Solid State Relay Conversion

[Bill Kielb]

1 hour ago, Benzine said:

What is the relationship, between the new relays and the ability to use the nitride shelves?

The solid state relays really stand on their own as something with several firing advantages and virtually no relay replacement later on. One of the characteristics of solid state relays is if they do fail, they can get stuck in the on position. Kilns with solid state relays and upper end kilns  often have a lid switch installed so anytime the lid is open all power is disconnected from the elements

Bonded nitride shelves conduct electricity but ....... glaze  does not stick them.  Basically they  get brushed off to clean them which means if we can find a safe way to use them they are great for a studio environment.. 

@neilestrick

shelf cleanup is a huge hassle and often requires excessive grinding and lots of kiln wash. The grinding is significant and we would soon destroy the core light shelves and back to having a bunch of gouged shelving to load in the kiln. Literally we have member volunteers assigned to clean these weekly and kiln wash them. Of course a decent coat or two of kiln wash needs time to dry so our glaze area is constantly stacked with shelves to be cleaned or fresh wash that is drying. 

So the relay upgrade will improve kiln performance in a number of ways but as a result of the additional safety allows the use of shelves that glaze will not stick to. There I think I got it all said in one spot!

This is an all volunteer organization so anytime I can make tasks that I can perform easily but are difficult for most members or difficult physical task such as grinding shelves,  I try and get them to a point where the the tasks are simpler or self sustaining. My technical background is significantly broad, most folks are here to practice their art.

[Hulk]

Bold and highlight lid switch over remembering to check power (truly) off before reaching in there... 

   ...for those contemplatin' replacing their mechs or otherwise adding SSRs to their site which ain' got no lid switch...

[Mark C.]

Bill where are these relays coming from?and whats the cost.

 

[Bill Kielb]

7 minutes ago, Hulk said:

Bold and highlight lid switch over remembering to check power (truly) off before reaching in there...

These are commercial kilns so the power is never turned off while people load and unload. The lid switch is one of the few dependable ways to ensure that the power is mechanically turned off when the lid is open. The switch is wired as fail safe in that the safety circuit must be made in order for power to be applied meaning an independent normally open circuit must be maintained.   Any defect in the  switch circuit means no power to the relays. Normal (high end) practice is for two lid safeties  in series interlocked with the controller start / stop output as a third form of safety. Any of the three devices not made will lock out the power. In this way there is electrical and safety circuit redundancy

Its a bit more foolproof than simply asking folks to turn off the power before loading and unloading. Most folks in a commercial environment don’t have an easy form of disconnect or often it’s a high amperage plug so  constant unplugging is not practical,or good for the plug. Turning  off the power ends up being difficult and causes them to temporarily lose their programming capability. A nice practice to be sure, but rare to find anyone doing that in reality.

[Bill Kielb]

8 minutes ago, Mark C. said:

Bill where are these relays coming from?and whats the cost.

 

Definite purpose contactors  (3 phase) will come from an automation supplier and be located in the machine upstream of the element relays and interlocked to a low voltage control relay driven by the safety circuit  powered by the on / off  / error function of the V6CF.

Any failure or open condition  of any of the safeties locks out the power. Power for the circuit is derived from the V6cf so error or non execution of a program firing locks out the power to the contactor and relays driving the elements.

i think that’s what you are asking 

total initial cost looks like about 300.00 bucks in parts first time only.

[Min]

2 hours ago, neilestrick said:

Also, I've got 500+ firings on some of my Corelite shelves and have never flipped them. They're still as straight as the day I bought them.

From my scrap kiln shelves pile, a couple Corelites  warped, 20" square. All of them warped. Glad yours haven't warped, maybe something with the size of the shelves? 

[Dick White]

This has been an interesting discussion. Let me add some things from my experience using Advancers in our gas kilns for the past 8-10 years. Most glaze blobs will pop off with a stiff putty knife, but there will be lots of other little stuff that will need to be removed with an abrasive because there isn't enough to get the edge of the putty knife on. We use an old worn down green grinding wheel held sideways on the shelf and rubbed in circles over the entire surface of the shelf. Five or 10 seconds per shelf is usually sufficient, and since it is hand work, there isn't the cloud of dust floating out through the neighborhood from the angle grinder. The only problem area is from the shelf posts. The material of shelf posts tends to bind to these shelves, so after a few firings there will be these little mounds of hard detritus wherever a post would sit, resulting in a rocking post. Both tops and bottoms of posts will stick, compounded by flipping and rotating, and so with our rectangular shelves, we had 6 permanent little mounds on each side. Those need to be ground off with the angle grinder, but we find the ordinary masonry grinding disks to be adequate, no need for the diamond cups. We have alleviated the problem  with a light coating of kiln wash applied to the ends of the posts and usually only need to refresh that once a year.

