Non-dim setting good enough for movers?
- Thread starterChris Pflieger
- Start date
And while you are at that, does anyone know what High End Systems was thinking!!!
Amiers
Renting to Corporate One Fixture at a Time.
Less wires and pins. Equals more money saved or made however you want to view it.
Chris Pflieger
Well-Known Member
I think the problem started with "solid state relays" (SSR) being coined as a term for SCR based switching. Traditionally, I've used "air gap" as a safety related term to indicate that a relay is inline with the semiconductor and provides a true dead circuit when off. Of course, that relay doesn't bypass the triac, so for the application here, it's useless.
BillConnerFASTC
Well-Known Member
After some googling, I'm not sure air gap nor dry contact are the correct terms. The wet and dry may have originally been wet as in mercury or dry as in mechanical relays or switches, but a lot of people seem to now use it as voltage (wet) or no voltage (dry). Wikipedia definition for dry contact relay: "Dry contact may mean any of the following in electronics: No current: A dry contact is the synonym of volt free - it is not "wetted" by a voltage source. Dry contact can refer to a secondary set of contacts of a relay circuit which does not make or break the primary current being controlled by the relay."
Air gap seems more commonly associated with computer security - like no connection - wired or wireless - so really secure; or plumbing, like what is sometimes required for a dishwasher to prevent contamination by vacuum. As far as electrically, air gap definition by MW: an air-filled gap in a magnetic or electric circuit (as the space between the field-magnet poles and the armature in a dynamo or motor).
The only hit that suggests a electrical relay with contacts (like what many of us would know when we see it) is from Control Booth wiki.
And looking at data sheets, ETC's ThruPower refers to "mechanically latching relays" though a "mechanical held air gap relay" is slipped into the features list. The Sensor relay module data sheet does not use wet, dry, nor air, but just "mechanical relay".
I'm sure I've used "air gap" and "dry contact" but think as a result of this discussion I will change to "mechanical relay" which, when opposed to a "solid state relay", is perfectly clear. Or perhaps just "switch" is good, and note somewhere that it can be controlled by dmx.
Can we please return to T-20s and T-12s and Rs and PARs and Gs, please?
Air gap seems more commonly associated with computer security - like no connection - wired or wireless - so really secure; or plumbing, like what is sometimes required for a dishwasher to prevent contamination by vacuum. As far as electrically, air gap definition by MW: an air-filled gap in a magnetic or electric circuit (as the space between the field-magnet poles and the armature in a dynamo or motor).
The only hit that suggests a electrical relay with contacts (like what many of us would know when we see it) is from Control Booth wiki.
And looking at data sheets, ETC's ThruPower refers to "mechanically latching relays" though a "mechanical held air gap relay" is slipped into the features list. The Sensor relay module data sheet does not use wet, dry, nor air, but just "mechanical relay".
I'm sure I've used "air gap" and "dry contact" but think as a result of this discussion I will change to "mechanical relay" which, when opposed to a "solid state relay", is perfectly clear. Or perhaps just "switch" is good, and note somewhere that it can be controlled by dmx.
Can we please return to T-20s and T-12s and Rs and PARs and Gs, please?
Of your terms for traditional relays, Mr. Bill, I think I'm liking mechanical relays. Thinking back, I've installed mechanically latched mechanical relays and, more commonly, magnetically held mechanical relays with "holding contacts" electrically wired in parallel with normally open "Start" or "On" pushbuttons. Moving on to your T's, R's, PAR's and G's, I'll counter with A's, P's and S's. Please, let's not get back to gas, lime or brine filled dimmers although I have been involved with retrofits where I was removing asbestos jacketed single conductor wires from within pipes previously used to supply gas to gas chandeliers. This was when I learned the hard way about the joys of switched neutrals. Can I swerve this a little further?
Toodleoo!
Ron Hebbard. Edited to correct having included my salutation and name twice.
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IIRC, I first heard the term air gap relay used by @STEVETERRY , in the same speech/diatribe as his mythical "transition valve", which I keep looking for and can never find.
How about ice cube relay?
