Digital volt/amp meter

[sambedded]

I finally received my meter from China. Cute little thing.

I've got mine today also. Have done some testing. If connected after controller (in parallel with a heating element) resistor at voltmeter power supply (see picture on 1-st page) became very hot. Exactly as I expected. It works OK only if you run controller on 100%. On 50% of power resistor start smoking after 20 sec.
But if you connect this device before controller and put a heater live wire through ammeter hole - it works OK. This way it works only as ammeter. Because its hows constant voltage (input voltage) and current through heater. Amp reading not very precise - at 1/4 of power (120 V RMS) it shows 4A instead of real 5A. However it much better than analog ammeter shows.

[mash rookie]

I finally received my meter from China. Cute little thing.

I've got mine today also. Have done some testing. If connected after controller (in parallel with a heating element) resistor at voltmeter power supply (see picture on 1-st page) became very hot. Exactly as I expected. It works OK only if you run controller on 100%. On 50% of power resistor start smoking after 20 sec.
But if you connect this device before controller and put a heater live wire through ammeter hole - it works OK. This way it works only as ammeter. Because its hows constant voltage (input voltage) and current through heater. Amp reading not very precise - at 1/4 of power (120 V RMS) it shows 4A instead of real 5A. However it much better than analog ammeter shows.

With all due respect I am not sure why you insist on using it wrong.. You need to use it as designed. It is intended to show you line voltage in and amperage draw. That will give you correct information to work with for calculations of vapor speed and reflux ratio. It is a simple meter. Why are you screwing with it and what are you trying to learn? What do you expect to learn? Do you understand power application relative to distilling? I see no value related to distilling from your post.
Please correct me if I have missed something.

[sambedded]

With all due respect I am not sure why you insist on using it wrong.. You need to use it as designed.

You exactly right - it needs to be used as designed. Unfortunately it's not designed for non-sinusoidal AC waveform. And AC waveform after phase-angle controller is not a sinus.
BTW - do you understand how phase-angle controller works?

Dimmer_60_volts.png (5.47 KiB) Viewed 2265 times

Blue curve represents voltage on controller input (sinusoidal form), red curve is an output at ~40% of power. As you can see it doesn't look sinusoidal.

It is intended to show you line voltage in and amperage draw.

It's not so straightforward for AC as you think. Do you know what voltage and amperage this devise shows - RMS, Peak or Average? If it's not RMS you can not use it for power calculation. Please read this - http://www.allaboutcircuits.com/vol_2/chpt_1/3.html" onclick="window.open(this.href);return false;" rel="nofollow and the chapter "Average electrical power" here - http://en.wikipedia.org/wiki/Root_mean_square" onclick="window.open(this.href);return false;" rel="nofollow

What do you expect to learn? Do you understand power application relative to distilling?

I'm trying to find a way how this meter can be used with phase-angle controller and how correct it's reading.
My conclusion:
- You can not use it to measure voltage on heating element since it's power supply limitation.
- You can use it for amperage measurement, but reading not very accurate.

I see no value related to distilling from your post.

I hope that other forum members will see a value .
What exactly you don't understand from my post?

[heyhaychapman]

Thanks Rad for explaining RC power.

Thanks Sambeded for your advice on digital meters on a phase angle controller. I'll take your recommendation and try an analogue voltmeter.

My reading of what you have written is that it probably doesn't matter what type of analogue meter you use but a volt meter is a good choice because it has a nice wide scale? You are probably only looking to get a better idea of what effect adjusting the potentiometer has and maybe for a reference point to help find the same spot next time?

[mash rookie]

sambeded, I am not trying to bust your chops. If you are saying they dont work I suppose I am not surprised for $12. Yes, I understand how phase angle control works. No I don't know how they are measuring voltage or if they are accurate. I haven't even looked at it yet. When I get it put together I will check it with my analog and digital meters.

Please explain what I might understand by knowing voltage on the element? How I can use this information? I guess this is my misunderstanding about your post. I am missing something.

- You can not use it to measure voltage on heating element since it's power supply limitation.
- You can use it for amperage measurement, but reading not very accurate.

- - That sucks, but again it was $12

My reason for wanting the information this meter advertises is for calculation of vapor speeds as I continue to study different packings and reflux ratios. If it is inaccurate it still may have value if it is consistent. It will be easier to record than analog.

