Why no dual voltage controllers?

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Whisky River

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I am thinking about making the switch from my all-in-one system to a single vessel electric system and I keep wondering why there don’t seem to be any dual voltage 120v/240v controllers available? I saw a post by @doug293cz (below) that made it seem like it wouldn’t be that hard to add a voltage selector to a home built controller but I have never seen one on a commercially available unit. For the cost of these controllers $500+ it would be nice to only have to buy one and have the option to use the full 240v or switch to 120v to reduce the watt density on the element.

https://www.homebrewtalk.com/thread...ement-need-some-options.727345/#post-10265098

Does anyone know of a dual voltage controller that I missed or if it really is that easy to add the capability to an existing controller?
 
Every controller I've bought from Auber works on 85 to 260 volts. That said, I've built out from the raw PID, not bought a turnkey type of thing.

Of course, there may be additional considerations in wiring to operate elements, pumps, etc, between mains voltages but the controller (e.g. brain box) itself probably isn't the issue.

And, yes, running a 240V element on 120V reduces the watt density a lot, since the element power drops by 75% (e.g. 4000W 240V element becomes 1000W element on 120V).
 
I am thinking about making the switch from my all-in-one system to a single vessel electric system and I keep wondering why there don’t seem to be any dual voltage 120v/240v controllers available? I saw a post by @doug293cz (below) that made it seem like it wouldn’t be that hard to add a voltage selector to a home built controller but I have never seen one on a commercially available unit. For the cost of these controllers $500+ it would be nice to only have to buy one and have the option to use the full 240v or switch to 120v to reduce the watt density on the element.

https://www.homebrewtalk.com/thread...ement-need-some-options.727345/#post-10265098

Does anyone know of a dual voltage controller that I missed or if it really is that easy to add the capability to an existing controller?
Designing a controller that will work with both 240V and 120V is quite simple, you just have to plan it that way from the start. How hard it would be to modify an existing single voltage controller depends on just how it is wired internally. In the simplest case of a "correctly" wired controller, it is just a matter of making a pigtail plug adapter. In other cases, you might have to rewire some of the internal connections, and in the worst case it might not be possible at all without a complete redesign.

Here's an example of a controller design that can be plugged into either 120V or 240V, which also shows how to wire the pigtail plug adapter:

DSPR120 1-Pump 1-Aux Dual Voltage Input contactor.PNG


Here's a version that allows you to plug into either 120V or 240V, and when operating from 240V to switch the element voltage between 240V and 120V:

DSPR3x0 DV-100 1-Pump 1-Aux Dual Voltage Input Output.PNG


Brew on :mug:
 
The Auber cube controller will run on 240 or 120v. You just have to make a special input cable that replaces the L2 with a neutral and everything works as expected. Of course, there is the topic of whether you're looking to run the whole thing on 120v occasionally or if you wanted to switch between voltages while plugged in to 240v. Further down the rabbit hole, are you trying to run a 240v element on 120v occasionally? If so, it will only put out 25% of the power.
 
or switch to 120v to reduce the watt density on the element.
I missed this line when I posted the previous reply.

Some commercial controllers have a maximum output parameter that effectively does the same... The blichmann brew commander for example, is capable of limiting the output to 10% or whatever you type in, even though it's shooting for a target temp. It just limits the cycle time the element can be on.

The Auber EZboil controllers DSPR-320 for example has mOUT:
1718385772562.png

It's a little less sexy because this parameter has to be adjusted in the menu system and is not conveniently displayed on the home screen like the BC.

Adding a switch to move the element output L2 hot to a neutral to make it output 120v is pretty easy. You'd need either a 30 amp capable toggle or use a relay/contactor to do it. On a commercial controller, keeping costs down is the name of the game and it would be silly to build in a feature that 90% of people wouldn't really use.
 
Thanks for sharing those wiring diagrams! I guess I might wind up trying to build my own controller if I can’t reconcile the price and limitations of the commercial units.

Bobby I think you really hit the nail on the head with your question. I was originally intending to use 240v input power and just reduce the voltage during the mash to reduce scorching, but I just can’t get over the idea that I would have to pay another $500 for a second 120v controller if I wanted to brew in any other location. I had intended to get a 9000w element and use it at 2250w when necessary to get the watt density as low as possible.
 
