke test. LOL. I can also check capacitor inductance with my meter.

 

[unclejed613]

His cap only going to be something like .06u adding 8 just increases the voltage voltage they can handle but it lowers capacitance.
Looks fun to play with tho

the caps are in parallel, not series. capacitances add in series.

Be aware, many box capacitors are the same rolled capacitors inside. You need to look at the specs of the individual capacitor.

even the tubular mylar caps have a conductive layer at the ends, which eliminates the inductance of the rolled layers. "Application of metallic contact layer ("schoopage") — The projecting end electrodes are covered with a liquefied contact metal such as (tin, zinc or aluminum), which is sprayed with compressed air on both lateral ends of the winding. This metallizing process is named schoopage after Swiss engineer **broken link removed**, who invented a combustion spray application for tin and lead.[7]"

now, there may be real cheap caps that don't do the metallization, and just bond a wire to the foils, but any reputable manufacturer has the metalization layer at the ends of the cap.

considering what the OP is trying to accomplish, the best caps for this job will be Illinois Capacitor PHB series caps. it's the type of application they are made for.

https://www.illinoiscapacitor.com/pdf/seriesDocuments/PHB series.pdf

 

[DerStrom8]

the caps are in parallel, not series. capacitances add in series.

You sure about that?

 

[be80be]

Nope it becomes less in series The big thing here is amp's by adding in parallel you can let more amp's flow but what happens is not all cap's are the same even the solder can cause problems you'll pop a cap a good set of bolt in caps may work the best but a bolt in cap can be had that would do the job too being with.......

**broken link removed**

 

[gary350]

You sure about that?

I remember this from college and found a video online.

 

[be80be]

You want the amps the cap's i post can handle lots of amps.

 

[unclejed613]

You sure about that?

wow, tha, wasn't was an oops, wasn't it .... you know what i mean... correction: caps add in parallel.

btw, note to moderators: i miss the original animated smilies that were on this board years ago...

 

[DerStrom8]

btw, note to moderators: i miss the original animated smilies that were on this board years ago...

Unfortunately the smilies are part of the site code and the moderators do not have access to that. You'll have to take this up with the admins (i.e. dmiyares ).

 

[Nigel Goodwin]

Hi Gary, why don't you just try one of these to play with?

https://www.banggood.com/Low-ZVS-12...duction-Heating-Machine-Module-p-1038472.html

 

[unclejed613]

interesting, but no mention of the operating frequency. in the operating instructions, they recommend connecting the tubing to a water pump and pumping water through the coil.

 

[Nigel Goodwin]

interesting, but no mention of the operating frequency. in the operating instructions, they recommend connecting the tubing to a water pump and pumping water through the coil.

You can't grumble at the price though, and anything of a similar size and power is probably going to need water cooling.

For the price it's worth him trying one to see how it does, much easier than trying to make one (at much more expense as well) and killing buckets full of components

 

[be80be]

What I don't get is the one that is $400 and you can hold in your hand the bolt buster just dont look like is could work.

 

[unclejed613]

actually, that probably does work. often, when a nut is frozen on a bolt, you heat it up so it expands a little. doesn't need to be heated red hot.

 

[be80be]

actually, that probably does work. often, when a nut is frozen on a bolt, you heat it up so it expands a little. doesn't need to be heated red hot.

I been heating bolts for year like for the last 40. I just don't see the little thing having that much power and be so small.

I like to see a tear-down on that baby.

 

[unclejed613]

it probably is AC powered, no way that thing runs on batteries. other than that i can see a problem already. the screws that hold the coil wires in place go into the heat sink. how long before the aluminum strips out? although, for $400, there could be steel inserts in the aluminum.

 

[gary350]

When dealing with a rusty nut stuck to a rusty bolt muriatic acid is best because it will remove the rust from the steel. But when your dealing with a bolt stuck in an aluminum engine block you can not put muriatic acid on aluminum. Heat will soften lock tight for removing a bolt. D alkaline batteries I have tested put out 8 amps and some rechargeable D batteries put out 50 amps.

 

[Nigel Goodwin]

D alkaline batteries I have tested put out 8 amps and some rechargeable D batteries put out 50 amps.

Funnily enough I was looking at D cells the other day - as (in my new job) I was repairing a couple of items (both the same) that take 12 of the Alkaline versions!.

Part of my job (the major part) is designing products to improve what's available, or try and develop new items entirely, and as I could easily greatly improve this unit and make it much smaller and cheaper I looked up specs on different batteries. Obviously I would prefer re-chargeable, as small as possible, and hopefully longer lasting. I was staggered to find that Alkaline D cells are really pretty impressive, and my dreams of a handful of NiMh or Li-ion beating them were dashed

Not to be beaten, we're now approaching the people who use the units, to see how long the batteries last, and if having shorter lived re-chargeable ones (that you could recharge either from mains or in the van) would be acceptable. We're also like to know how much the existing units cost, and what sort of market there might be for an improved and lower cost unit.

 

[be80be]

You can get a Rechargeable Alkaline

 

[unclejed613]

just on the chance that somebody might find this thread while looking up induction heating, or maybe the OP drops back in for another look, i found a pair of books on induction heating that was written for training classes for foundry workers. the books are in the same pictorial/ informational format that was used for many military electronics training courses during WWII. the books are very descriptive of induction heating precesses, and even teach the basic math needed for understanding induction heating. in volume 2 of the texts, a lot of good information is laid out on types of induction heating equipment, including motor-generator, vacuum/gas tube power oscillators, spark gap oscillators, etc... basically volume 1 is mainly about the physics and basics of induction heating, and volume 2 is more about the electronics, mechanics, and equipment. i had these books when i was a teenager. when this subject came up in this forum, i remembered those books, but i couldn't find them right away online. https://catalog.hathitrust.org/Record/007471770

one thing i found interesting in volume 2 was the arrangement of a power oscillator tank circuit with a tank coil and a work coil. also the description of how the tank circuit works as part of the heater coil circuit. the RF current coming into the tank circuit is 300A for instance, but the circulating current at resonance (with the workpiece in the coil) in the tank circuit is around 1400A.