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Virgil Jones
07-30-2012, 03:37 PM
FINALLY!!

Early last year I decided my 100 Stadelman wasn't big enough anymore and saw how a friend had built a SIC furnace.
In February, 2011 I went to dinner with Pete at Rosen to discuss building a large electric furnace. Switched thoughts from SIC type to Moly after that discussion sank in...took a couple of months.
Between regular blowing, life, wife, and building the furnace, 1 1/2 years later I'm charging it.
I'll keep you posted on how the first charge goes.
Meanwhile, here's a link to photo-bucket pictures. I would recommend using the slide show option.

http://s1145.photobucket.com/albums/o511/virgilsfurnacephotos/

Pete VanderLaan
07-30-2012, 04:02 PM
Virgil, that is a great set of sequence shots of a major furnace build! No wonder it took so long!

So I'm curious, what do you think it cost in actual materials including the stuff that I did, all electric stuff and then how many hours do you think you have in that thing?

Really nice.

Guy Kass
07-30-2012, 04:56 PM
Really amazing to see. Thanks for going to all the trouble of shooting and posting the photos.

Guy

Virgil Jones
07-31-2012, 07:38 AM
Thanks, guys!

Pete, The closest I can figure on cost of materials is around 22,000.00. I had almost nothing on hand for materials to use. That cost includes things like plywood for the forms, random tools, cost of gas for trips to pick up materials (from 14 hours away, several 2-3 hours away, and untold amount of trips to local places). Some of the materials I used could have been replaced with cheaper ones, but I figure this is my last furnace.

It also cost 4000.00 to upgrade my studio electric from 200amp to 400amp and put in a designated 200amp/240 circuit.

As far as time goes, I have no way of knowing. The most time I spent consecutively is 14 days. Otherwise it was a week or a few days or a day when I could (and wanted not to have a life). Actually, that's misleading. I really enjoyed the project...most of the time. I started feeling like a shade-tree mechanic fixing up an old car. (here's your segue!!)

The time doesn't include all the time thinking about what was next and how I should do this instead of that, or change what I had already done, or the time researching ideas and materials. It also doesn't include cleaning the mess, which happens quickly in my small studio, so I could blow orders.

AS of today
I charged yesterday, and its working great.

Sunday night at 10pm I programmed the furnace to go from the normal running temp I use - 2120 - to 2300 in 8 hours.

Came in at 6am Monday and started charging with a tube...one 32 lb tube shot per charge. Since it was a new pot, the first three charges were 32 lbs each. Temp dropped after each charge 25 degrees and then rebounded to 2300 in 20 minutes. 1 1/2 hours between charges to flat and bright surface...really on these I checked with a punty.

The remainder of the charges where two 25lb tube shots every 2 hours...1 1/2 hours wasn't enough time between charges. Temp dropped 90dg and rebounded in 33 minutes (approx.) (the last charge was actually 60 lbs...I had a little left from an old bag...)
total charge was 410lbs. This definitely didn't fill the pot.

Set the cook cycle for 7 hours at 2325 at 10pm

This morning at 6:35am the cycle was set on the squeeze temp of 2000dg (for 3hours). The actual furnace temp at that time was still cooling down. I was 2165dg.

Virgil

Lawrence Duckworth
07-31-2012, 08:06 AM
Man...I enjoyed looking through the progress photos.!

I like the fresh air ducked cooling idea. Also the casting info was great (thinking about building a small 3 pot color furnace).

This dsesign might be perfect for multi pot use, ...what say you experts

Rollin Karg
07-31-2012, 09:23 AM
It's a very rewarding experience to build something. It makes even better when it turns out well and does what it's supposed to.

The next one will go easier, faster and will be better.

Pete VanderLaan
07-31-2012, 10:44 AM
I figured it would have cost that much. I periodically like to get reality checks on furnace pricing when done right. 22K is fair considering your time ( and mine) as well. I think I charged 24K for the last 19". The electric stuff is expensive.

It just looks great!

Scott Novota
07-31-2012, 01:09 PM
What happens to the 100lbs furnace?

Steve Stadelman
07-31-2012, 02:38 PM
Virgil, I really like what you have done there! :)

Rich Samuel
07-31-2012, 03:03 PM
Great documentation, Virgil! Have you thought of making a textbook?

Virgil Jones
07-31-2012, 06:47 PM
Thanks, everyone!
For now the old furnace is going to get maintenance, new pot, new crown if necessary, and then set aside for this fall as an emergency furnace if there's any problems with the new one. After that I'm not sure.
As far as the book goes...I think it's Steve's expertise and experience that's called for.