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Some commercial controllers have a maximum output parameter that effectively does the same... The blichmann brew commander for example, is capable of limiting the output to 10% or whatever you type in, even though it's shooting for a target temp. It just limits the cycle time the element can be on.
So then a question about the power output modulation. If reducing the power output using the controller just reduces the number of times per cycle that the element is fired (presumably at full power) then is there still a chance of scorching during these short bursts of full power, if solids have settled on the element?
Said another way, is there any practical difference between running a 9000w element at 50% modulated power compared to running a 4500w element of the same size at full power. Trying to understand the value of finding an ULWD element vs just using a higher watt density element throttled down to lower power.
Thanks
 
So then a question about the power output modulation. If reducing the power output using the controller just reduces the number of times per cycle that the element is fired (presumably at full power) then is there still a chance of scorching during these short bursts of full power, if solids have settled on the element?
Said another way, is there any practical difference between running a 9000w element at 50% modulated power compared to running a 4500w element of the same size at full power. Trying to understand the value of finding an ULWD element vs just using a higher watt density element throttled down to lower power.
Thanks
An important consideration when addressing this question is the mode of power modulation used. Most low cost controllers use a pulse width modulation mode. In this mode you have a fixed cycle time, which can usually be adjusted while not in operation, but when controlling stays constant. Then the controller turns on full power for a percentage of the cycle time that matches the percent power setting. For example, if the cycle time is 2 seconds (a common minimum cycle time for PIDs), and the power setting is 50%, then the controller will turn on full power for 1 second, and then be off for another second. For 25% power, you will get full power for 0.5 seconds, and then off for 1.5 seconds. Whether or not full power for 1 second is going to be a problem or not depends on how fast the element surface heats up when power is applied. If the element surface can reach max temp in 0.1 seconds, then you might have a scorching issue, but if it takes 2 seconds for the element surface to reach maximum temperature, then it wouldn't reach max temp if only on for a second or less, and you have much less chance of scorching.

The max surface temp an element can reach is going to depend on the watt density of the element, the fluid flow over the element (and whether it is laminar or turbulent), and whether or not there is any surface "contamination" on the element which would slow heat transfer from the element to the fluid.

All else being equal, the max surface temp of a 9000W element PW modulated to 50% is going to be higher than the max surface temp of a 4500W element running at full power, unless the heat up time of the element is longer than the cycle time of the PWM.

The Auber EZBoil DSPR controllers use something different than PWM. They turn on and off for individual cycles of the AC current/voltage waveform. So, that when calling for 50% power, they will be on for one AC cycle, and then off for the next. Thus when calling for 50% power or less, the maximum on time for the element will be 16.7 millisecond (0.0167 sec.) This short max on time will keep the element surface temp from reaching what it would with PWM. So, you are less likely to have scorching issues with this type of power modulation than with simple PWM.

EZBoil Switching Waveform.png


Learn more about power modulation modes in the Appendix (starts on page 12) of the attached .pdf.

In any case, you don't want to use an element with more power available than you ever actually intend to use, as you will have better granularity of power control if you choose an element that you can run from 0 to 100%, rather than 0 to 50%.

The above discussion just scratches the surface of this complex topic.

Brew on :mug:
 

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Not a lot to add, but a question; What size is this system? A 9000W element seems kinda overkill..I'm personally a bit paranoid about surface area wattage density and packing that much potential heat output just sounds risky. For years now 5500W ULWD has been a sort of defacto standard among homebrewers and has a great track record...The Auber DSPR based controllers are just icing on the cake and though they cost a bit more, are money well spent as the difference in price is pretty close to the cost of one ruined batch. Just my opinion; Leave the massive-wattage elements to the distillers and consider building aound the @Bobby_M vetted stock; https://www.brewhardware.com/category_s/1902.htm
 
You are correct that it should not be that hard. The anvil foundry switches between 120 and 240 with a switch and plug adapter. But, if you plug it into the voltage opposite of the switch, no more foundry.
 
You are correct that it should not be that hard. The anvil foundry switches between 120 and 240 with a switch and plug adapter. But, if you plug it into the voltage opposite of the switch, no more foundry.
I wonder why that is? In my designs, this cannot happen.

Brew on :mug:
 
Don't know, I have read others say it happened and it if in the manual.
Perhaps it's that the excess voltage fries the heating element, and since the element is bonded to the bottom of the kettle (and not replaceable) that bricks the unit. With my designs this might happen if you had the controller hooked to a 120V rated element and plugged it into 240V (pushing 4X the rated power thru the element), but with a replaceable element, the damage is much less expensive.

Brew on :mug:
 
So then a question about the power output modulation. If reducing the power output using the controller just reduces the number of times per cycle that the element is fired (presumably at full power) then is there still a chance of scorching during these short bursts of full power, if solids have settled on the element?
Said another way, is there any practical difference between running a 9000w element at 50% modulated power compared to running a 4500w element of the same size at full power. Trying to understand the value of finding an ULWD element vs just using a higher watt density element throttled down to lower power.
Thanks

Doug already hit the main explanation here, it's all about duty cycle. Many PIDs and the Brew Commander have a selectable cycle time, usually bottoming out at 1 or 2 seconds. That means at a setting of 50%, the element would be full power for either 1/2 or 1 second. Since the element is immersed in liquid, that's nowhere near long enough to scorch.