[neilestrick]

4 minutes ago, Min said:

From my scrap kiln shelves pile, a couple Corelites  warped, 20" square. All of them warped. Glad yours haven't warped, maybe something with the size of the shelves? 

Interesting. Mine are 14x28.

[Bill Kielb]

10 minutes ago, Dick White said:

This has been an interesting discussion. Let me add some things from my experience using Advancers in our gas kilns for the past 8-10 years. Most glaze blobs will pop off with a stiff putty knife, but there will be lots of other little stuff that will need to be removed with an abrasive because there isn't enough to get the edge of the putty knife on. We use an old worn down green grinding wheel held sideways on the shelf and rubbed in circles over the entire surface of the shelf. Five or 10 seconds per shelf is usually sufficient, and since it is hand work, there isn't the cloud of dust floating out through the neighborhood from the angle grinder. The only problem area is from the shelf posts. The material of shelf posts tends to bind to these shelves, so after a few firings there will be these little mounds of hard detritus wherever a post would sit, resulting in a rocking post. Both tops and bottoms of posts will stick, compounded by flipping and rotating, and so with our rectangular shelves, we had 6 permanent little mounds on each side. Those need to be ground off with the angle grinder, but we find the ordinary masonry grinding disks to be adequate, no need for the diamond cups. We have alleviated the problem  with a light coating of kiln wash applied to the ends of the posts and usually only need to refresh that once a year.

Pretty similar to our findings actually,  except in our case we have a hand stone that simply cleans up anything on the shelves with a few swipes, no real grinding. Most of the glaze simply pops right off and literally requires near zero effort. Other areas such as kiln posts require a few swipes of the Stone by hand. Literally for our gas kiln the shelf is handed to a team member that hand stones both sides lightly for about thirty seconds and it is put away.

For the electrics - cone six, I believe this will be as easy or  easier than our cone ten stuff.

[Mark C.]

(We have alleviated the problem  with a light coating of kiln wash applied to the ends of the posts and usually only need to refresh that once a year.)

Yes  with advancers posts will fuze a bit  and coating the ends is the cure-not sure about this at lower cone 6 temps-it happens at cone 10 for sure.

I have 3 sizes of spacers which also need coating . I use broken 5/16 advancer shgelve pieces and mullite 1/2 shelve pieces and 3/4 inch carbide shelve pieces for adding various heights to my posts as I load the 35 shelve avearge loads. If you do not coat these nets(thats what I call them) they fuze and will leave chunks(not the advancer pieces)

[mnnaj]

We have found ourselves with quite a number of posts that have schmutz on them so they don't sit flat.  Some of them have been ground down.  We now have a pile of posts of various heights, just off by 1/16" , give or take, from each other.  I'm toying with the idea of cutting the posts down to the next full inch to try to get them all the same size.   The formerly 5" posts to 4" ect...

Are there any suggestions on what kind of saw will work?  I have access to an older type miter saw and a table saw.  How about blades?

And being kind of new to the maintenance side of kilns and shelving - is kiln wash necessary on the ends of the posts for electric kilns that only fire to ^6?

Thanks, Nancy

[Bill Kielb]

That’s a lot of grinding, I would try a diamond tile saw (wet saw)  to cut.  it has worked for me when cutting old shelfs for spacers etc.... This  post started out as something about using bonded nitride shelves which resist glaze sticking to them.  @Mark C. mentioned that his posts did tend to stick over time so his answer was to kiln  wash the ends once per year or so. If they stick,  (Regardless to cone six or ten) then using his solution seems simple. If not there appears to be no need for it.

Personally I like his idea as we do this with our posts for our soda kiln even though everything gets wadding it makes cleanup much easier and is a simple quick dip of both ends of the post as needed  before it is put away after removal from a soda fire.

[Mark C.]

Wet diamond saw cuts posts like butter

you can use a dry masonry saw blade on a stationary saw but it’s dusty

consider cutting them down to 1/2 inch sizes as well

i used to fire 600 5 inch slip cast pots in a car kiln do I ordered 5.25 inch stilts custom made and they really saved space 

think outside the box

[ronfire]

A year old post but did Bill get the kiln converted to SSR and how much of a savings did it make? Longer element life?