Rollin Karg
07-31-2012, 06:50 PM
Nicely done Virgil.

Pete VanderLaan
07-31-2012, 07:13 PM
Thanks, everyone!

As far as the book goes...I think it's Steve's expertise and experience that's called for.
***************
I think the electric part is the hard part but the documentation is really well done Virgil and it looks to be seriously solid in its construction.. I have been considering having a section of my book include the moly furnace but am genuinely concerned about the liability of doing it. Toxic chemicals are bad enough. You already know from last week how easy it is to make mistakes.

The hard part with Moly's is knowing what to do when something goes wrong. I tried to reduce the complexity in every way possible on your panel but even so, it builds up, layer on layer and starts to get pretty intimidating.

Virgil Jones
08-01-2012, 05:58 AM
***************
The hard part with Moly's is knowing what to do when something goes wrong. I tried to reduce the complexity in every way possible on your panel but even so, it builds up, layer on layer and starts to get pretty intimidating.

So, here's another layer of complexity that Charlie and I are thinking of...

The Partlow controller has an under temperature alarm that I would like to take advantage of. I would like to put a phone dialer on it to signal me if the temp gets less than 1950. There are power outages here that usually are only a few minutes....but, some are hours, and I've had a couple that were days. If I am called about the heat loss I can put a crash cart burner in the front door.

If I were to bring in a 120 line from a UPS on a separate 120 circuit from the rest of the panel and power ONLY the Partlow controller with it. Will it cause any problems for the operation of the SCR, Relays, etc? I can't think of what it could do that would be problematic. It would mean the controller would be on when the rest of the panel is not powered AND would be on when the rest of the panel comes back on after the power loss... Any thoughts.

Also Pete, when you get a chance, let me know about the six hole crown for my 100lber, the SCR fuses, and how to read/adjust the SCR.
Thanks, Virgil

Virgil Jones
08-01-2012, 02:29 PM
first day of blowing out of the new furnace.
A funny thing happened that I did expect, just not as much.
It took a couple of hours for my automatic body memory to stop going to, turning toward, or just wanting to go to the old furnace to gather.
It still happened a few times during the day after that.
I choose to call that dynamic body memory, rather than being stuck in a rut.

Also noticed the difference in sill height for gathering. 8 inches higher than the Stadelman 100lb or the old tank furnaces I used to have. This will be more interesting as I go lower in the pot.

Steve Stadelman
08-01-2012, 04:56 PM
Sill height was super important to me. I worked hard to keep it what I felt was the right height.

Pete VanderLaan
08-01-2012, 09:02 PM
How was the glass on a first melt?

Cecil McKenzie
08-01-2012, 11:24 PM
Virgil... I have seen photos of elevated platforms in front of furnaces that were of wood. I don't know if it was possibly just for comfort or possibly to address an issue of sill height. The sill on my furnace is pretty low and I like it that way.
My gas furnace is outside and my electric furnace is inside and when I change from one to another I do the same thing you are talking about, head for the wrong furnace. You will eventually stop doing that.

Virgil Jones
08-02-2012, 06:03 AM
Steve...I didn't see a way around the sill height without creating a pit in my studio floor. I wanted the air gap under the furnace to be 5" for my Roomba robot vacuum, the 2x2 frame, and the amount of lower insulation.
I'm very tall and figured if that wasn't enough I would do the platform that Cecil mentions. A friend in this area does that and just got used to the step.

Pete, the first melt had a few tiny seeds the day after the melt, but I didn't blow that day.

Yesterday, the first day blowing, the seeds were gone.
Also, I lowered my regular working temp. 20 degrees. I don't know if that's a result of reading a different S-type thermal-couple from the old furnace to the new, or the difference in furnace size, or what.

The bad news, which I expected, I had bits of frax and other unknown stones in the glass. Not much, but enough to cause some cording and probably some rejects when I get them out of the annealer. I cleaned out the pot as well as I could before heat-up, but, this is something that I've experienced every time with a new furnace and sometimes with pot changes on the old 100lber.

The other differences were the door was so easy to move that I had to get really gentle with it so it didn't bang, and I didn't have to charge after a full day blowing so I could blow today....YYYAAAA!!!!!! I've gotten so used to being tied to the studio charging several times per week that I almost didn't know what to do with myself!

