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Adding an SCR to Pi Brick

Posted: Tue Apr 11, 2023 2:27 pm
by Chuckg
Bernard,

I am building out my Pi for a BIAB system using crafthardware.de equipment based of your PI Brick blog and YouTube. One change is the need to reduce power to the heat to support the steam condenser. Here is the SCR I got:

SCR Electronic Voltage Regulator Governeur 4000 W Digital Speed Control Dimmer Thermostat AC 220 V Motor Speed Controller https://amzn.eu/d/8MFgRsI

It appears to be the component in the device recommended on crafthardware.de.

Can confirm my setup for an AC regulator?

Live (L) Brown: AC In1 -> Relay (30A to support 14A heater) -> SCR -> AC Out1.

Neutral (N) Blue: AC In1 -> SCR -> AC Out1.

Ground (G) Yellow/Green: AC In1 -> AC Out1.

Once I finish and don’t burn my apartment down, I will post a diagram similar to you blog here if you would like.

Thanks,
Chuckg

Re: Adding an SCR to Pi Brick

Posted: Tue Apr 11, 2023 2:42 pm
by Bernhard
Hey Chuckg,

unfortunately, I cannot say anything about the linked Thermostat. I know a lot of people are using this one: https://www.regler-shop.com/produkte/#c ... 7694634954 which is a little more expensive but looks way more trustworthy to me.

Anyhow: I think it's important to connect the SCR to the output of the Brick - otherwise it will probably loose connection. So Socket (wall) => Brick => SCR => Boiling heating.

Also: Be advised, that there will be some "Soft-PWM" allowing you to configure the boiling power percentage. 90% meaning 9s 100% on, 1s 90% off. Might be a PRO feature, though because this will cause higher load on my backend unless I make a firmware change which would require a firmware upgrade.

Pro Tip: Do it not inside your house, so you cannot burn it down. Jokes aside: Be carefull and consult an expert if in doubt!

Cheers,
Bernhard.

Re: Adding an SCR to Pi Brick

Posted: Tue Apr 11, 2023 3:28 pm
by Chuckg
The part I am using looks exactly like the UI on the no-shutoff version of the device from your link. It is the one Doug/Crafthardware recommends. I should have been clearer. The SCR is inside my Pi brick case. So I will control the relay from the pi4. I have:

In a single lock version of cabinet (from blog)
Pi4
7” display (from blog)
1 x 2.5A/60W out LED transformer for AC to DC
1 x DC regulator (from blog)
1 x 3 way switch (from blog)
1 x 2 channel relay (from blog)
3 x C20 In
2 x Schuko out
1 x D18B20 port in
1 x DC port out
1 x 30A 2 Channel Relay (for 14A heating element)
1 x 4000W 240V SCR ( previously linked)

Thanks,
Chuck