Looking for heater element controller

[avz]

Hi,
I would like to make a heater (230vac cooker) element controller, so that I'll be able to control the heat that it produces. I would like it to enable a long cooking time on a low heat. I've ordered a 4000W "dimmer" controller from Aliexpress (it's based on the BTA41600B scr) but unfortunately it's has a very narrow working range on the potentiometer's travel, only toward the "max" end of the travel, so I'm looking for a circuit diagram that will have a more "linear" range to enable a better control.
Thanx.

 

[Nigel Goodwin]

That's not really the way to do it - it's normal to use burst-fire control which is far more efficient - and the very long thermal inertia means it's more than effective enough. Normal power control for a cooker element is really crude burst fire (on for 10 secs off for 20 secs etc.), and doing it on a per mains cycle basis would be efficient and accurate.

Presumably the dimmer is intended for lighting?.

 

[avz]

According to the seller, it's kind of multi purpose, to control lighting, motor speed and heater. unfortunately (for me, at least) it's not quite so.
If I understand right, you are suggesting a sort of timer that it's duty cycle will control the temperature. the timer can be done with a 555 turns on and off a triac. if so, do you know if such an application exists already?

 

[Nigel Goodwin]

According to the seller, it's kind of multi purpose, to control lighting, motor speed and heater. unfortunately (for me, at least) it's not quite so.
If I understand right, you are suggesting a sort of timer that it's duty cycle will control the temperature. the timer can be done with a 555 turns on and off a triac. if so, do you know if such an application exists already?

I would imagine the dimmer is designed for incandescent lamps, so the position of the pot is designed to give good control for lamps.

As for burst fire, you really need it more complicated than a 555 as you want the switching to occur at the zero crossing points to avoid interference.

In the distant past it was done in hardware (and there may have been 555 examples?), but now a PIC or similar would do the job with very few components and a little software - it would also be trivial to calibrate it if required, to give a nice linear control.

 

[avz]

Thanx for your reply. do you know if and where I can find such an application? I don't have any experience with PIC's, so I don't think it will be practical for me to design it.

 

[Wp100]

Sounds like you need something alone these lines which use methods like Nigel mentions.
https://www.instructables.com/Arduino-Sous-Vide-Cooker/
https://learn.adafruit.com/sous-vide-powered-by-arduino-the-sous-viduino/materials

if you search "Sous Vide" you will find plenty of similar examples but be very careful as you are dealing with heavy current mains electricity !

 

[rfranzk]

I recently used one of these for a project and it works great. They are not terrible expensive and would only require that you find a voltage or current input to control.