LNL e23T-3 with Solid State Relay Option

[not a bot]

Hi,

 I would like to better understand how LNL implements their Solid State Relay upgrade for the e23T-3 Kiln.

It seems like a very pricey upgrade compared to some other Solid State upgrades I have seen, so I imagine there is some definite reason why, and it would be helpful to understand all the details.

I am a sucker for wiring diagrams and or schematics, if anyone knows where I might find one for an easy Kiln LNL Solid State Relay circuit I would appreciate a link.

Any other details you can share will also be helpful.

Thank you!

Edited June 25, 2022 by not a bot

[neilestrick]

The L&L system uses zero crossing SSR's, one for each section/circuit of the kiln. Each SSR switches one leg of the circuit. Both legs go through a mechanical relay that acts as a safety. Rather than using a heat sink, the system has a cooling fan that is controlled by Output 4 on the Genesis controller. Each circuit is fused. It's not overly complicated, but there's a lot more labor involved with the manufacturing. I don't know for sure, but I'm betting that they're essentially custom built at this point since it's not a common upgrade, laying out and drilling all the mounting holes for all the additional parts by hand.

I think an SSR system is really cool, but it's not going to be a big money saver by any means unless you build the system yourself. And even then, the cost of mechanical relays is so low that you won't save much since they last 300-400 firings in L&L kilns. The SSR's will increase element life, but nobody knows how much. I have yet to find any solid documentation on that. I built an SSR system on my new kiln last year, but I've only got about 100 firings on it so far, and I expect to get 250-300 firings from the elements even without SSR's, so I won't have any numbers for a couple more years.

If you've got the money, go for it! It's like tricking out a car- not necessary but totally cool. If you're hoping it will pay for itself, it won't. The Quad elements will definitely pay for themselves, so at least get those if you're getting an L&L.

[Bill Kielb]

10 hours ago, not a bot said:

Any other details you can share will also be helpful.

While not L&L here a video of some of the design considerations for SSR stuff. There is a huge spread in pricing of SSR’s as well, depending on name brand vs non. Passive cooling vs active cooling (fan) definitely a design thing (also uses energy with a fan). Zero crossing is good rather than switching at peak (approx 380 v), so a soft start for the elements each and every time. If you have ever turned on an old lightbulb and the fuse in the base popped you probably just turned it on at peak cycle and it was so worn it went over current in that instant. Old lightbulbs had fuses built into their base just for the occasion.

Faster cycle times so in theory better zone control and temperature maintenance. I think it’s pricey right now because of low demand, how robust the design is etc…. For example a passive cooled design can have user obstruction issues, hot kiln room problems. A fan even though it cost a bit, is probably more predictable and fits in a smaller profile. In theory the faster cycle time should allow worn elements to be used a bit longer, but each relay has some voltage drop across its junction - so that heat is not available to the firing.
https://youtu.be/AvdPwKuj6rM

 

[not a bot]

Thank you to both for providing such thoughtful answers.

"The L&L system uses zero crossing SSR's,"   - This seems like a great idea.

"one for each section/circuit of the kiln." - I have seen some smaller kiln wiring diagrams where one SSR feeds current to three relays, which seemed like an aggressive use of the SSR's current rating and safety factor..

"Each SSR switches one leg of the circuit." - ? Do you mean to say one SSR per positive and negative *leg* of the 240vAC, or was this just a casual way of reinforcing the previously stated benefit? I am not trying to nit pick, and will appreciate learning exactly what you had hoped to convey.

"Both legs go through a mechanical relay that acts as a safety." - I appreciate the idea of the mechanical relay acting as fail safe. 

"Rather than using a heat sink, the system has a cooling fan that is controlled by Output 4 on the Genesis controller." - Some of the other kilns I have looked at rely on a heat sink. It seems like an inexpensive fan would provide a lot of benefit at minimal cost. I am surprised that anyone would rely on just a heat sink when the circuit is intended for high current.

"Each circuit is fused." - another nice detail.

 

Thank you very much.

One additional benefit, one that appeals to me, is not having to listen to the relays clacking.

My father was an EE with a specialty in high current high voltage relay engineering, so I appreciate a good relay, but I find the clacking somewhat unnerving.

My wife has some tiny glass kilns, and when they chatter in the background I become abnormally preoccupied with listening for changes in pattern etc.

I will write to LnL and ask if I may view a wiring diagram. There seems no doubt that I will be impressed.

 

One last question. Is it reasonable to think that the controllers installed in an LnL are pre programmed to make best use of the SSR high speed switching or will there be a learning curve in terms of setting up programs etc.

Thank you!

Edited June 25, 2022 by not a bot

[neilestrick]

1 hour ago, not a bot said:

"Each SSR switches one leg of the circuit." - ? Do you mean to say one SSR per positive and negative *leg* of the 240vAC, or was this just a casual way of reinforcing the previously stated benefit? I am not trying to nit pick, and will appreciate learning exactly what you had hoped to convey.

Each element set is fed by two wires, either both 120V in the case of a 240 volts system, or one 120V and a neutral in the case of a 120V system. The SSR switches one leg while the other stays open via the mechanical relay. Because the mechanical relays only cycle at the start and end of the firing, in theory they should last as long as the SSR.

1 hour ago, not a bot said:

One last question. Is it reasonable to think that the controllers installed in an LnL are pre programmed to make best use of the SSR high speed switching or will there be a learning curve in terms of setting up programs etc.

There's a setting in the Genesis controller to turn the SSR function on. It will cycle the relays up to twice per second. There are no other setup requirements.

1 hour ago, not a bot said:

"one for each section/circuit of the kiln." - I have seen some smaller kiln wiring diagrams where one SSR feeds current to three relays, which seemed like an aggressive use of the SSR's current rating and safety factor..

I would prefer to break out each circuit with its own SSR. I don't love 3 wires coming off of one relay terminal, and with a larger kiln, using multiple smaller relays allows you to over-spec the SSR quite affordably. The cost difference between one large relay and three smaller relays is not much in the big picture. I'm also a fan of separating the circuits as much as possible because it make diagnosing problems easier, and preventing an issue with one circuit from affecting the others.

1 hour ago, not a bot said:

My wife has some tiny glass kilns, and when they chatter in the background I become abnormally preoccupied with listening for changes in pattern etc.

The silence is nice. If you get up close to the kiln you can hear it quickly cycling 'wah-wah-wah-wah'.

[Bill Kielb]

4 hours ago, not a bot said:

One last question. Is it reasonable to think that the controllers installed in an LnL are pre programmed to make best use of the SSR high speed switching or will there be a learning curve in terms of setting up programs etc.

Most controllers have a relay delay setting or one specifically for SSR. If it’s one of the variations of the Bartlett control it is a selection in the hidden menu. So just a few keystrokes, if you are moving from mechanical relays to SSR. For a new machine built with SSR it should be configured already. As far as a learning curve, the controller will do all the work in theory maintaining preprogrammed ramps etc….. so the user really would not have anything to do other than run their program.

[not a bot]

Thank you to both for such thoughtful and helpful replies.

[oldlady]

not a bot, it sounds like you just cannot accept the enormous amount of research and knowledge in the kiln builders approach to providing economical, safe and practical kilns to the public.   i really do not know any potters who would bother with all this fuss.   the preset programs work for a large percentage of potters.  figuring out how to set up a program for simple bisque and glaze firing when you really have no experience firing seems to me to be a lot of work for not much gain.  

buy a kiln, let your wife make pots not sit around waiting for you to find the perfect kiln that does what it does the way you want it to.   happiness is making pots and firing them, let her.  potters have been using kilns for many years  without worrying about these tiny details.