3 phase power, elements and wiring controlers

edited June 2013 in Accessories

Hi all, just a quick question for the sparkies or elec guys out there. In Australia on normal 240v + 3 phase power I'm about to grab a few parts and chuck a keg into use as my new boiler. I'm going to step up from 2" stuff to 4" unit. I know that std power points are ok with 2400w elements, some tend to push the to 3600w, I've pushed mine to 2 elements 1800w+2400w (4200w) we all know thats far too much for normal power points, yes it gets hot quick but so does the cable, power point and my nerves, so I tend to use one or the other with no controler. I have in my shed a sub-station power board that has 3 phase connected, I understand I can run 3 seperate power points on each phase with 10 or 15 amps, perhaps up to 3600w each. I could do this and have a ssr power contoler for each element, and have 3 elements for super fast heat up times, fast stripping etc, then wind back to 1 element for normal runs. Is there a better option to simply use the 3 phase generic either delta or star configurations, and what would I do for actual power control; 3 controls on each phase or is there a 3 phase ssr setup? Thanks in advance for your opinions and suggestions.

Fadge

Comments

  • You can buy a 3 phase SSR cheaply from ebay, and use your standard controller for all 3 elements, then have either a 2 phase switch or 2x single phase switches to independently turn off the 2 elements. I'd just run them in a star configuration. ie. phase to neutral for each element.

    Another option is to use a PID or temp controller, and use this to control 2x elements. When your boiler reaches a certain temp, have the PID/Temp controller turn these two elements off, and let your 3rd element run your still as normal.

  • Thanks, have looked at the ssr 3 phase units and looks like that is the simplest way. Use our common single ssr unit to control the 3 phase unit via ac voltage input. Addition of separate switching for each phase-elements would just offer better overall management without costing much and basic wiring required. One control box 3 outputs, all switchable on or off, 3 phase energy capacity. Thanks, and willing to have have others thoughts on this. Fadge

  • @fadge said: Use our common single ssr unit to control the 3 (Ø) phase unit via ac voltage input.

    I can't say whether this would work or not, as these types of SSR's usually have zero crossing built in. You "may" not get reliable conduction with your 3 phase SSR being controlled by the 1 Ø SSR?, but I don't know - another Sparky will hopefully clarify this.

    What are you using to control your SSR now? You should be able to "piggy back" another set of leads off the 1 Ø SSR to control the 3 Ø SSR.

  • edited June 2013

    3 phase in the shed. lucky man. what is the current rating you have available?

    Switching each element is a quick & easy way to obtain basic power control. Instead of installing 3 single phase elements, consider using 3 phase elements ie you get 3 elements in the 1 bobbin. have a look them on p21 of this manual.

    You can get 3 phase SSR's off ebay which will drive all 3 elements. you just need to get 1 with the control signal input that matches what you are using to control with. Don't forget you will need a decent heat sink for the SSR.

    I have a single phase SSR that i can drive at 100%, via PID control or use a simple PWM circuit to manually adjust output from 5-95%. Details are posted over on AD.

    have a chat to Rob at Romar Elements he is a good guy & does custom element builds at a reasonable price.

  • Guys thanks for the feedback, @crozdog looked at your setup and I'd have to say thats the perfect way to go, your control box looks great. I'm needing to get my sparky around to confirm the actual safe load on the 3 phase, and place a new outlet/switch right beside my sub-board. My shed was a mechanics garage, did have 3 phase compresser, hoist, air-con etc (main switch is 63amp rated) Unsure of the real capacity, the main house power board has a 3 phase 6kw air con/heater connected, so I'd be wary of adding too much on my sub-board if they ever run at the same time.

    @Philter after reading the advice above I was hoping to use a simple diy ssr setup to run (piggyback) into a 3phase ssr, but the safety of having a PID controler to turn off elements when over a preset temp is smart. I was assuming that we all use a voltage or resistive "knob" to control SSR and in turn the power going into the heating units, as a known value, the heat just happens to match the inputs. If using a temp controller to adjust the SSR is it much the same thing? or will it achieve the same result? or does it act like a thermastat- not good for distiiling, too much off/on stuff?

    I do have thoughts of filling the keg, turn everything on flat out with maybe 10,000w of power, then getting sidetracked and shit will happen.

    My control box should be wall mounted with indicator lights and switches for each element, volt/amp meter etc. A over temp alarm seems to be a good idea, one that can be heard from the house, 20m distance.

    I've held back on placing my order with punkin untill I sort out element type and qty, then what ferurules etc I'll need.

    Did not even think about using a combined element setup, one plug, one cable etc. I'm about to email Rob about a 3 phase / 3 element setup to see if it is workable. I'd be happy with a combo 3 x 2400w-3600w unit. 7200w-10,800w. Should be fast heating and allow my hobby to grow as we all know it will. Goodbye 2".

    Fadge

  • @fadge the psr25/40 phase angle controllers use a pot to adjust the proportion of the waveform sent to the load. I use a "pulse width modulator" circuit to achieve the same result using a different technique ie adjust resistance which adjusts PWM on % which drives ssr. A relay (be it solid state or coil based) is a device used to control a high current/power circuit using a low power circuit. I do not understand how you would use a single phase ssr to control a 3 phase ssr....

    I mainly use my PID for temp monitoring rather than control - but do use it to control herms for the brewery.

    I strongly suggest you get your sparky heavily involved if you don't have a background in moving electrons & controlling them...give him a briefing on what it is you want to achieve & details as to how others such as myself have achieved power control.

    Don't forget you should never leave your still unattended. If you are with it, there is no need for 110dB alarms!

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