Volt amp meters

[elbono]

With utilities having a -5% to +5% variance for residential service anyone without active power correction who is watching an Amp value could be making two very different runs on different days. I have always wanted something like the Auber controller with the power profile mapped to Wattage and a watt meter display.

The current will change when the voltage changes so watching either one is as good as watching the other.

It's not a matter of day to day but minute to minute. I see a 5v drop when my heat pump kicks on. Less when the neighbor's unit kicks on.

The utility tolerance is probably at the transformer, definitely no further than the top of the service panel. There is voltage drop in your wiring as well.

Surprisingly I don't notice a difference in output rate on the pot still, a packed column running near flooding is a different story.

[kennstminet]

How low can you turn the power down to before the meter starts having problems?

Thanks for asking this question which made me look outside my box.
With 220V and 2200W my heater has 22 Ohms. The Wattmeter starts flickering if the power regulator is set below 160 Watts. This corresponds to 60 V RMS Voltage.
This is not a real problem for me.
However in a 110 V environment, the situation changes. I have not tried it, however my calculator says:
A 2200W heater would have 5,5 Ohms. 60 V RMS would correspond to a lowest power of approx. 650 Watts.
I think this would be very inconvenient.

Then I rewired the Wattmeter to receive the voltage from the input side of the SCR power controller (full 220V).
The meter then displays the mains voltage (220 V in my case) rather than the reduced voltage, however the controlled Power and the Amps are still correctly indicated.
The Watt indication works correctly down to nearly zero.
I have not tested if the Watts indication reacts properly to fluctuations of the 220V mains voltage. However, I do not expect a problem.
Therefore, I will leave the wiring in that configuration and recommend it as well for 110 V applications.

[NormandieStill]

You really dont need to know the volts going into the element. Or rather... it's no more useful than knowing the amps consumed by the system. If you put a volt / ammeter on the input line then you know the line voltage of your circuit and the current consumption of your still. Multiply these together and you'll get the volt-amps (near as dammit the watts into the still).

No danger of frying your meter and you get to practise your mental arithmetic. And if you really can't then you can make up a table of common values or just keep a calculator to hand.

If I push my still to the max (4.5kW nominally) then I consistently get a voltage drop of around 10v. That's the effect of the wiring diameter on my circuits in the shed. Not sure that my budget will extend to replacing the 40m of 2.5mm with 4mm any time soon though.

[Windy City]

I used this meter in my most recent build of my pumped reflux side column still.
I have three elements in my boiler. I mostly just have it set to amps, one line of the gauge for each element.
But you can read volts, amps watts etc
https://www.automation24.com/digital-mu ... KYQAvD_BwE

This is the data sheet.
https://media.automation24.com/datashee ... MFM384.pdf

This is the manual.
https://media.automation24.com/manual/us/400298.pdf

You have to buy the current transformers separately.

[Yummyrum]

I used this meter in my most recent build of my pumped reflux side column still.
I have three elements in my boiler. I mostly just have it set to amps, one line of the gauge for each element.
But you can read volts, amps watts etc
https://www.automation24.com/digital-mu ... KYQAvD_BwE

This is the data sheet.
https://media.automation24.com/datashee ... MFM384.pdf

This is the manual.
https://media.automation24.com/manual/us/400298.pdf

You have to buy the current transformers separately.

Not the cheapest Puppy at the pound , but it sure does look like it would behave well .
Seems to have the seperate supply as well as T-RMS .

[Yummyrum]

If you put a volt / ammeter on the input line then you know the line voltage of your circuit and the current consumption of your still. Multiply these together and you'll get the volt-amps (near as dammit the watts into the still).

Not quite so Normandie,
Whist the current flow on the input is the same as the output , the voltage at the input will always be constant ( at the supply voltage) where as the voltage at the output will vary as the controller is adjusted.
Multiplying the input voltage by the current will give a wrong answer .

However , if you know the resistance of your element , you can multiply it by the current squared to get the power.

P=RxIxI

But again it comes down to having an accurate current reading taken via a T-RMS meter.

[elbono]

Multiplying the input voltage by the current will give a wrong answer .

Actually it depends on the internals of the meter. Most of these "power monitors" sample the AC waveforms several times in a power cycle.

I believe a HT7017 chip is used frequently. It can be configured to sample between 16 and 260 times per 60hz cycle. Using these instantaneous values when the current is zero it doesn't matter what the voltage is. Zero times less than infinity is zero.