Pete VanderLaan
08-02-2012, 06:10 AM
I wanted the air gap under the furnace to be 5" for my Roomba robot vacuum,
*************
Of course the old vacuum cleaner trick! I make mine so the entire Sears shop vac goes under it!

Actually, your floor is really thick which is what's pushing it up in the air. I think that floor insulation is the single most neglected thing in furnace design. What you can't ever see bleeds a lot of heat.

I find first loads of glass to always be kind of problematic for the reasons you describe and the second load to be the best glass you will ever have. It's all downhill from there on.

Steve Stadelman
08-02-2012, 12:42 PM
Don't take my sill comment as a criticism. I had to try to build a product that would be everything to everyone. You have made a really nice furnace. :)

Mark Rosenbaum
08-02-2012, 12:57 PM
Virgil: I just thought that you made it higher because you are basketball-player height! ;P

Virgil Jones
08-02-2012, 02:31 PM
Thanks, Steve, I didn't take it wrong. The 100lber has been a great workhorse, but, even that sill height would have been high for a gal I had working for me in the late nineties...I cut down a bench to what seemed to me to be floor high to fit her! When I sat on that bench I couldn't hear anything.

Mark, I'm that tall, but didn't make money at it. That's why I became a glass blower. I figured if I couldn't make the big bucks playing basketball, I'd make them blowing glass!!!

Michael Ahlefeldt-Laurvig
08-02-2012, 04:42 PM
I can see several good things in this furnace, but I dont understand a few things- first it looks like you are going to have to take down the whole front of the furnace to change the pot. Traditionally the gathering port stone and the sill part stays put and you take the pot out underneath those parts without having to move them. It looks like you have a door in the metal part of the front but how is that going to help you change the pot? The gathering hole is really huge, what is the reason for that? I feel the general size of the inside of the furnace is quite large, in proportion to your pot, Is it not so that keeping the volume/ inside surface area of the furnace down greatly reduces the energy consumption? It looks to me like its quite a span in your crown without having an arch? Whats your thoughts on this when designing it?

Pete VanderLaan
08-03-2012, 04:18 AM
but, even that sill height would have been high for a gal I had working for me in the late nineties..

***********
You should hire younger people.

Flat crowns suck actually but trying to put elements thru an arched one is certainly a challenge. Michael always tilted his pots forward so he could gather to the floor since he used these huge flat bottomed pots we used to ship to him in Denmark. If that port isn't tall enough, I suspect reaching the floor could have been a real issue.

Virgil Jones
08-03-2012, 07:33 AM
Michael…. I can see several good things in this furnace, but I dont understand a few things- first it looks like you are going to have to take down the whole front of the furnace to change the pot. Traditionally the gathering port stone and the sill part stays put and you take the pot out underneath those parts without having to move them. It looks like you have a door in the metal part of the front but how is that going to help you change the pot?

Yes, the entire front of the castable comes off. First the upper and lower sections of metal, then the frax and soft brick, then the upper cast door/wall (gathering port stone and the sill part) and the lower bricks. I didn't set it up with the gathering port stone and the sill part to stay in place because I wasn't confident that large of a cooked span of Kastolite-30 would hold up. The span would have been 29 inches. That is the interior diameter of the furnace to accommodate the 26 inch diameter pot. The 1 1/2 inch distance from pot to wall allows for 3/4 to 1 inch of space from wall to element, then element, then a little gap before the pot. YES, the elements are 4 inches ABOVE the pot. The little gap gives them drip room.

Michael...The gathering hole is really huge, what is the reason for that?

As Pete said, this allow me to get to ALMOST the bottom of the pot. The door opening is 12" tall and 10" wide.

Michael... I feel the general size of the inside of the furnace is quite large, in proportion to your pot, Is it not so that keeping the volume/ inside surface area of the furnace down greatly reduces the energy consumption?

The interior diameter and element room is as above. The lower portion which is the better material retention area (Morcocast99sfo and Kruzite 70 bricks) was figured to hold the volume of a full pot of glass.

Michael...It looks to me like its quite a span in your crown without having an arch? Whats your thoughts on this when designing it

Again, as Pete said, it's to accommodate the elements. I felt to create a hybrid arch crown with flat areas was beyond my ken. The crown is Kruzite Castable Plus -70% alumina - 3200F material. The flat areas are 5 1/2 inches thick and the rest is just less than 6 inches thick. This is way past the engineered specs for the material/span ratios. Since most of the heat is in the upper area of the chamber I figured it this way to err on the side of extra caution...hopefully. This also creates a huge heat-soaked reflector for the chamber similar to the "Thumb flywheel" (tm). ALSO, notice in the pictures the angles of both the front cast plate and the crown front. The front of the furnace castable holds up the front span of the crown.