 

[Bill Kielb]

59 minutes ago, ronfire said:

A year old post but did Bill get the kiln converted to SSR and how much of a savings did it make? Longer element life?

 

Never did.  As a volunteer free project I stayed away from It as the atmosphere became contentious. Anyone than knows me probably has received free help or designs or programming etc.... Never charged a penny for anything that benefits the greater ceramics community.  This can be good but also can be bad in that there are some that treat such free work as having zero value or less.  Anyway, did not feel right With too much risk involved for me,  but they would have saved a minimum on energy just because it allowed the use of lightweight shelves with increased safety.
I never could quantify the extra firings but used to get several more decent firings out of an element set by decreasing the standard relay timing from 14 seconds to 10 seconds so moving to  the SSR of 2 seconds should have given at least a handful of extra firings over the old mechanical relays.

Eventually I will retrofit one, it’s too easy and too economical. I have a couple starting their own studio and the reduced maintenance required will be a help for them starting up. We helped them set up a reduction monitor and they will use it to teach others. Nice folks, definitely worth helping them.

The  SSR video is still out there to show some of the things we consider when designing as folks asked if we could put together one so they could see for themselves.

 

[ronfire]

Thanks Bill, You posted this video on another thread started. Still thinking on changing my sitter. Cant decide  to do a wall mount with a mercury contactor or SSR but would then will still require a contractor for safety if the SSR fails . Is there a big advantage to an SSR with the Bartlett controller over a mercury contactor? With the mercury you would still require a pilot relay to drive it.

Could convert the kiln to 3 zone and SSR but by that time for a few more $$  I can get a new kiln, but then I still have the mechanical relay with most kilns.

The other problem is if I modify or build and something burns insurance would not pay out.

 

 

[Bill Kielb]

3 hours ago, ronfire said:

Thanks Bill, You posted this video on another thread started. Still thinking on changing my sitter. Cant decide  to do a wall mount with a mercury contactor or SSR but would then will still require a contractor for safety if the SSR fails . Is there a big advantage to an SSR with the Bartlett controller over a mercury contactor? With the mercury you would still require a pilot relay to drive it.

Could convert the kiln to 3 zone and SSR but by that time for a few more $$  I can get a new kiln, but then I still have the mechanical relay with most kilns.

The other problem is if I modify or build and something burns insurance would not pay out.

 

 

Sounds like modifying with SSR or relay has the same insurance issue actually. The mercury relay will last many many cycles. The SSR should last for an extremely long time as long as they are heat sinked well and the safety contactor will only cycle once per firing so it’s long lived as well. The only advantage to the SSR is its silent Operation  ........ and ....... can be cycled faster. Which is truly an advantage BTW.  The Bartlett controller is a nice convenience whether it drives an SSR or mercury relay.

I think the three zone kilns I looked at converting were 300.00 for two kilns with all the bells and whistles as far as safety’s, fuse holders, fast fuses to protect the  SSR’s, super oversized heat sink  etc.....  The point is correctly sourced, this becomes fairly cheap. I looked at it as a result of  relay failures which were  a hassle to the studio, and the occasional program change to squeak some more life out of worn elements till a new set came in.
They also got the benefit of changing their shelves to much thinner which saves  decent energy and of course no more kiln wash and shelf grinding which is  big for an all volunteer studio.

Not sure you have these same priorities though.

[neilestrick]

10 minutes ago, Bill Kielb said:

They also got the benefit of changing their shelves to much thinner which saves  decent energy and of course no more kiln wash and shelf grinding which is  big for an all volunteer studio.

Wy do you need SSRs in order to use Advancer shelves?

[Mark C.]

(Definite purpose contactors ) I use one in conjunction with my fire rite controller (its ramps the kiln up only)Its a dial that sets the on all the time in hours. All switches are on high always-the Definite purpose contactor does the switching. I have used two legs of a 3 phase one until it burned out now it a two pole unit at a higher amp rating so its hold up the test of time. These can fry pretty fast at upper end of there amp ratings

[Bill Kielb]

1 hour ago, neilestrick said:

Wy do you need SSRs in order to use Advancer shelves?

To ensure the kiln can never be energized since the shelves are conductive. Interlock through Bartlett safety and lid switch.  SSR’s can fail closed or have leakage so the normal fix is to have a contactor remove all power from the elements to avoid the possibility. 24v 65 amp contactor pretty cheap sourced corrrectly.

