Alternative popper mod suggestions

[Bill]

Re: Alternative popper mod suggestions

Yes mate, I knew what you meant but for non-electrical people it is very confusing....

Mal.

Ok. Sorry, I misinterpreted what you said earlier. I thought you were arguing that there was only 1 element, instead of 2 - that your poppers didnt have the extra middle element. Obviously there are 2 elements.

But I now see that what you were really arguing about was how the fan is wired up in standard form. I dont disagree with you. Thats not what I was talking about, as it doesnt concern me. Since were disconnecting the fan and powering it separately, how the fan was wired as standard isnt really relevant to what were doing here.

[conan.obrien]

Re: Alternative popper mod suggestions

Hey thanks everyone for your advice and ideas. Im sitting here with one of my first coffees in the cup. :

Im no electronics expert but from what Ive read the fan and heater circuits are linked.
Your idea may do something to the heater that you dont want it to.

Youre right Thundergod, there will be a side effect, with the fan jumped up to 24V it will reduce the heating
power by between 3% and 6% (depending on how much of the heat generated in the new resistors ends up in the airflow). But that will help a little with operation slowdown.

adding resistance will lower the voltage across the motor you want to lower the heater resistance so more voltage is across the motor, it basically a voltage divider with the heater running on 220 and the motor on the remainder about 20V,

Increasing the smaller resistor definitely increases the voltage across the fan. Using your numbers and the voltage calculator you suggested (thanks, Ill use that to check the results of my scribbles) increasing the small resistor from 4R to 5R increases the voltage from 20V to 24.5V.

Potentiometer control of the fan speed is not the way to go, far better to split from the voltage divider that are the heating element sections and use a suitably rated transformer driven by an electronic ceiling fan controller.

Thanks Mal, youre right about my potentiometer plan not being the way to go, it would have given me a weird irregular response when I turned the knob.
I guess its just an aesthetic thing (safety too maybe), but Id like to do a modification that fits within the unit rather than having wires running around the place. Id also prefer not to hack into the case, Id rather do a proper job modifying the electricals and sealing it back up than opening up the bit with live lethal wires and leaving it open. That said, I might totally replace the original case with something nice and enclosed but with plenty of vents.
So youve got me thinking of a new plan. Why not put in a constant 1R5, 40W resistor in line with the small resistor element to increase fan voltage (instead of the transformer) and then put a ceiling fan controller in the resulting 25V AC part of the circuit? Id have this new knob sticking out the side of the original case so it looks like it was built that way.
Only problems are Ive lost a few percent of heating power and I cant switch off the element to use the popper to cool the beans. How important are those two things?
Thanks again,
Conan

[conan.obrien]

Re: Alternative popper mod suggestions

To run the main outer heater element only, all you have to do is connect A to one side of 240V and B to the other side of 240V. Current then only flows between A and B, ie. both ends of the outer main heater element. As we leave C unconnected, no current flows between B and C, ie. the resistor wire for the fan does nothing.

Its amazing how similar all these poppers are (except for Dans old one but even it is only slightly different).
Have many people done this particular modification that Bills talking about, leaving the smaller element out of the circuit? The thing is it reduces the total resistance by about 10% so it must increase the current (and therefore power) by about 10%.
Do these things burn out if you do that?

Conan

[conan.obrien]

Re: Alternative popper mod suggestions

what about separating the two: Fan <-> heat and using a couple of phase angle controllers or triac based power controllers ?

Thanks Maheel.
Might be the way to go. Ill have to do a bit of homework on that. Are those things the same as the ceiling fan controllers people are talking about? How many $$?

[Firepower]

Re: Alternative popper mod suggestions


Hes talking about internal vent holes in the metal wall, I read many about more vent holes in the outer case, side and bottom. the photos in the link explain better. may be i missed enlarging the internal vent holes in posts here.

[mrseca]

Re: Alternative popper mod suggestions

This has turned into quite a technical discussion.
My disclaimer - Do not attempt to do anything I have mentioned unless you are competent to do so safely.
On with the show.
I have attached my dodgy schematic of my popper, missing a few capacitors that are not important for this topic. For the record, the fan voltage control is totally different to mals and the majority of others by the sounds of things.

My popper is wired exactly as bill writes in his first post.

Please disregard my posts if your popper is not like mine.
I am an electronics hobbyist with a bit of electrical training and a little common sense. (stress little).

Dan.

[Thundergod]

Re: Alternative popper mod suggestions

Hes talking about internal vent holes in the metal wall, I read many about more vent holes in the outer case, side and bottom. the photos in the link explain better. may be i missed enlarging the internal vent holes in posts here.

Sorry, I misunderstood.

However, I fail to see how that addresses the OPs problem.
His problem is that the popper is currently running TOO HOT.

The article clearly states that opening up the roast chamber holes will allow more HOT air in.

[Dimal]

Re: Alternative popper mod suggestions

I have attached my dodgy schematic of my popper

Have never come across that design before Dan. Just shows how careful youve got to be when proffering electrical advice... Cant be too careful no matter what modifications are planned

Mal.