I'm definitely not diminishing the advantage of physically lowering the watt density maximum of any given element and if you're building a controller, it's probably only 10% more parts cost. The function could be added to any controller, even a commercial one, with a 30amp capable single pole, double throw switch. The wire on the element (that is not switched via the solid state relay) would just need to be switched between a hot source and the incoming neutral. The common of the switch goes to the element and the two throw contacts go to hot and neutral respectively. When I built my first controller like 12 years ago, I just used a double pole, double throw switch with a center off position as my element off, element 120v, or element 240v control with no contactor. The switches are not that common, but they're out there. These days it's actually cheaper to do it with a pair of 2 pole contactors and a low current 3 position selector switch.

Of course you have to make sure the neutral wiring is 30 amp capable.


The foundry does it a little differently. It's not just reconfiguring a single element. If it were, the 120v wattage would be 25% of the 240v wattage. I believe the 240v setting is putting another auxiliary element in series to increase the resistance. 1500 watts on 120v and 2800w on the 240v setting. Hitting the unit with 240v while in the 120v switch position would make 6000 watts and pull 25 amps (which is way more than any part of the wiring was meant for).
 
Of course you have to make sure the neutral wiring is 30 amp capable.
When you switch to 120V mode, the current thru the element, and thus also the neutral will be 1/2 of the current when running in 240V mode. For a 5500W @ 240V, the current at 240V is 5500 / 240 = 22.9A, and the current at 120V would be 11.45A. A 6500W @ 240V element will draw 6500 / 240 = 27A, so at 120V would draw 13.5A. So a neutral wire rated at 20A is more than sufficient for a circuit that will draw 30A or less at 240V.

Brew on :mug:
 
When you switch to 120V mode, the current thru the element, and thus also the neutral will be 1/2 of the current when running in 240V mode. For a 5500W @ 240V, the current at 240V is 5500 / 240 = 22.9A, and the current at 120V would be 11.45A. A 6500W @ 240V element will draw 6500 / 240 = 27A, so at 120V would draw 13.5A. So a neutral wire rated at 20A is more than sufficient for a circuit that will draw 30A or less at 240V.

Brew on :mug:
Of course it does. :oops:
 
Thanks all, there’s so much great information here, it’s really helpful to get a better understanding of how these systems work before diving in. I had always hoped to use a DSP120 or DSP320 based controller and seeing how detailed these wiring diagrams are makes me think it might be worth taking a shot at making my own controller.

@doug293cz or anyone, if I used the second diagram above for the selectable input and selectable output controller, would it be acceptable to substitute an Auber KCD4-WR for the Leviton 3032? The Leviton looks a lot more robust but for compactness of the layout, I wonder if the Auber could be substituted? Also can the unlabeled 120 to 240 control switch in the middle of the diagram just be any low voltage SPST switch? One last question, if one were to substitute a DVA-120 dual volt/amp meter for the DV-100, would you run the amp meter off the same red L1 line to the SSR?

Thanks again for all the great input.
 
It sounds like what you want is just a slight bit different than both of the diagrams. I didn't think you had any intention of powering the whole box on a 120v source but just that you want to be able to run the element output on 240v normally and pull it down to 25% maximum power via voltage selector switch.

The toggle switch version would look like this, though there are a few ways to do it. The switch has to be at least a double pole, double throw. The Auber switch is only a double pole single throw. The benefit of the Bryant 3025 is that it has a center off position so you don't need any other switches or relays to kill both lets of the element output. It shows an SYL-2352 but that's just because it's an older diagram from before the DSPR brains came out. I highly recommend one of the DSPRs.


1718750610670.png
 
Here's how I'd do it with contactors or two pole mechanical relays.

the blue push button is the pump on.
The orange push button is element enable/disable.
The black selector switch is 240v or 120v element output (in the picture turned to the left is 240v).
The volt/amp meter is wired in the correct spot as to display the actual voltage the element would get.


1718766459217.png
 

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Along similar lines to @Bobby_M diagram, here's a simple example using these 120v coil, 240v/30a NO/NC relays (such as https://www.amazon.com/Tnisesm-Mounting-Connect-Terminals-NT90-AC120V-10X/dp/B087G6D24G -- the COMMON of the relay will be on the output side heading to the heating element for the relay switching between Neutral and L1), a SSR and a DPDT center off switch (https://www.amazon.com/Baomain-Toggle-Switch-250V-Position/dp/B01JFGZEE6). You can fill in the rest of the power connection information based on what has already been posted.

Scheme-it-export-120v-240v-Switched-Element-2024-06-22-13-52.png
https://www.digikey.com/en/schemeit...ched-element-cda39453aacf4f36b28e1f356abefebf
 
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