[neilestrick]

2 minutes ago, Bill Kielb said:

To ensure the kiln can never be energized since the shelves are conductive. Interlock through Bartlett safety and lid switch.  SSR’s can fail closed or have leakage so the normal fix is to have a contactor remove all power from the elements to avoid the possibility. 24v 65 amp contactor pretty cheap sourced corrrectly.

I see what you're saying, and I'm starting to remember a conversation we all had about this a while back. I don't think the use of silicon carbide/ Advancer shelves has to be specific to kilns with solid state relays, though. You could add a lid safety switch and/or safety relay to a kiln with mechanical relays, too, if you're concerned about possibly contacting a live element.

[Bill Kielb]

3 hours ago, neilestrick said:

I see what you're saying, and I'm starting to remember a conversation we all had about this a while back. I don't think the use of silicon carbide/ Advancer shelves has to be specific to kilns with solid state relays, though. You could add a lid safety switch and/or safety relay to a kiln with mechanical relays, too, if you're concerned about possibly contacting a live element.

Yes, you could but for the most part North American manufactures have saved that cost and hardware and are able to just state disconnect the kiln before loading and unloading.  As you are aware, occasionally mechanical relays stick closed as well so there is a small risk of electric shock there as well. Here we get away with an advisory to disconnect Before opening the kiln, Kilns produced elsewhere Often require lid safety.
The change to nitride shelves saved mass, cleanup and effectively would provide more available power for firing so the idea of changing to SSR with lid safety had a lot of pluses going for it in that studio environment.

The original complaint started out as the perceived hassle to replace relays as they failed and of course midfire failure puts everyone in a tither. So SSR longevity would reduce that occurrence to theoretically zero and have all kinds of other benefits in that particular environment. Ultimately there were a few  folks that expressed concerns and I decided to advise they buy a unit already made with SSR and purchase the shelving etc...  we had done the research on their relay issue and provided an alternate path That had some additional benefits for them. What started out as a money saving  good natured favor became too risky in the end. To this day they replace relays and complain about kiln wash and grinding shelves. Go figure!

[neilestrick]

11 hours ago, Bill Kielb said:

Yes, you could but for the most part North American manufactures have saved that cost and hardware and are able to just state disconnect the kiln before loading and unloading.  As you are aware, occasionally mechanical relays stick closed as well so there is a small risk of electric shock there as well. Here we get away with an advisory to disconnect Before opening the kiln, Kilns produced elsewhere Often require lid safety.
The change to nitride shelves saved mass, cleanup and effectively would provide more available power for firing so the idea of changing to SSR with lid safety had a lot of pluses going for it in that studio environment.

The original complaint started out as the perceived hassle to replace relays as they failed and of course midfire failure puts everyone in a tither. So SSR longevity would reduce that occurrence to theoretically zero and have all kinds of other benefits in that particular environment. Ultimately there were a few  folks that expressed concerns and I decided to advise they buy a unit already made with SSR and purchase the shelving etc...  we had done the research on their relay issue and provided an alternate path That had some additional benefits for them. What started out as a money saving  good natured favor became too risky in the end. To this day they replace relays and complain about kiln wash and grinding shelves. Go figure!

I just think we need to be clear to our readers that SSRs are not necessary to safely use Advancer shelves. Rather, it's the main power safety relay and lid switch, whether you have SSRs or mechanical relays. And if one is lacking the knowledge to do that, then just unplugging the kiln or shutting it off at the disconnect (if you had one installed when the kiln was wired up) will accomplish the same thing, although that relies on the user, whereas the lid switch does not.

[Bill Kielb]

3 hours ago, neilestrick said:

I just think we need to be clear to our readers that SSRs are not necessary to safely use Advancer shelves. Rather, it's the main power safety relay and lid switch, whether you have SSRs or mechanical relays. And if one is lacking the knowledge to do that, then just unplugging the kiln or shutting it off at the disconnect (if you had one installed when the kiln was wired up) will accomplish the same thing, although that relies on the user, whereas the lid switch does not.

I would agree and take it further that whenever changing to SSR’s a lid safety and definite shutoff is required because of the increased risk. Shelf change or not. It just also  happens to make using conductive shelves in an electric kiln more accceptable.

[ronfire]

Would there be a problem with adding an LED indicator light to the output of the ssr on the 220v side to monitor the output to the kiln or elements. I was looking at maybe one of these. I know if you run with the ssr it would have a short cycle time.