Of course, time and pot changes will tell if things hold up.
As far as, energy costs go, I figured down time cost me more in lost orders than a little extra electric. AND, I've been charging the little Stadelman 3-5 time per week. This pot will charge once a week (less often in slower times per year). I'm hoping the electrical usage will be fairly close between the two furnaces considering the charging schedule difference.

Virgil Jones
08-03-2012, 11:06 AM
[QUOTE=Pete VanderLaan;106622]***********
You should hire younger people.

I finally got it! Good one!!!!

Virgil Jones
08-03-2012, 12:02 PM
Steve,
I posed this question earlier to Pete and haven't got a response. I know he's busy with a show.
Do you have any opinion on this?

"So, here's another layer of complexity that Charlie and I are thinking of...

The Partlow controller has an under temperature alarm that I would like to take advantage of. I would like to put a phone dialer on it to signal me if the temp gets less than 1950. There are power outages here that usually are only a few minutes....but, some are hours, and I've had a couple that were days. If I am called about the heat loss I can put a crash cart burner in the front door.

The land line normally stays active during a power outage.

If I were to bring in a 120 line from a UPS on a separate 120 circuit from the rest of the panel and power ONLY the Partlow controller with it. Will it cause any problems for the operation of the SCR, Relays, etc? I can't think of what it could do that would be problematic. It would mean the controller would be on when the rest of the panel is not powered AND would be on when the rest of the panel comes back on after the power loss. I know you didn't work with the Partlow controllers, but, I don't see an issue in this with the controller, just the other rest of the components."

Steve Stadelman
08-03-2012, 02:45 PM
I am really not prepared to talk about partlow. If it is merely a 120v switch functioning in alarm mode I don't see a problem but Charlie is the partlow guy.........sorry.

Charles Friedman
08-06-2012, 02:55 AM
I used to have a Partlow for many years ( now a Watlow) It also is powered by a separated 120 line.

It is easier to plug in an automatic call dialer from Radio Shack, into the answering machine, when every power goes out, it calls you, with a tone.

I try to stay away from too many tiny wires coming and going in a very small space.
If it is working fine, don't touch it, make your connection to the phone somewhere else.

Pete VanderLaan
08-06-2012, 07:19 AM
I put the Partlows virgil has under a separate 2 Amp fuse in the panel. They in turn are under a 15 amp breaker.

Virgil Jones
08-07-2012, 06:37 AM
Steve, Charles, Pete, thanks for the replies. I'll post what I've done when it's done. Looks like a couple of weeks for deciding how and installing a minimum use phone line. Line is $18.00 + taxes per month. Seems cheap for insurance.

Carlos Reckner
08-08-2012, 12:54 PM
Hi Virgil. First off let me say you have a nice looking funace there, and thank you for documenting the build so well.

On the subject of putting your controls on a UPS - it is actually good for them as the UPS will protect the electronics from surges and brownouts. That said here are a couple of things to watch out for when doing that.

Outputs from the controller or any other device should either be low voltage or sourced from the panel. In other words the signal to your SCR's is usually 4-20mA, 1-5Vdc, or 0-10Vdc. None of these will shock you. If you were to setup a relay output from the controller that used 110 sourced from the UPS then you can get a nasty surprise when the panel is off but the UPS is not. If the automatic calling device is just looking for a relay closure and it uses a low voltage signal then that would be ok. Also remember that as long as the controller is on it will be trying to maintain the temperature in your furnace. That means on an intermediately long power failure the PIDs are going to wind up which will slap the power on hard to your furnace when the power is restored (think 100% out most of the way back to temp). I am not sure about the Partlow controller that you have but it would be a good idea to bring in a digital input to put the controller in manual mode at 0% output when in power failure if it can do it. That will let the controller recover more "gracefully". If that is not an option then you can set up the power circuit for your furnace that will require an operator to reset it when power is restored. The down side to the second option is of course that someone would need to be there to reset the furnace.

Just a couple of thoughts from someone who has been designing and building industrial heat treating control systems for the last twenty years for what it is worth.