I had one hooked up like Normandie describes and noticed the kw reading was correct (NOT volt reading x amp reading) and infered this is what was happening.

Edwin noticed this too back in 2015
viewtopic.php?t=55602

[Yummyrum]

Multiplying the input voltage by the current will give a wrong answer .

Actually it depends on the internals of the meter. Most of these "power monitors" sample the AC waveforms several times in a power cycle.

I believe a HT7017 chip is used frequently. It can be configured to sample between 16 and 260 times per 60hz cycle. Using these instantaneous values when the current is zero it doesn't matter what the voltage is. Zero times less than infinity is zero.

I had one hooked up like Normandie describes and noticed the kw reading was correct (NOT volt reading x amp reading) and infered this is what was happening.

Edwin noticed this too back in 2015
viewtopic.php?t=55602

Agree 100% elbono . The Chips can sample and do the math many times a cycle .
I mentioned this back on the Dual controller topic last week
viewtopic.php?p=7765198#p7765198

I was just saying that if a voltmeter reads X volts and the Ammeter reads Y amps ( as in you are looking at an LED display ), you can't just multiply them and get the correct power when the Voltage is measuring the input voltage .

[Salt Must Flow]

Not to change the subject, while absolutely changing the subject ... would you say that controllers that pulse from 0%-100% power be more accurate in comparison to other controllers that you guys are talking about with these readily available volt/amp/watt meters? Just generally speaking. I totally understand that even these pulsing controllers can't compensate for the irregularities in the power grid. Considering that ... would you say that those controllers (like Auber controllers) be generally more accurate & reliable in comparison? I've just always wondered. As an example, if you're using a 5500W element at 50% power that should be operating at 2750W.

[shadylane]

Damn good question.

Just guessing.
I think on/of duty cycle would be easier measure than a SSVR sawtooth wave form.

[elbono]

.would you say that controllers that pulse from 0%-100% power be more accurate in comparison to other controllers that you guys are talking about

No

[elbono]

.would you say that controllers that pulse from 0%-100% power be more accurate in comparison to other controllers that you guys are talking about

No

To answer the question I think you meant to ask: which is better?

There are advantages to both.

Accuracy? The phase control units (SSVR) in theory are infinitely accurate, the Auber units give you 100 discrete steps. In reality good luck adjusting a phase control unit to 96.43% vs 96.42%

Convenience? You don't need a meter for repeatability with the Auber units.

Warm and fuzziness? Since you don't need a meter the Auber units conceal all the nasty power line stuff my meter makes obvious.

I use a phase control unit presently but am laying plans to build my uber alles controller that will use zero crossing control (SSR). It will have a meter though.

[Salt Must Flow]

Damn good question.

Just guessing.
I think on/of duty cycle would be easier measure than a SSVR sawtooth wave form.

I only know the most basic stuff about electricity so I cannot debate what you guys have been analyzing.

I recently messaged Auber Instruments this question:

I'm curious to know how your volt/amp meter would work with a DSPR400 as shown on this page: https://www.auberins.com/index.php?main ... cts_id=955

I know the DSPR400 pulses on/off to regulate power to a heating element. Wouldn't that cause the volt/amp meter to flicker on/off with the power sent to the element?

Today they replied with this response:

Thanks for contacting us. The power meter will not flicker on/off during use. The voltage is wired to measure the input voltage, which is 240VAC in this case. It will remain stable. The amperage meter will show the current passes through the SSR. However, this is a very simple amp meter. As the controller reduces the power percentage, the reading on the amp meter will drop as well but it is not intended to be an accurate reading.

Best regards,

Well I don't really know how to interpret that reply technically speaking, but I only asked due to curiosity. I applaud their reply as being honest by saying, "it is not intended to be an accurate reading". I've always just used the DSPR400, set the % power and based on the % power I have always inferred the watts based on my 5500W element. For instance 50% of 5500W is 2750W. Any discrepancies with the power grid I just ignored because there's no reasonable way for me to be more accurate than that. Long story short ... no meter required. I just go by % power and infer the watts.

I originally started with a SSVR & potentiometer, tried a couple of those volt/amp/watt meters and they didn't appear to work quite right. That's when I decided to go with the Auber DSPR400.

