DIY Power Controller

BIGBIRD123

Can you tell me if this will work as a voltmeter. I like the fact it requires no additional electricity. Also, I am thinking about wiring in a door bell transformer to power the 12vdc fan. Any comments?

AC Dual Display 299V 50A Amp Volt LED Panel Combo Meter With Current Transformer @ eBay

BB

Duck0fDeath

Better prices here

olddog

@BIGBIRD123, they work very well unless you are using a PWM controller which has a pulse output.

OD

Duck0fDeath

So the Toroid amp meters don't work with the SSR outputs?

NineInchNails

oldog will it work with the Still Dragon DIY Controller parts? I recently ordered one of these and it should arrive soon.

olddog

Yes it will work fine with the SD controller

NineInchNails

Thanks oldog. I get it now. Those volt/amp meters won't work with PWM controllers like these.

olddog

Anything with a pulse output will make the readout fluctuate. The SD controller is a constant output which is fine.

OD

Duck0fDeath

Thanks OD :)

fadge

@NineInchNails said: Thanks oldog. I get it now. Those volt/amp meters won't work with PWM controllers like these.

FYI

Just the unit I used to build my controller, added a fan and lights, combo voltage/amp meter like this

It seems to work fine, the voltage and amps read steady, in fact in one of my videos its shown working.

I may have just been lucky ? I've only built one controller box so far, but have parts for a second one. Next one is inspired by OD and the PID's semi/fully automatic controlling setup.

This is perhaps drifting a little off topic as its all about the SD DIY kit ?

Cheers

Fadge

moscca

I bought one of these for my SD DIY temp controller.

Digital AC 80~300V 100A Ammeter Voltmeter LED Panel Meter Transformer 110V 220V

I use a 6000 w element and have 2 X 110 V. At very lower volt it reads the same as my Fluke, but when I increase power the difference become bigger and bigger. When i go to full power they meet again. Not happy with it.

captainshooch

@moscca on the leg that is controlled by the SSR, did you wire the voltmeter wire before or after the SSR?

moscca

@captainshooch said: moscca on the leg that is controlled by the SSR, did you wire the voltmeter wire before or after the SSR?

After te SSR, I even put it on the element connection, but there was no difference. I was the same location as my Fluke.

captainshooch

@mosca mine are connected before the SSR. It tells me voltage available to the circuit, the amps tell me the amount of power delivered by the SSR. Try connecting before the SSR, you can use terminal # 1 at the SSR. This should give you a constant voltage available which you can the multiply by the amps and get an accurate amount of power in watts being used. Like in this pic my voltages are always bet 243 and 247. On this particular day I had 247 volts and the SSR was letting 16 amps through to the element for a total of 3952 watts of power being used.

Lloyd

Why do I suddenly feel controller envy?

olddog

How about this big mother I am building for a member. I have got as far as I can go until more parts arrive.

captainshooch

@olddog you sure build some awesome stuff =D>

captainshooch

@Lloyd prolly cause I am burning up w/jealousy over that fance boiler u just got :((

captainshooch

my UJSM under a blankie :D I had to put on some socks and a jacket. 47F here this am...still wearing shorts, how about u @Smaug

CothermanDistilling

winter in FL sucks, huh @captainshooch ??? LOL...

captainshooch

@CothermanDistilling yup, it sucks to have to wear socks with a jacket :D

Smaug

Had to put on my extra thick tank top for half the day. Back into the 80s now.

captainshooch

u live in paradise...that's why so many are retiring and moving down there. Good, cause it keeps em outta here :D

crozdog

@captainshooch said: mosca mine are connected before the SSR. It tells me voltage available to the circuit, the amps tell me the amount of power delivered by the SSR. Try connecting before the SSR, you can use terminal # 1 at the SSR. This should give you a constant voltage available which you can the multiply by the amps and get an accurate amount of power in watts being used. Like in this pic my voltages are always bet 243 and 247. On this particular day I had 247 volts and the SSR was letting 16 amps through to the element for a total of 3952 watts of power being used.

Your theory sounds good, but is flawed in practice sorry. You cannot measure different things in different parts of a circuit & associate them like you have. To measure the power you need to measure the current & voltage at the SAME point i.e. the output of the SSR.

