Review my heater controller (Sanity Check)

[tiramisu]

After a fair bit of reading, I've got a plan.
It may not be a good plan. I'd appreciate those of you with knowledge of Electropixies to give this an eyeball for correctness and possible improvements.

Thanks,
t

[Salt Must Flow]

It all looks right to me. I have seen people run a ground to their heatsink when using plastic enclosures. I don't know if you should or would benefit from running a ground to the SCR. I've never used an SCR, but I don't see how it could hurt by grounding it.

[elbono]

Get a good crimp tool for your spade connectors. It's close to impossible to get a proper crimp otherwise. Klein makes a good one www.kleintools.com/catalog/combination- ... -terminals it won't open until the crimp is complete.

Your L5-15 connectors are rated for 15 amps which is fine as long as you don't run 20 amps through them. I use L14-30 on my 240v controller, you wouldn't need to change this later if you upgrade to 240v with them. https://www.hubbell.com/wiringdevice-ke ... /p/1640169

Make sure you plug this into a GFCI and you're good.

What are the details on your meter? I can't find a panel mount I think will be accurate so I use my true rms multimeter until I do.

[shadylane]

I'd recommend soldering the spade connectors to the wires.
Also use an AC powered fan to do away with the 12v supply.

[elbono]

use an AC powered fan to do away with the 12v supply.

That will definitely make your life easier. Here's the 120/240 fan I used. My heatsink stays well under 40C with it.

[Yummyrum]

The meter will invariably go up in smoke if you have the voltage leads wired to the output side .

Connect it to the input . Yes it will then not measure the voltage to the element , but it won’t go poof either .
Also , as Elbono said , unless it reads true RMS , it won’t give you an accurate reading anyway .

It will still give you a rough current reading that you can use fir future reference.

[elbono]

The meter will invariably go up in smoke if you have the voltage leads wired to the output side .

There are some cheap ones that get power and signal on the same terminals. Some with a note they will melt if used on an inverter not sure if they will actually melt but I'll bet they're definitely not accurate https://a.co/d/bR1jBYG for the non sparky's out there the scr/power controllers we use give the same waveforms as inverters.

[tiramisu]

Thanks for your insights...

Ground

Ground to load seems to be the general recommendation.

Spade Connectors

Solder - Check.

Fan

AC Fan - Not easy finding a 30mm ac fan that has reasonable jam.

I ordered 2 of these
https://www.aliexpress.com/item/3284640 ... 1802v1Ugji

AC / DC 12V Power

I ordered 1 of these widgets

Plugs

I have 30 Amp plugs, a 50-foot roll of 10 gauge 4 wire tech cable, and a 5kw element in the garage. I will likely order the 50 Amp D-Squared Spa Panel for GFCI for 220 and the b-in-law is a wire puller so I will get babysitting for that project.

Female-Female connectors on the Box. I gave it a little thought but then I also need to make a custom male/male extension cord AND someone said it's bad luck if your input has an inny. (Still a very tempting way of making the box cleaner - I may add this when I 220).


Amp/Volt Meter

I have an el-cheapo, this is mostly eye candy for the box. Although, it's nice to know if the box is doing weird shit. What would I need to get that would simply cook itself? I don't grok "True RMS"

https://www.aliexpress.com/item/1005002 ... 1802v1Ugji

Thanks again for your help. I appreciate it.

[Yummyrum]

Heres a good topic about True RMS meters .
viewtopic.php?p=7683511#p7683511

Heres just one of the many discussions about self powered meters “burning out “ when connected to the output of an SCR type controller .

viewtopic.php?t=56032

[shadylane]

I've used several cheap digital meters and all of them eventually failed.
The most dependable option so far has been a simple analog voltmeter.
I used a good quality RMS meter to measure everything, then made a scale for the analog voltmeter that is calibrated in watts. It's not pretty and is only accurate for that heater but it's been working for years.

[kennstminet]

I'm using this cheap Wattmeter since years at the output side of a SCR Power controller and never had an issue.
https://www.ebay.de/itm/314751401269?mk ... media=COPY
It is able to measure the voltage and the power quite accurate, even with the non sinus wave of the power controller.

[tiramisu]

I'm using this cheap Wattmeter since years at the output side of a SCR Power controller and never had an issue.
https://www.ebay.de/itm/314751401269?mk ... media=COPY
It is able to measure the voltage and the power quite accurate, even with the non sinus wave of the power controller.

Thanks for the tip. I may order one just to have in inventory for when the current one dies.

[Salt Must Flow]

Something about using SCRs never sat right with me. I've heard stories about them failing to the point where people said, buy two for if/when. I've also heard stories about them lasting a long time and never failed people. I never knew they didn't 'play right' with watt meters though.

For my first controller, I bought Still Dragon DIY Controller parts and one of their SSVR. I used a different enclosure, added a fan and some other components. I don't know what the cost is compared to a SCR build, but it worked fine for me.

Later I replaced the SSVR with a SSR and upgraded to the Auber DSPR400. With this controller, I didn't need a Watt meter at all. The screen reads % power on it. It doesn't take, but a moment to calculate how many watts it's running at. It also uses a RTD sensor and reads temp in 1/10th degree resolution which is very handy. It has user set temp alarms and does a LOT of cool stuff that I'll probably never use. It costs more, but you know what they say, "buy once cry once". Since then I've built a 2nd Auber controller too. They're just that great.

If you know you want just a basic variable controller, it's pretty hard to beat the Still Dragon parts, but I think that the Auber DSPR1 has it licked. It's also a very basic variable controller unit that uses a SSR and heatsink. I'd take a close look at that one too!

[elbono]

There's all kinds of bad things that can happen with that cord.

What you need is an "inlet".

https://www.hubbell.com/hubbell/en/Prod ... /p/1640474

[jonnys_spirit]

My 240V power controller is hard-wired to a male dryer plug. I just can't use the 30A dryer outlet when I'm running the still which is fine by me. I recently got my sub panel and main disconnect replaced so now I can hardwire a 30A (or two) circuit from the panel to a junction box where my primary controller and a secondary controller can be hard wired. The connection from the power controller to the heating element is a twistlock.

The Hubbell "inlet connector" that elbono linked would be another safe alternative.

Hardwiring it to a dryer cable was cheaper for me and I could pick up all the parts at HD.

Some folks may also insist on a GFCI circuit which would also increase your safety margin for WTF moments...

Cheers!
-j

[elbono]

Some folks may also insist on a GFCI circuit which would also increase your safety margin for WTF moments..

Guilty as charged. They're not cheap but worth every penny in my opinion. They can be installed in the panel. I think code in the US requires them on laundry circuits nowadays.

$75 on Amazon. Siemens QF230A 30 Amp, 2 Pole, 120/240V Ground Fault Circuit Interrupter with Self Test and Lockout Feature, Cardboard Packaging , Black https://a.co/d/8Y6nr9k