[Firepower]

Re: Alternative popper mod suggestions

I dont know , I just high lighting what has been done so other here can try and give feedback.

[Bill]

Re: Alternative popper mod suggestions

what about separating the two: Fan <-> heat and using a couple of phase angle controllers or triac based power controllers ?

Thanks Maheel.
Might be the way to go. Ill have to do a bit of homework on that. Are those things the same as the ceiling fan controllers people are talking about? How many $$?

An ordinary ceiling fan controller works (in conjunction with a transformer) for the fan control. For heat control youd need something like a high power light dimmer - I used a 2000W one, but you shouldnt need one rated quite that high. The poppers are usually rated around 1100-1200W, so something rated to that power should do.

[maheel]

Re: Alternative popper mod suggestions

Thanks Maheel.
Might be the way to go. Ill have to do a bit of homework on that. Are those things the same as the ceiling fan controllers people are talking about? How many $$?

you "can" build your own triac based ones for about $10, they are better than fan controllers as they have a nearly infinite range of control (depending on resister selection etc) You have to do your own solder work (pcb boards etc)

phase angle cost a bit more depending on if you get a "kit" or ready made. (about $50 to $100)  but you also dont have to do the solder work and again gives you "infinite" range of power control. i actually thought that they might make an interesting mod to a KKTO heating system so there would be no cycling


i have never seen a 2000w light dimmer (actually PMed Bill about it), and the normal ones only run about 600w i thought. Triac and PA can handle any amp / watts you want with the right part specs

if you look at RS-online, and search for PSR-25 and look at the
the range of alternatives.

they are all 240v so get a sparky / electronics mate to build and check for safety etc  

i have a PSR-25, i also built a working prototype home made triac one but my solder is crap so it looked super dodgy... rather than my normal dodgy
i can supply a diagram if anyone is interested  on the triac design

Leeham

[conan.obrien]

Re: Alternative popper mod suggestions

Looks good Maheel, Id like to see a diagram if you feel like putting one up. I might do that when I do the final version of my popper.
What do I need to take apart to find triacs that can handle power?

For now Im gonna crack that power control nut with a beautiful old sledgehammer in the form of an big old variac my grandfather gave me. I just have to check the current rating on it when I get it out of storage. (btw I saw a 5A variac on a popular auction site for pickup in footscray if anyone wants big-is-beautiful power control).

Another cheap option: I stumbled accross infinite switches while researching phase angle control. They control the current with a bimetalic strip inside the switch that gets hot when the current flows. They are in electric stoves like you see in skips every other day, prob is you need to get exactly the right current rating because you cant change them easily by just adding resistors.

[Bill]

Re: Alternative popper mod suggestions

i have never seen a 2000w light dimmer (actually PMed Bill about it), and the normal ones only run about 600w i thought.

I wasnt able to find such a high power one either, within Australia, but was able to source one online from an electronics supplier in the UK. Can get ones up to 4000W from the same supplier.

[maheel]

Re: Alternative popper mod suggestions

Ok this is the diagram (simple picture) traic based power controller

the 1st one i built did not have the 1M resistor and was not 0 - 100% linear. it did range from around 140v to 240v control i was then advised to add the 1M and it should help. I am not sure if i built and tested it with the 1M res

The BTA26-600B TRIAC could then handle 26 amps, way more than what i wanted at about 2500w. so you could choose a lower amp triac.



the BTA26-600B TRIAC (or any triac) would have to be mounted to a heat sink or it would quickly blow blue smoke... i used a PC heatsink and fan. You would of course also need to earth it correctly and safely. no earth is shown !! but needed !!

Isolated triacs are very important as some are not !!! and make the heatsink live !!!!

there is a 50page thread about power controllers on "homedistiller.org" where more information can be seen on this diagram at about page 30..... other ideas are in the thread

other smarter than me people here might have some input  

disclaimer, this post is for information only, anyone attempting to build this should consider the risks. no responsibility taken by me or anyone

[hazbean]

Re: Alternative popper mod suggestions

Just a note re Bills post above (#27) about dimmers. Earlier this year I needed a 1000W dimmer for heatimg control on my Gene. The only Aus one I could find was $160. So I imported a Varilight dimmer from the UK. This played up at first, but an email exchange with the engineers at Varilight sorted out how to fix it. Basically the heatsinking needed attention. What I did was disassemble it, apply plenty of heatsink compound at appropriate places, especially the contact area between the triac and the supplied heatsinking; then added additional heatsinking, comprising aluminium sheet bent into an S-shape and with finned PC heatsink blocks attached. I left room in my enclosure for a fan, but that hasnt been needed, it has worked fine ever since. With the additional heatsink properly installed, the dimmer easily handles the 1200W of the Gene. Nonetheless, had I known when I bought it that they had a 1500W version for not much more, I may well have bought it (in that design, the triac is separated out from the other components). Anyway, clearly heatsink design is a key aspect of these higher power dimmers (that might be why the Aus designed one is a lot more expensive).