StillDragon DIY Controller Kit

[mendozer]

How does one wire an ammeter and a 3 selector switch into this box?

I'd like to pick up one of these but I want an ammeter for precise control as well as a 3 selector switch (two elements with off in the middle) to switch from one element to the other.

 

[doug293cz]

How does one wire an ammeter and a 3 selector switch into this box?

I'd like to pick up one of these but I want an ammeter for precise control as well as a 3 selector switch (two elements with off in the middle) to switch from one element to the other.

You're going to need a bigger box. You'll need two contactors, a three position (on-off-on) switch, and the ammeter at a minimum. Assuming 240V operation, one hot line gets connected to one input terminal on each contactor. The other hot line connects to the SSR power in. The SSR power out goes thru the coil on the ammeter, and then connects to the other input on each contactor. The outputs of the first contactor connect to the first heater, and the outputs of the second contactor connect to the second heater. One on position of the 3 way switch powers the coil of the first contactor, and the other on position powers the coil of the other contactor.

Might be cheaper and easier to get two of these controllers, one for each heater.

Brew on

 

[mendozer]

This is the typical wiring I see on SD forums. Where does the switch, ammeter, and contactor fill in? What exactly is the contactor? I've seen a ton of wiring diagrams and I don't know what's needed or the order of them. My learning in electricity stopped at high school physics.

Does anything special have to happen for adding a 120V outlet as well for my pump?

And I priced the parts out and it's still cheaper I believe to get the stilldragon kit and go from there. I would get the larger box as well. HxWxL: 3.75"x7.25"x10.38"

 

[doug293cz]

This is the typical wiring I see on SD forums. Where does the switch, ammeter, and contactor fill in? What exactly is the contactor? I've seen a ton of wiring diagrams and I don't know what's needed or the order of them. My learning in electricity stopped at high school physics.

Does anything special have to happen for adding a 120V outlet as well for my pump?

And I priced the parts out and it's still cheaper I believe to get the stilldragon kit and go from there. I would get the larger box as well. HxWxL: 3.75"x7.25"x10.38"

Here's a schematic of how to switch an SSVR (what the StillDragon controller is) between two different heating elements:



If you don't understand the drawing, or how to actually implement the wiring, you should contact an electrician (or someone else knowledgeable.) Electricity can kill you if you get it wrong!

A contactor is an electromagnetic relay designed for switching high currents. They are activated using much smaller currents than they are controlling. The contactors for this application would be Auber Instruments CN-PBC302-120V (http://www.auberins.com/index.php?main_page=product_info&cPath=2_31&products_id=129), or similar. To control the contactors you need a three position, ON-OFF-ON switch like the Auber SW3 (http://www.auberins.com/index.php?main_page=product_info&cPath=7_32&products_id=235). Using this type of switch insures that you cannot connect the SSVR output to more than one heater at a time.

A 4 A slow-blow fuse will handle the contactor coil currents and a typical Chugger pump. You want a slow-blow fuse as the pump motor starting current is usually higher than the running current.

The Black, Red, and Purple hot wires, and the ground wires for the heaters all need to be 10 gauge stranded in order handle 30 A safely. The Hot Pink hot, and Gray neutral wires can be 14 or 16 gauge stranded as they don't have to handle more than 4 amps.

In order to have 120 volts available in your control box, the input power feed needs to be 4 wires (2 hot, 1 neutral, 1 ground). Without the neutral, you cannot have 120 V available.
This power feed should be protected by a 30 amp GFCI breaker or spa panel (which has a GFCI breaker.)

I forgot to add the ammeter to the schematic. Maybe I can get that done tomorrow.

Brew on

 

[doug293cz]

Ok, I updated the schematic to show how to connect a volt/ammeter.



Here is one suitable volt/ammeter: http://www.amazon.com/DROK-Multimeter-Measuring-Resistors-Transformer/dp/B00DVH64HW/?ie=UTF8&qid=1427223206&sr=8-3&keywords=digital+ammeter





The connections to the meter can be fine gauge wire, as they carry essentially no current.

Brew on

 

[mendozer]

Thanks! I don't get all the squiggly lines but I know someone who will haha.

That helps me get a parts list together. Think this will all fit in the larger box?

Also, my pump plugs into 120 AC plug (it's the tan little guy with AC adapter). Does the wiring change or would I just put an outlet where you see pump on there?

and is the potentiometer the blue box under the SSVR?

 

[doug293cz]

Thanks! I don't get all the squiggly lines but I know someone who will haha.

Good! Based on your questions, you need some guidance from someone more knowledgeable. It's for your own safety.

That helps me get a parts list together. Think this will all fit in the larger box?

I don't know how big that box is, or how big each of the component parts is, so I can't tell you if they will fit. Anyone who has built a control box will tell you that cramming everything into the smallest possible box will make it much more difficult to wire and service, and it will require service at some point. So, it's best to plan for that now.

The specific parts I linked are not the only options. They are examples of parts that are suitable for the job. Any part with equivalent specs should also work. You can often find cheaper parts on e-bay than the sources I linked.

Also, my pump plugs into 120 AC plug (it's the tan little guy with AC adapter). Does the wiring change or would I just put an outlet where you see pump on there?