If you have questions you can PM me and I will get back to you, but please understand the rest of this week is really busy so it might be a day or two till I get back to you

Carlos

Virgil Jones
08-09-2012, 05:25 AM
Thanks, Carlos.
It's the kind of info I needed.
I'll be getting with Charlie Correll on this. He sold me the controllers and is setting up the alarm system.
I will PM you if needed, otherwise, I really appreciate the response.
Virgil

Virgil Jones
08-10-2012, 05:58 AM
Also remember that as long as the controller is on it will be trying to maintain the temperature in your furnace. That means on an intermediately long power failure the PIDs are going to wind up which will slap the power on hard to your furnace when the power is restored (think 100% out most of the way back to temp).

Carlos

This has we wondering about my 100lber furnace. With the Stadelman furnace and the Watlow controllers, what happens when a power outage happens?

The entire system is out, including the controllers. When the power comes back on does the controller "softly" start the elements up, or are they "slammed" with 100% power. Does it depend on the amount of temp drop, or other factors?

And, if moly elements ARE slammed with 100% power what does it do to the elements. I assume shorten their life span....which is a vague statement.

I have had many power outages of various lengths and never considered this.

Pete VanderLaan
08-10-2012, 07:52 AM
To the best of my knowledge, They aren't ever slammed. It's part of why they are used instead of simple relays. Yoou can always set your output on an SCR in AMPS anyways.

Steve Stadelman
08-10-2012, 07:53 AM
The S.C.R. In the 100 pounder has a four second soft start, no slamming.

Carlos Reckner
08-10-2012, 08:01 AM
Morning Virgil.

Usually when controllers are fully powered down (like a power failure) the units go through their normal startup routines and reset their PID loops to a 0% output. From there they usually ramp the output power value back up. This means it is a bit more "graceful" than a 100% power on startup. Now how fast the controller ramps the power back up depends on the controller configuration. If the controller uses the current temperature as the the start point and then ramps the temp back up the PID loops should react fairly normally. If the controller uses the last known setpoint (in other words the temp that it was set to before the power fails) then the PID loop will ramp up more aggresively. Basically in a nutshell the PID loop values look at the temp of the furnace (PV) and the setpoint (SP or SV) and calculate how much power is needed to get them to match. The farther apart they are the more it will react.

That is the short version of how the loops work. Either way if the controller is fully powered down it will have to ramp the power back up, so it will still be somewhat easier on the system. The only thing to note there is that if the controller is using the last know setpoint and the temp drops significantly the power will ramp back up to 100% and then try to get the furnace back to temp as quick as it can.

Carlos

Carlos Reckner
08-10-2012, 08:06 AM
Morning Steve. We cross posted. Good to know that you have your SCRs set up with the soft start options.

Carlos

Virgil Jones
08-10-2012, 09:00 AM
Morning Steve. We cross posted. Good to know that you have your SCRs set up with the soft start options.

Carlos

Pete, Is my quantum scr set up with the soft start?

Pete VanderLaan
08-10-2012, 09:35 AM
It's part of the function of an SCR. It defines it. Your particular SCR has an AMPS dial inside of the front plate of the unit. It's a tiny yellow dial. It is a hinged affair that I have attempted to describe to you. I set it at about 85% of the full turn it takes. I would be the first to admit that the documentation of that unit sucks. The price however was certainly right and it is functioning perfectly.

Steve Stadelman
08-10-2012, 09:50 AM
Yes it is. Any scr used in this application has to have it.

Virgil Jones
08-10-2012, 10:06 AM
It's part of the function of an SCR. It defines it. Your particular SCR has an AMPS dial inside of the front plate of the unit. It's a tiny yellow dial. It is a hinged affair that I have attempted to describe to you. I set it at about 85% of the full turn it takes. I would be the first to admit that the documentation of that unit sucks. The price however was certainly right and it is functioning perfectly.

Pete, Its good to know. I am getting an education. So Carlos' concerns are not warranted with the setup these furnaces have? I'm a little confused about Steve's statement that is has a four second soft start and how that relates to the power setting of 85%. Does this mean that my scr has a four second soft start because any scr used in this setting has to have it?

I did find (finally!!!) TWO tiny yellow screws in an very odd, but too obvious of a place!!! duhhh
There is also two dials on the front plate. One says " SFS " the other says "Max".

