aquenne said:
You do not need two separate lamps. If 1 of the relay fails in the closed position both of the lamps will light up. There will be a path from 1 hotline through the element and to the other lamp and then to neutral.
Another E-brewery design 1 PID, 2 Elements, 4 SSR's
- Thread starter aquenne
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You do not need two separate lamps. If 1 of the relay fails in the closed position both of the lamps will light up. There will be a path from 1 hotline through the element and to the other lamp and then to neutral.
Actually, yes good point. A single 120V pilot light on either line to neutral would tell me there is voltage present.
aquenne said:
If you choose to do this be mindful of what kind of lamp you buy. I use 120v neon indicator lamps on my system. SSRs Leak a very small amount of current even when they are open.
The leakage current is enough to make a neon lamp light up. And it will confuse the hell out of you.
Amber Pilot Lamp | Princess Auto
these were the pilot lights i was planning on using elsewhere in the system.
they are neon as well.
these were the pilot lights i was planning on using elsewhere in the system.
they are neon as well.
thargrav
Well-Known Member
The reason it's unsafe is it only takes 50 volts and very little current to kill you. Sure, the heater won't be hot but you will have 110VAC between every "live" wire and ground when one SSD fails. Plus you will have a full 220 VAC across the SSD that's off.
So it's better to use only one SSD and a main contactor or breaker at power input to the box. This way you always know what voltages to expect, you know you have 110VAC between every "live" wire and ground, and you won't accidentally grab onto something live.
And as far as unplugging the power cord goes? A dryer plug doesn't unplug easy and it won't take too many unplug cycles to decide to leave it plugged in while cleaning, particularly if you have to reach under or around something to unplug the cord.
Install a main breaker, disconnect or contactor on the box power input!
If the SSR's are operating correctly the system is as safe as it could be with a contactor.
If an SSR fails with the contacts closed. I will have an audible alarm wired as well as a pilot light to alert me that there is voltage present, at the heater when there shouldnt be.
Bottom line, im not designing this system for sale, im designing it for my own use.
And just out of curiousity, how often are you guys getting failed SSR's?
If an SSR fails with the contacts closed. I will have an audible alarm wired as well as a pilot light to alert me that there is voltage present, at the heater when there shouldnt be.
Bottom line, im not designing this system for sale, im designing it for my own use.
And just out of curiousity, how often are you guys getting failed SSR's?
![Craft A Brew - Safale BE-256 Yeast - Fermentis - Belgian Ale Dry Yeast - For Belgian & Strong Ales - Ingredients for Home Brewing - Beer Making Supplies - [3 Pack]](https://m.media-amazon.com/images/I/51bcKEwQmWL._SL500_.jpg)
https://www.homebrewtalk.com/f16/contactors-e-brew-heating-elements-273489/
Have 2 left for you.....all you need is a selector switch. And shipping price to Canada is fairly reasonable.
Have 2 left for you.....all you need is a selector switch. And shipping price to Canada is fairly reasonable.
I had one fail on me after a year (appx 20 batches I guess). I chalked it up to the fact that my control panel had NO ventilation and the SSR got pretty hot while in use.
When I replaced the SSR, I cut a couple of holes in the box and mounted two small fans in it to blow air across the SSR heatsinks. time will tell if this helped.
Lucky_Chicken
Well-Known Member
related question... if your SSR fails how to you finish the brew day?
In that particular case, I didn't finish. I really never got started. I discovered it was bad while heating up water at the start of the day. I had things set to heat water to 165 or something and when I looked at it after milling grain, it was up at 185 and climbing.
I had a friend in the process of slowly building his system, so I bummed an SSR off him the next day and brewed.
When I ordered my replacement SSR, I bought several of them. If it ever happens to me again, I can shut the system down and swap out the SSR (about a 5 minute job, max).
kal
Well-Known Member
IMHO they are junk (brittle/fall apart). I looked at the princess auto switches and lights back when I first designed my setup.
So you're going to watch these pilots lights 100% of the time you're working on something that you consider dangerous and then quickly pull your hands out if one of the lights all of a sudden turns on?
SSRs don't just fail by not turning on or off when you go to turn them on or off, one could all of a sudden turn on or off.
Having an audible alarm to let you know when one SSR fails without the alarm being on whenever the element's firing normally requires some extra circuitry. You basically have to recreate this sort of logic:
If (PID is not firing) AND (voltage is present at element) THEN Turn on audible alarm
To do this would probably require an extra relay or something to latch.
You can't just wire the audible alarm like the pilot lights as otherwise it would constantly cycle on and off as you used the system. Very annoying.
Yup. You can do whatever you want.
The only reason I'm bringing up stuff is because you seem to think that the extra steps you're taking are going to make your system safer and I don't agree so I'm cautioning you to be careful.
I'd feel better if you said "I'm not putting anything extra in there and understand the dangers and will be careful".
A lot of people wire up elements directly with one SSR driven off a PID such that one side of the element is aways live. That's fine as long as they understand what they've done and use it accordingly.
Kal
thargrav
Well-Known Member
I wonder how many are attempting a build without a heatsink?
