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BrewerOneEleven
03-12-2017, 06:31 PM
Need some help! I am building a 1.5-2bbl pilot system and have 208v single phase outlets which are shared with a distillers still. I will run 2-3 elements in the boil kettle. The distiller just turns on and off the breakers for each outlet to control the heat to his still. I want the ability to simply control each element so I can dial them down to 50-75% power. What would be the simplest (cheapest) way?

SMiller
03-12-2017, 07:57 PM
A couple years ago I used electric elements just wired directly to safety switches. For what you'd like I recommend talking to Kevin at Brewmation. They can build a simple panel for that. Check out brewmation.com

troybinso
03-12-2017, 09:08 PM
There is a shop called high gravity brewing that mostly focuses on homebrew stuff, but they make electric element controllers that work great. I have one that works on percentage output for the boil kettle and another that has a thermostat to control the hlt. This is for a 1.5 bbl brewhouse.

arcangel
03-21-2017, 08:31 AM
I use a solid state relay (SSR) connected to a temperature controller. The temperature controller outputs 5 volts DC at a few milliamps to the SSR and it switches the current to the element. The SSR I use is the size of a match box and will switch 9 kW.

My suggestion would be to purchase 3 SSRs, one for each of the elements, and a timer that say, in a minute, would give you 30 seconds 'on' and 30 seconds 'off'. You could chose whatever ratio suited you and reduce the 'on/off' period to seconds to give better control.

Best regards,
Michael George
Alias Arcangel.

Swags
05-12-2017, 01:17 AM
Sorry to hijack but I'd like to know which SSR and temp. Controller you are using. I need to control a 10kw element on my HLT. Thanks




I use a solid state relay (SSR) connected to a temperature controller. The temperature controller outputs 5 volts DC at a few milliamps to the SSR and it switches the current to the element. The SSR I use is the size of a match box and will switch 9 kW.

My suggestion would be to purchase 3 SSRs, one for each of the elements, and a timer that say, in a minute, would give you 30 seconds 'on' and 30 seconds 'off'. You could chose whatever ratio suited you and reduce the 'on/off' period to seconds to give better control.

Best regards,
Michael George
Alias Arcangel.

rdcpro
05-15-2017, 05:29 PM
Sorry to hijack but I'd like to know which SSR and temp. Controller you are using. I need to control a 10kw element on my HLT. Thanks

SSRs come, of course, in a variety of sizes, but it sounds like his SSR is designed to switch 40 amps, which is not enough to power a 10KW element at 240 volts. Maybe it would work at 208 volts, but you're right at the limit. An SSR operated near it's limit will run quite hot, so if you need, say 42 amps (10KW / 240V) then you might want one rated for a higher current, say 50 to 60 amps.

There are a lot of things to consider when choosing an SSR, but here's a good primer on them: http://www.phidgets.com/docs/Solid_State_Relay_Primer Pay close attention to the parts where the article explains how they can fail--you want to account for that in your design. For example, SSRs typically fail "closed" meaning they don't turn off when they fail--they short out. So now your HLT will overheat. To account for this, you have a high alarm that shuts down the main power if the high limit is reached.

SSRs also conduct some electricity even when they're off, so some designs will put a relay in series with it, that will drop out when the unit is not actively controlling. So when the heater "on/off" switch is off, the relay isolates the load from the SSR. But you should still lock out and tag out the system when working on or cleaning the elements.

As for the controller, how closely do you need to control the temperature of the HLT?

If you don't care too much about the exact temperature, you can simply turn it off and on with a thermostatic (on/off) controller and a regular mechanical relay rated for the voltage and current. There will be some deadband; For example, if you want the HLT to be above 175F but below 180F, you could put that setpoint to turn on at 176 and off at 178, for a 2 degree deadband. But if you're trying to heat strike water to a very specific temperature, though, you would use a PID controller, and tune it so that it ramps up quickly, but doesn't overshoot, and stops exactly on your setpoint. Most PID controllers have an "auto tune" function that should work fine for an HLT. Make sure your controller has an electronically switched output; IOW, it's designed to drive an SSR. This type of control turns the SSR on and off rapidly, varying the power output with the ratio of the "on" and "off" time. When it's "on most of the time" it supplies a lot of power, and when it's "off most of the time" it supplies little power.

For example, let's say the control period is 2 seconds. This means the controller will switch the SSR on and off, repeating the cycle every 2 seconds. When your HLT is cold, the SSR is probably on 100% of the time. So for each 2 seconds, the SSR is on for 2 seconds. Later, as it approaches setpoint, you don't want it to overshoot, so the controller turns down the power, and the SSR might be on for only .5 seconds, and off for 1.5 seconds. It will continuously adjust this ratio, repeating every 2 seconds.

If you have a microwave oven with adjustable power levels, it probably works the same way, though with a much longer duty cycle or period. Set it for 50% power, and the oven is "on" for 15 seconds and "off" for 15 seconds. This equates to a period or duty cycle of 30 seconds.

One last thing: People often say "I need a PID controller" when in fact, they really don't need that type of control. If you're ok with your HLT being within 2 degrees of setpoint, you don't need PID control. A thermostat works fine, because with the thermal mass of the HLT, it takes time to change temp by that much, so it won't cycle too quickly. If you need a very precise temperature, or the thermal mass is low then the t-stat will cycle too quickly, so use PID.

Regards,
Mike Sharp

arcangel
05-20-2017, 05:44 AM
Hi Swags,

I am sure the response from Mike Sharp has probably answered all your questions.

Just to give you a bit of background as to why I chose a PID controller and a SSR.

1. The object is control the temperature of a 12 gallon fermenter with a 260 watt pad heater which is rather too much powerwise, but the dimensions fitted the FV. A bimetallic thermostat would not have given the control required. I use a T type thermocouple as a sensor.
2, I have in mind to grow Aspergillus oryzae as a precursor to making Sake. This require a temperature around 100 degrees F.
3. I could have bought a PID with an inboard relay capable of switching 1250 watts, but considered that if it failed I would have to buy a new PID controller, considerably more expensive than a new SSR.
4. My TIG welder can pulse between 5 and 220 amps at 500 Hz. The electronics use solid state IGBTs. Relays could never do this (for long).

By the way, if the instructions that come with the PID baffle you (mine were in Chino-English), there are some good instructional videos on youtube.

Good luck with your project.

Best regards,
Michael George