AND, so far the set up is working great! Thanks, Virgil

Carlos Reckner
08-10-2012, 10:07 AM
Virgil while your SCR has a soft start, I still would look into having any controller that is independantly powered through a UPS to have the PID loop zeroed out when the furnace is in power failure mode. Also if the controller is capable of ramping back to setpoint it is a better practice as the heat is introduced back into the furnace in a more controlled fashion. Now this may be less of an issue on small furnaces like these, and I will defer to Pete and Steve's experience on it, but the furnaces that I designed were large and powerful enough to tear things apart if we did not do these things. That said I still follow those design parameters even when working with the little ones as it is easier on everything inside the furnace.

Just my two cents worth

Carlos

Pete VanderLaan
08-10-2012, 11:05 AM
My stance is if it ain't broke, don't fix it. While I set the dial at about 85% of the total turn, that's not AMPS, it's just part of the turn of the dial. If we say 100 on the current limiting, that's 100 AMPS, a big difference. Watlow and your new one do it in completely different ways. The new one doesn't have all the bells and whistles of the big Watlows which I view as actually being better. Don't get all worked over it. It is set to work really well, yes?

Virgil Jones
08-10-2012, 12:52 PM
While I set the dial at about 85% of the total turn, that's not AMPS, it's just part of the turn of the dial.

Pete, it works great :-)
I'll un-wad my knickers...they actually weren't too bunched.
I am unclear what "just a turn of the dial" does. If it is adjusting amps, how do I read that? If it's not amps, what is it?

Carlos, one of the issues here is the duration of power outages. Most are only seconds or a few minutes. I'm still trying to find out if a manual reset is required to do what you suggest with my Partlow 1166. If so, that would be really inconvenient for 98% of the outages. My real concern is having the ability to get a "propane/venturi/burner-head crash cart" in place for longer outages. That's the idea of the phone dialer.

Carlos Reckner
08-10-2012, 03:20 PM
Wow I did not mean to start such a spirted discussion on putting a UPS on a control system. Just was trying to give you a heads up on some of the pitfalls that I have had to solve on heat treating furnaces that I have designed.

On short power outages the controller (seconds/few minutes) the controller will not even notice the hiccup. The furnace has enough thermal inertia to maintain its temp right through those. When the power comes back after a short outage the SCR will take its four seconds to come back to whatever output level the controller is asking for. In other words if the controller was requesting the SCR to be at 45% power the SCR would take four seconds to ramp its output from zero back up to the 45% out. What I was driving at was bringing the temp of the furnace back up after it had dropped from an extended power outage. Since you said earlier that you wanted the controller to trigger an alarm when the temp dropped below a threshold in the controller I (maybe poorly) assumed you were looking for when the temp had dropped a fair amount. At that point when if the power came back on the controller would be "wound up" at 100% output trying to bring the furnace back to temp. After the four second ramp in the SCRs the furnace would be going full out back to temp. Can they do that? Sure can. Is it hard on them? Depends on how far down in temp you are. All that said you have obviously been through many power outages with your current unit and I am assuming it is working fine so it may just be a non issue for you. On the units that I designed it was definitely an issue that we had to be aware of.

No matter how you decide to proceed I will still strongly recommend that you do not source any line voltage level outputs off of the UPS as this can be a safety hazard.

Carlos

Pete VanderLaan
08-10-2012, 03:39 PM
Pete, it works great :-)
I'll un-wad my knickers...they actually weren't too bunched.
I am unclear what "just a turn of the dial" does. If it is adjusting amps, how do I read that? If it's not amps, what is it?
.

********************

Turning that dial does increase the current flow and it does increase it in AMPS of 12 volt power rectified. My point is that the dial has been turned about 85 percent of its total possible revolution. So there are AMPS in reserve but it will just make the whole mess run hotter which it doesn't need. I built a boatload of power into that design. It should not need to be changed. One of the reasons that this SCR costs a ton less is that it is not loaded with a bunch of digital readouts. It is way simpler. If you want digital readouts, you should chuck this SCR and get a Power series from Watlow. Be ready to spend about $2,000 for it, maybe more since it is a high amperage system. My opinion is that the watlow gives you way more features than you need and it is very easy to screw with the programming to the point that it can only be reset at the factory.

It is working fine. Don't tweak the nose of your silicon Buddha.

Virgil Jones
08-12-2012, 09:56 AM
Even though I've been running the small Stadelman moly furnace for a few years, I've just know enough to push the right buttons and blow glass.
This has been an education...somewhat forced out of necessity...which is usually the case for me. I thought I'd share this SCR educational manual I found on the internet. It's fairly basic, but a good start.

http://www.chromalox.com/content/training-manuals/TM-PK501-SCR-power.pdf