[Yummyrum]

It is the one thing that I prefer about SSRV controllers over % controllers like the Auberins .

I know the supply voltage is all over the show here . We have solar and I can look at the graphs and watch the grid voltage variations . I saw that grid was at 245.6v so I turned on the aircon to get some free power ( we only get 4cents /kwh but have to pay around 28c )
Anyway , with one aircon on , the supply dropped to 241.2v

On a sunny day the grid is fairly constant , but when its cloudy , it can be vary significantly . And as we live in a niebourhood that has almost everyhouse on solar, it can sometimes swing from around 237-247v …. Incidentally at which point out solar inverter shuts down as the grid voltage is too high .

So today with a slightly high 245.6Volts , my 2400w 240v rated element would be running 4.7% more power than it should . It also means I am running my element at much higher power than it is rated at .

An ammeter would show it as 10.23 amps on 100% power where I would be expecting it should be 10Amps . ( blindly believing the grid was at 240v)

I think monitoring of the Mains voltage is probably a useful tool if using a Percentage controller . Just so you can take these into account .
But at the end of the day , does it really matter if the reading is a few % out ? . It has to be way better than the tens of % out that a non T-RMS meter would display .

[Salt Must Flow]

Yummyrum I follow what you're saying and that kinda confirms what I've always assumed. A few % off one way or another, but reasonably accurate is my interpretation. Sorry to briefly derail the thread, but I thought it might be relevant to inquire.

[Yummyrum]

Not at all a derailment Salt . I think it is actually quite relevant to the topic of being able to measure or determine the power used as accurately as possible .

If you said I turned my power down to 1500watts ( using your Auber % controller ) I would believe your estimation before I would believe someone with a $10 Ebay meter .

And even if the supply voltage is so far out to cause a 5% error at 100% power , at 50% power it is only 2.5% out and it is these lower power setting readings off a phase controller ( SSRV) that really are the most inaccurately displayed on cheap meters.

[shadylane]

Something that measures +or- 10% of the watts is good enough.
Amps and volts measurements are prone to mistakes.
When the two are multiplied, the mistakes get even worst.

[elbono]

I would believe your estimation before I would believe someone with a $10 Ebay meter .

I use a cheap Home Depot meter which agrees well with my very cheap Amazon meter.

In truth I can't observe a difference in output rate on my pot still when either meter says the voltage changed by the normal 2 or 3 volts during a few minutes.

[Yummyrum]

Heres another . It’s only a Current meter , but its True RMS . And only $13.95 USD
https://www.verical.com/pd/murata-manuf ... lsrc=aw.ds

[still_stirrin]

My controller has both a voltmeter and an ammeter. I rarely look at the volt meter, but I adjust “power input” based upon the ammeter. Incidentally, BOTH meters are the “bouncing needle” type of (analog) meter, meaning they’re quite reactive and give a more “RMS” indication. I don’t really care about the actual power input so much as a gage of where I normally run the boiler for the vapor production rate (strip or spirit run) desired.

It’s not needed to calculate power consumption, rather just help me adjust the boiler so I get repeatable performance. Adjusting the VM valve, even a little, during reflux operation makes a huge difference on performance (and %ABV at the spout). Water (source) pressures and temperatures will affect the reflux condenser significantly too and can change the product outcome as well. “Differential” measurements simply aren’t necessary when it’s the “integrated” product that you’re trying to control.

The exception, however, would be for “automation nerds” who are trying to take a nap while running their still. But someone has to change the collection jars anyway, right?

The secret here really is to gain EXPERIENCE on how YOUR system operates optimally and the variation of products you produce. It’s impossible to “remotely” manage your system’s performance from this end of the internet. You have to learn it on your end.
ss

[Tōtōchtin]

I saw this a while back on Ali and sent a message to the vendor but never heard back. The ad states it works well with invertors. It the screenshot it looks like a graph of a chopped off sine wave but with the screen on my phone I can't blow it up big enough for me to read it. For the price I think I will still order it if I don't hear back from manufacturer and will just put it on the input side of things. I too have a Auber 400 to control amps going to element.
Tōtō

https://es.aliexpress.com/item/1005002475255535.html

[elbono]

That's a great looking option. I wish you posted that a month or two ago before I bought another one. That seller has lot's of similar one's I can't decide which one I want.

