Hi all,
Since I have been on the topic of SSR's, I want to share more here related to the original ideal I had when I first started using them on VTTC's. This is from 2 past posts on a mail list I did back in early 2020 and late 2020 if I remember correctly.
So here is copy and pasted both:
Hi all.
Gave a hint on this earlier, in a different thread.
Starting a couple of weeks ago, I started to think about some things, while I was converting my "breadboard" interrupter to put in a case, I am always thinking, even when working on other things...
I used to work as printer on newspaper printing presses for a lot years. Just left this industry for good a couple of years ago now. Dying trade. Besides running them, also worked on them. Lots of mechanical and electrical controls involved. In addition, used to work on all kinds of support equipment in mailroom department, which handles the papers after they come off the press. Again all kinds of mechanical and electrical controls.
I started to think about rotary encoders on lots of different equipment we had. Then, I thought about SSR's (Solid State Relays), again on several different things.
SSR's have been around for quite some time now.
I started to remember, some types of SSR's have a zero cross trigger method. And it does this on the actual load, vs. the indirect method of the other 2 interrupters that I have modified and use on my VTTC's. Trigger on the actual load should be even better, since especially using a level shifted supply.
This should work I thought. Then I thought about an encoder to use. The ones on machines there were used for feedback. I thought, about an encoder that was more convenient to use and thought about CNC machines that I have run before in the past. They have a rapid handwheel rotary encoder. The big plus is these have mechanical detent stops between the optical slots.
So with just a little looking around, I found some very economical ones, just in case it does not work, so I would not be out much coin if I fail.
When I got them in, I did a couple a very basic encoder output tests scoping it. Looked at the pulse width times and decided it is most likely going to work.
Just another note, the detent stop is actually not "centered". Designed that way. At first I thought this was going to be a problem, then I realized it will not. Because of not being centered, when you initially turn the handwheel, because of the detent, one direction you get a "quick pulse snap".
And the other you get a "longer pulse snap". Instantly, after looking at the pulse width duration on the scope, I thought "burst mode" in the long one. Cool! And a single shot in the short one. Can also achieve bursts by a quick flick of short ones, not quite as intense.
Decided, since I was pretty confident, to put all of this in an enclosure from the get go, before even trying actually on the coil. Normally I would not do this, I would admit.
I must say, it is working greater than expected. Trigger timing is great. Long straight swords. No shorter wandering problems, like the EVR one originally had and even the former breadboard one had when using a level shifted supply. Really neat to be in full manual control. The things you can do are so numerous. A very fun controller. Get lucky once in a while right out the gate...
Since I was having so much fun, I have decided to give it a fun name, borrowing some from Greg Leyh's: Lighting On Demand big fellas coils :^)
So I will call it:
Swords On Demand
Just a few more thoughts here.
I suppose you could also use a regular encoder with a stepper motor and controller, or even fancier if you want, say a PLC or something else in conjunction with the SSR.
Also, I suppose using this SSR with several other numerous devices to supply a "drive" signal to it.
For me for now, I like the extreme simplicity of this setup. Just 3 economical parts and very easy to hook up :^)
But I just today earlier, received a second SSR, to play with...
Going to attach several pictures, some info, a quick crude drawing of the wiring, and a video of me running the coil with it.
Links:
https://photos.app.goo.gl/LDJkmHKtMqmHKg5f6Video:
https://photos.app.goo.gl/pxrJmxy9MttT1EHz6Chris Reeland
Ladd Illinois USA
Hi all,
I am resurrecting this post from much earlier this year since it is directly related to using SSR's and some related background info on my first try, which is near the bottom of this new posting.
As I hinted in one of my replies to Chip's question in his recent post: [TCML] Staccato Board, I am going to quote most of what I said again here:
"Anyways, I am pretty familiar with this circuit and others that are similar.
I have also modified this circuit a bit a while back. And another related one just a little. These are in my blue enclosures. I also have a very simple basic manual controller I put together a while back also.
Speaking of basic controllers, in the past few days off and on I have put together 2 more. Just bench tested right now. Will be doing VTTC running tests soon...to see if I failed or succeeded.
Anyways here is a picture of my collection of VTTC controllers.
https://photos.app.goo.gl/p9jpyod97xUi7UAi65 of them, with #6 in the works fairly soon I hope, which is based off the original design but some "layout" differences.
All of these controllers have zero crossing detection. Some different than others in how done.
I will be doing a new posting with pictures and maybe some video also eventually after doing some real running on coil with all 5 current controllers. Been a while since I have run the 304 VTTC so I want to run them all. Coil actually has a slightly damaged secondary currently, but still working ok with some losses...quite earlier this year I pushed it too hard, during extreme testing I did. Windings "buckled" in a few spots. Got too hot...the acrylic tube has warped some... Happens...not the first time :^) I will be fixing soon with some more ideas for major changes to this coil. I always seem to change this one around, testing/trying things.
Okay, enough rambling here...I will give more details eventually in a new post."
So picking up here now, I have run these 2 new controllers with success.
Going to call the new, very economical, encoder one: my "Mini" "Swords On Demand" controller :^)
I will let several pictures and a couple of videos speak for themselves. I make a few comments in the videos.
As can be seen in some pictures, I have removed the actual SSR from inside the original "SOD" enclosure and have now mounted on a piece on metal down low, to also help "shield" the circuitry inside it. This also allows me to share this SSR with several things. Can also easily switch back to my original tiny triac when using the "original" controllers which reside inside the blue enclosures.
I have also set some things up with some repurposed connectors I had laying around. They are arranged for ease of use and "genders" to avoid mistakes when switching between different controllers and different required "wall warts", to share components as much as possible.
I have also zoomed in pictures from much earlier this year of the current secondary coil damage. It is confirmed the secondary form is warped. I did not think/remember to take a picture of it when I removed the secondary to take a look inside of it to see why the windings "buckled". The epoxy coating can only do so much...
I will get around to repairing it. And I will also be completely changing the whole coil layout out. All major components the same. Just cleaned up and less cluttered and maybe well... "finalized" :^)
Link to pictures and 2 videos:
https://photos.app.goo.gl/FEBid6jNyapjDtoH8Okay, as I like to say, "enough rambling".
Make some "Sparkeys" if you can...
Chris Reeland
Ladd Illinois USA