@olddog - not sure you're right. A PWM cct simply turns on the SSR for the period that the duty cycle is on ie the time % the output is on vs off. This will result in a "chopped" AC waveform on the output of the SSR. If the duty cycle is smaller than the applied AC frequency eg 1/500th of a second vs 50hz, the output sine wave may appear to be pulsed as you say, however if the duty cycle is large say 1 second, many full sine waves will pass before the output of the SSR is turned off.

I understand that the SD DIY kit is a phase angle controller. It works by altering the % of the AC waveform that is passed to the output. It's output will also be a chopped waveform, however the chopping will always be at the same point (due to the phase angle) whereas a PWM controller will be slightly different each time the unit is used as it depends where in the cycle the waveform is when the unit is turned on.

The difference can be seen on this page. The 4th graph is the Phase angle output while the PWM graph on the right is for a pwm cct with a duty cycle smaller than the AC frequency.

@moscca, your Fluke is probably measuring true RMS (what you want) while the panel meter isn't. Non RMS volt meters will display incorrect results with both PWM & phase angle controllers. One thing the panel meter will give you is a way to repeat your settings time and time again, however for my way of thinking setting a pot to position 5 on the dial is close enough :-) especially considering all the other variables eg wash %ABV, atmospheric pressure, air temp, coolant temp etc.

Please don't think I'm having a go at anyone or that I know it all, just there is a lot of misunderstanding of how these circuits actually work.

captainshooch

@crozdog no offense taken. Why would you wire the volt meter after the ssr and get funky readings when u can wire it pre-ssr and at least get accurate volt readings? My still shed is on a separate meter and my wattage consumption is up tp par with the electric company charges

CothermanDistilling

For power consumed by the element, you want voltage across the element multiplied by current through the element, the SSR may have a voltage drop of a volt or two, which would make your reading inaccurate. P=I*E does not really work straight away on semiconductors such as in an SSR... for example, a simple silicon diode has a voltage drop of .7V, whether you put 1A or 100A through it...

lets use DC for an example to make it clear: 100Volts with no diode across a 10 Ohm heating element would be 10A. 100 volts at 10A is 1000W. But with 2 diodes in it, we only have 98.6V across 10 Ohms, and 9860 watts

but if you measured across the source and not directly across the elements, you would see the full 100V.

Clear as mud? throw in AC and RMS and stuff and you will pull your hair out ;-)

CothermanDistilling

Here is the datasheet (PDF) for the one newark carries, only 25A, I actually paid $45 for one... SD is a true bargain, as usual..

CothermanDistilling

An omega info sheet (PDF): Center right hand side of page Z-126

In the ON state (figure 7b), the TRIAC exhibits a nearly constant voltage drop (i.e., almost independent of load current) approximately equal to that of two silicon diodes - less than 2 volts.

Read over a snifter of apple pie for best results!

captainshooch

@CothermanDistilling so you think it is safe to say that I am within a couple of volts? Close enogh for me.

captainshooch

@FlyboyTR posted a while back the following actual voltages to the element

@FlyboyTR said: I have tested the unit and it works good. No electrical leakage to boiler (safe to operate). Everything functions as it should. The voltage stays near zero until the POT is above 20% and then flattens out around 90%. Presently I do not have any vent holes. Temps do not appear to be a factor until it is operating at approximately 80-85%. Since I have a bypass switch set-up, all initial heat-ups requiring 100 output will be done in bypass mode (zero heat output) then switched back to the controller once boiler temps are near operating range; then switch bypass off and adjust the controller accordingly. At this point I don't ever see a need for any type of cooling or even holes. However, extended run times may prove differently.

It appears I have been hogging this thread today...my apologies for the multiple posts.

Attached is a small spreadsheet showing the dial (POT) setting, voltage and percent of capacity. These numbers were taken while the unit was operational (system was under load). Max voltage (no load) is 240vac. Max voltage (under load- 5,500 watt element) is 236vac. All numbers on the spreadsheet are based on the a working max of 236vac.

Using his data it then turns out that at 16 amps aprox. 70% setting on the pot. the actual voltage to the element is around 160 and 2560 watts. @crozdog, do you agree?