Yes. People normally wire to an outlet in the control box, rather than hard wiring to a pump. Makes life easier.

and is the potentiometer the blue box under the SSVR?

The blue lines represent wires. The zigzag black line with an arrow touching it is the standard schematic symbol for a potentiometer (a variable resistor.)

Brew on

 

[mendozer]

ok cool thanks. I'll try to finalize design plans and should I require more help maybe I trade you for help since we're both in Renton. Beer for electrical counseling? sounds like good ol fashioned bartering

 

[Paps]

subd

 

[doug293cz]

@mendozer:

You might want to look at this thread: https://www.homebrewtalk.com/f170/modifying-still-dragon-controller-521911/#post6790339. Couple of other guys came up with switches that would allow you to switch the output of the SSVR directly and not have to use contactors.

Brew on

 

[mendozer]

oh so you need this "changeover" switch rather than a simple 3 way switch like SW3 from Auber?

 

[mendozer]

ah ok so the contactor handles the full 240 for the simple switch where this changeover switch handles it all. Is that right?

seems like just go with the cheaper option if they both do the same job. Auber's 30A 240v contactor is 16.50 so it seems better to just go for the switch. Less parts = less to go wrong, eh?

 

[doug293cz]

ah ok so the contactor handles the full 240 for the simple switch where this changeover switch handles it all. Is that right?

seems like just go with the cheaper option if they both do the same job. Auber's 30A 240v contactor is 16.50 so it seems better to just go for the switch. Less parts = less to go wrong, eh?

Yes, a 2 pole, ON-OFF-ON switch that handles at least 30A and 240V does the job of 2 contactors and a lower current ON-OFF-ON switch.

Brew on

 

[mendozer]

any experience with these Chinese changeover switches and the breaker mentioned in this thread with their longevity? Don't wanna die to save a buck

 

[Call_Me_Tex]

any experience with these Chinese changeover switches and the breaker mentioned in this thread with their longevity? Don't wanna die to save a buck

The only one I saw linked there that has high enough current (amp) capacity to directly switch is the amazon one...

http://www.amazon.com/dp/B003A3W41C/?tag=skimlinks_replacement-20

The down side to this is that you will always have a hot line going to each element. As long as everything has a proper ground and your GFCI is installed correctly you should be fine from a safety perspective. It should be as reliable as any household switch. I switch my lights on/off far more frequently than I use my brew panel and usually only have to replace them when we paint, not from failures.

 

[doug293cz]

The only one I saw linked there that has high enough current (amp) capacity to directly switch is the amazon one...

http://www.amazon.com/dp/B003A3W41C/?tag=skimlinks_replacement-20

The down side to this is that you will always have a hot line going to each element. As long as everything has a proper ground and your GFCI is installed correctly you should be fine from a safety perspective. It should be as reliable as any household switch. I switch my lights on/off far more frequently than I use my brew panel and usually only have to replace them when we paint, not from failures.

That Bryant switch is double pole, double throw, center off, so it can switch both hot lines at the same time. No power to either element when switch in center position.

Can you explain why you say that the ebay rotary switches, that claim a 32A @ 277VAC rating, are inadequate? Is there something in the detailed specs lower on the page? I looked at them, but couldn't make sense of some of the numbers.

Personally, I would trust the Bryant switch, and avoid the ebay rotaries just because they don't look robust enough to handle the current.

Brew on

 

[Call_Me_Tex]

That Bryant switch is double pole, double throw, center off, so it can switch both hot lines at the same time. No power to either element when switch in center position.

Can you explain why you say that the ebay rotary switches, that claim a 32A @ 277VAC rating, are inadequate? Is there something in the detailed specs lower on the page? I looked at them, but couldn't make sense of some of the numbers.

Personally, I would trust the Bryant switch, and avoid the ebay rotaries just because they don't look robust enough to handle the current.

Brew on

Man was I way off on both counts... that's what I get for trying to sneak onto HBT between meetings at the office. I obviously wasn't paying attention.

 

[mendozer]

Man was I way off on both counts... that's what I get for trying to sneak onto HBT between meetings at the office. I obviously wasn't paying attention.

So the Chinese switch can handle the load well?

What would happen if the switch failed? Would it just be stuck open (no current) or would it fail in the closed position and have electricity running to both elements tripping my circuit?

Either way, would it be damaging or is it one of those "ah well blew a circuit, just flip the switch and reset it" methods?

I don't mind paying the extra 18 bucks, but I like the rotary style switch better. It fits our controller boxes and designs better.

 

[doug293cz]

So the Chinese switch can handle the load well?

What would happen if the switch failed? Would it just be stuck open (no current) or would it fail in the closed position and have electricity running to both elements tripping my circuit?

Either way, would it be damaging or is it one of those "ah well blew a circuit, just flip the switch and reset it" methods?

I don't mind paying the extra 18 bucks, but I like the rotary style switch better. It fits our controller boxes and designs better.

High voltage, high current switches can fail by the contacts getting welded together. This means they would be stuck closed (on), which could create a dangerous situation. It's unlikely that it could fail in a way that would have both sets of contacts on. The resistance to contact welding depends on the contact materials and geometry. I have no idea what's inside the ebay switches, so cannot comment further.

Brew on