Your link didn't work for me here's a link to their store:
https://m.aliexpress.com/store/11012495 ... extParams=

[ThomasBrewer]

If you use something like the Auber DSPR220 distillation controller, a panel meter is sort of superfluous. You tell it what percent of the boil element power you want to use, and it outputs an appropriate duty cycle. If you set it to 20% while connected to a 5500W element, you can be reasonably certain that the heating output is 1100W. Even if it's not exactly that, it should be the same output power (within a narrow tollerance) every time it's set to that 20% setting.

[still_stirrin]

If you use something like the Auber DSPR220 distillation controller, a panel meter is sort of superfluous. You tell it what percent of the boil element power you want to use, and it outputs an appropriate duty cycle. If you set it to 20% while connected to a 5500W element, you can be reasonably certain that the heating output is 1100W. Even if it's not exactly that, it should be the same output power (within a narrow tollerance) every time it's set to that 20% setting.

Exactly what I was saying. Absolute values don’t mean much. But relative values tell you where your consistency is.
ss

[shadylane]

Absolute values don’t mean much. But relative values tell you where your consistency is.
ss

Accuracy is needed is when folks start comparing the values.
An example would If two people were comparing packing in their 2" columns and need to have accurate wattage measurements to avoid being mislead.

[elbono]

If you use something like the Auber DSPR220 distillation controller, a panel meter is sort of superfluous. You tell it what percent of the boil element power you want to use, and it outputs an appropriate duty cycle. If you set it to 20% while connected to a 5500W element, you can be reasonably certain that the heating output is 1100W. Even if it's not exactly that, it should be the same output power (within a narrow tollerance) every time it's set to that 20% setting.

The problem is you have 20% of something that isn't within a narrow tolerance.

When my HVAC unit kicks on my power to the element drops 4%, if the neighbor's unit kicks on at the same time it's down 6%. Throw in seasonal variation and it will be worse.

Does 6% really matter? I don't see a change in output rate on my pot still. I haven't run the column since I went electric but I think I'll see effects there.

[kennstminet]

If the voltage drops by 6%, the resulting heating power drops by 11,6%.
A change in output rate of 11.6% does not really matter for most people. A run of nominal 3 hours would take 3hours and 21 minutes.
In real live, the voltage does not stay 6% lower all the time, the effect will be much smaller.

I'm an electronics engineer and when I measure something, I want to measure it exactly. It's in my genes, I can't change it.
Most people are not as crazy as I am.

[elbono]

If the voltage drops by 6%, the resulting heating power drops by 11,6%.
A change in output rate of 11.6% does not really matter for most people. A run of nominal 3 hours would take 3hours and 21 minutes.
In real live, the voltage does not stay 6% lower all the time, the effect will be much smaller.

I'm an electronics engineer and when I measure something, I want to measure it exactly. It's in my genes, I can't change it.
Most people are not as crazy as I am.

Same here if it's worth measuring it's worth measuring accurately. I already squared the voltage, my numbers were power fluctuation.

Fluctuations during a run and between runs are two separate things I want to reduce.

I can't see a difference in the stream off the spout or in time to fill a pint jar on the pot still so I'm not sure it's needed here turning the pot to the same mark may be close enough. But as you say, I'm crazy and I probably won't stop readjusting when I see the voltage change

[kennstminet]

I recently did some measurements of product rate out of the spout and electrical heating power supplied to the heater with my potstill.
I calculated the power the condensor had to knock down for condensation and compared to the supplied power. The difference is the heat loss of the whole still setup. I used this calculator: https://hobbybrennen.ch/Rechner/en/Dist ... yWatt.html
This was an interesting exercise. After determining the power loss, I had an aproximate value of the real power that was driving the vaporization.
There was a clear and direct proportional relationship between that real electrical power and product rate. A 10% power increase made the product rate faster by 10%.
However there was several minutes time lag between power change and product rate change. I measured the product rate by measuring the time required to fill a 50 ml jar with a stopwatch.

When I try to explain such experiments to my wife, she usually responds: "Do be quiet and take your pills"

[elbono]

I measure time to fill a jar in minutes so I wouldn't notice 10%, if I did I would blame it on the lack of resolution of my measurement unless it lasted for more than 1 jar.

Of course the output is slowing through the run so something else to consider.

While I'm a nerd about making accurate measurements I don't claim my 5% power input variation changes my product as much as my mashing skills do.