My tests are done in a glass column so that visual observations of performance are noted with vapor speeds and ABV results. It has produced great results. Typically only recording amperage I was surprised to find high line voltage when I bothered to check it. I had to go back and correct my notes. Was the line voltage high those days as well?

I am hopeful that it functions well enough to provide me consistent information.

[sambedded]

If you are saying they dont work I suppose I am not surprised for $12.

It works OK, but only if no phase-angle controller involved.

Please explain what I might understand by knowing voltage on the element? How I can use this information? I guess this is my misunderstanding about your post. I am missing something.

My reason for wanting the information this meter advertises is for calculation of vapor speeds as I continue to study different packings and reflux ratios. If it is inaccurate it still may have value if it is consistent. It will be easier to record than analog.

To calculate a vapor speed you need know power dissipating on your heater. To calculate a power you nedd to know RMS Voltage and/or RMS amperage.
If you are using phase-angle controller than analog and cheap digital Volt/Amp meters give you wrong reading. And you'll get completely wrong power value based on that readings.

Please read this article - http://www.allaboutcircuits.com/vol_2/chpt_1/3.html" onclick="window.open(this.href);return false;" rel="nofollow

It describes AC voltage measurement, Power calculation, meaning of RMS etc much better than I can.

[heyhaychapman]

Interesting link Sambedded. Certainly shows how phase angle modified voltage is tricky to calculate accurately. What about Mash Rookies point ... so what if the result is untrue as long as it is repeatable? Or are you saying the results will vary every time even with consistent wash ABV volume etc

[sambedded]

.. so what if the result is untrue as long as it is repeatable? Or are you saying the results will vary every time even with consistent wash ABV volume etc

results are reproducible but only if you are using same type of meter and same heating element. As soon as you change meter or heater- your new results will not be consistent with previous.

[heyhaychapman]

Hey I found this over on Pintoshine's site. To misquote Crocodile Dundee ..." No mate THIS is a controller"
http://m.youtube.com/#/watch?v=7l5Y8kI- ... l5Y8kI-8Zw" onclick="window.open(this.href);return false;" rel="nofollow
Meanwhile back to low budget life, the search for a cheap controller goes on ...

[sambedded]

I finally received my meter from China. Cute little thing. I have a 5500 kit that I gave the amp meter to BM. I need a plug for it then I will get it built soon.

Have you tried it yet? How does it work with your setup?

[mash rookie]

I used it last weekend. I have it wired up on a continuous rig I am testing. I thought it did pretty good. The volt meter only has value before you apply a load.
The amp meter was easier to read than my conventional meter but who knows how accurate it was. It was interesting to see that my line voltage is a little higher than I thought (maybe not though) and that it was different but consistent on different days. I think I will switch it out with my boiler controller for documenting new packing tests. That could create a problem with comparing old notes though.
MR

[feijoa]

Same experience here - interesting, but not sure of the accuracy.
Better than no meter though.
And the price and availability is good (eBay)

[sambedded]

It was interesting to see that my line voltage is a little higher than I thought (maybe not though) and that it was different but consistent on different days.

Could you share the numbers?

[Aussiedownunder01]

Same experience here - interesting, but not sure of the accuracy.
Better than no meter though.
And the price and availability is good (eBay)

You are wasting your money with phrase controllers they dont work
i got one it was reading high connected test meters reading where they should mine got up to 265 volts
Go for a good analogue meter that reads volts thats all you need
If i can find it i will post a link
Here http://www.ebay.com.au/itm/300V-AC-ANAL ... 19d5e94451" onclick="window.open(this.href);return false;" rel="nofollow

[mash rookie]

The first day It showed my line voltage at 240. Second day it was 236. Both without load. Next time I run it I will check it against my pocket meter. It has shown my single phase as high as 124 volts. I think they will work okay. I record voltage before load, then amperage. Any load will cause a low volt reading on that circuit. That does not mean that supplied voltage has changed. During a run I can turn it down for a second if I want to verify line voltage.

[sambedded]

The first day It showed my line voltage at 240. Second day it was 236.

It should be 240. Why you consider it high?

Any load will cause a low volt reading on that circuit.

Could explain it in details? I don' quite understand.
What is your connection schematic?

Thanks.