Watercooling

[flyingperson23]

After running my big coil, I noticed lots of thermal warping and discoloration on the inner turns of the primary. I've never messed with watercooling before, but I'm told it can be really annoying, especially concerning long term storage and corrosion prevention. For those of you with watercooled coils, do you recommend it? Or should I just put a box fan next to the primary

[Benjamin Lockhart]

I also got some discoloration on the inner turns of my big coil before adding watercooling. I definitely recommend it! I did try running compressed air into the inside turn but it did almost nothing. Water is the way to go. Maybe don't use an aluminum radiator due to the dissimilar metals.

[flyingperson23]

Forgot to add those before - this all happened over the course of maybe an hour

[davekni]

Or should I just put a box fan next to the primary

I did try running compressed air into the inside turn but it did almost nothing.

Haven't tried compressed air, but it would be difficult to get enough air flow to be effective.  I did add a pair of 120mm fans blowing up at my DRSSTC primary from opposite sides.  Definitely helps, though probably not as much as water cooling would.  Might be sufficient if your mechanical design allows for air flow from below primary.  I added copper shielding over fan motors and initial bit of lead wiring to prevent internal motor electronics from getting confused by primary magnetic field.  (My primary is litz wire, so no reasonable water cooling option.)

[Michelle_]

I'm assuming by "water cooling" you mean some kind of coolant solution? I would recommend finding coolant that is compatible with copper as well as your radiator, it will improve the heat capacity and limit corrosion and therefore maintenance intervals. It's actually not difficult to get/make flared fittings for copper tubes but as for what effect it has on the electrical properties I can't say.

[Benjamin Lockhart]

No, I'm just using straight tap water. The difference in primary coil temperature is tremendous vs no cooling.

[Michelle_]

No, I'm just using straight tap water. The difference in primary coil temperature is tremendous vs no cooling.

You can do that but there's a reason people don't use tap water in cooling systems in cars in machines, I think you would get better performance and less corrosion using coolant or even distilled water. Just a suggestion but for this application I don't know how much it matters.

[flyingperson23]

I haven't heard of anyone using coolant, just tap or distilled water. Corrosion shouldn't be an issue with a copper radiator.

[Hydron]

if you run open loop water cooling from a garden hose or something, surely you can just blow out any remaining water with compressed air or something once done and just ignore any corrosion? Not like many coils run for substantial amounts of time.

[Michelle_]

if you run open loop water cooling from a garden hose or something, surely you can just blow out any remaining water with compressed air or something once done and just ignore any corrosion? Not like many coils run for substantial amounts of time.

You can do it lol, don't mind me I'm an engineer and I've worked on cooling systems, I agree with you guys that for this application corrosion and performance of the heat transfer aren't going to be critical, but over time you could possibly get pitting or residue.

[Hydron]

Oh for sure not saying that's the right way to do it, more thinking about what the quick and dirty minimal modification options are for testing at least.

Keeping corrosion and conductivity down may be pretty important for closed loop systems given the voltage on the primary. Having a long enough pipe is probably sufficient for open loop.

[Michelle_]

Oh for sure not saying that's the right way to do it, more thinking about what the quick and dirty minimal modification options are for testing at least.

Keeping corrosion and conductivity down may be pretty important for closed loop systems given the voltage on the primary. Having a long enough pipe is probably sufficient for open loop.

Yeah that would work well for seeing if it works or not and wouldn't cause long term damage. For a closed loop system I would recommend something like an automotive transmission cooler with a 12v fan and a small 12v water pump, and liquid dielectric coolant (often used for cooling battery systems, if it leaks it won't do anything to your electronics unless it's gotten highly contaminated). Some of these coolants are actually used for immersion so if you really wanted to you could probably plumb through the primary into a sealed enclosure with all of the electronics driving the coil in the closed system and cool all of it, I know that sounds crazy and such a system would probably cost as much as people's entire tesla coil builds lol.

[Mads Barnkob]

I remember Steve Ward telling about his water cooling experiences.

- Distilled water will get contaminated pretty fast, there is no real advantage over tap water.
- Tap water in a bucket, with a 230VAC pump in, has a sufficiently high enough impedance to run through the primary circuit, without any issues.
- A normal sized bucket of water will last long enough for playing some MIDI files, before being luke warm to the touch.
- You can easily change bucket, not so easy in closed loop.

My own thoughts
- You can blow compressed air through when done, to avoid corrosion, maybe add a few drops of oil.