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Thinking about what? If talking about using XLR3 for DMX512, well, while not innocent, their position is arguably defensible/excusable. Intellabeams originally ran only on Lightwave Research proprietary protocol using XLR3 and mic cable just fine. Then when DMX512 became popular they realized a chip-change could easily allow the luminaire to be DMX-controlled. So what should they have done? Recalled every fixture in the field and changed the XLR3 to XLR5 when making it DMX-capable? Yeah, probably. But they didn't have the benefit of our hindsight. I forgive them. Better companies have made worse mistakes with connectors. AMX192 on Switchcraft TA-4, anyone?
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What most of the higher end manufacturers did was add 5 pin in/out connectors as well as 3 and most still do this.
High Ends problem was that would have required a modest re-design of a number of their fixtures to accommodate 3 & 5 and they were not willing to do that. Not sure it could be done on some of their units, thinking Studio Spots and Beams. Thus they made the bad choice of staying with 3 so as to not have shops with dual inventories of some 3 and some 5, which is understandable. Possibly cost them some sales though.
High Ends problem was that would have required a modest re-design of a number of their fixtures to accommodate 3 & 5 and they were not willing to do that. Not sure it could be done on some of their units, thinking Studio Spots and Beams. Thus they made the bad choice of staying with 3 so as to not have shops with dual inventories of some 3 and some 5, which is understandable. Possibly cost them some sales though.
Electromechanical relay is another term that is synonymous with mechanical relay, ice cube relay, and air gap relay.
And on the bit of high end systems, it would be much easier to have users buy tons of adapters and not have them all fitted with 5xlr. I'm curious to know how easy it would be to replace the 3xlr with a 5xlr.
And on the bit of high end systems, it would be much easier to have users buy tons of adapters and not have them all fitted with 5xlr. I'm curious to know how easy it would be to replace the 3xlr with a 5xlr.
From the perspective of idle curiosity, I'm curious as to the derivation of the term "ice cube relay" since when you energize the coil you're likely creating heat rather than removing heat. As to your High End 3 xlr / 5 xlr. These days so many manufacturers solder the rear side of their connectors directly to PC boards which would make swapping inserts a little more problematic.
Toodleoo!
Ron Hebbard.
You had to bring up the AMX192 on TA-4 debacle didn't you? And then to further compound the situation by not wiring contact number to contact number when eventually moving to XLR4's. Ya, you really can be a "curmudgeon".
Toodleoo!
Ron Hebbard.
BillConnerFASTC
Well-Known Member
I agree the four terms you note mean the same thing to many of us but not sure that either "ice cube relay" or "air gap relay" are generally accepted terms in wide use for these devices. Besides, there are solid state ice cube relays. I think the "ice cube" is more about mounting and form factor rather than electrical characteristics. Neither "all mechanical relays are ice cube relays" nor" all ice cube relays are mechanical relays is true."
I'm not sure but "electromechanical relay" seems like an oxymoron, as by many definitions, a relay is an electrically operated switch. Relay was good enough and accurate for a long time, till someone coined the term solid state relay. Perhaps the term NSSR (non-solid state relay) is needed.
JD
Well-Known Member
Don't like the term "ice cube relay." A SSR is cube shaped.
If it don't Click, your movers will be sick!
A big part of the problem was the introduction of the Solid State Relay. It was natural evolution that someone would pot a back-to-back SCR set, a firing circuit, and an optocuppler in a nice little mountable block that has a "coil" input and a "load" output and call it a relay. Doesn't matter if it's HVAC motors, large heating assemblies, or other large equipment, getting rid of the unreliable mechanical thing called a Relay and replacing it with a solid state device that can be mounted and connected up pretty much the same way as a mechanical relay was an advantage.
To the dimmer manufacturer, it was a blessing! No need for that pesky isolation and firing circuit! Just send it a little juice at the right time in the waveform and it works just as well...... But then there's that name.... Solid State Relay. Maybe they should have called it something else, but it was being marketed as a replacement for a relay! Darn!
The applications where it cannot be used as a relay are few and far between. Unfortunately, we are one of those "applications!"
If it don't Click, your movers will be sick!
A big part of the problem was the introduction of the Solid State Relay. It was natural evolution that someone would pot a back-to-back SCR set, a firing circuit, and an optocuppler in a nice little mountable block that has a "coil" input and a "load" output and call it a relay. Doesn't matter if it's HVAC motors, large heating assemblies, or other large equipment, getting rid of the unreliable mechanical thing called a Relay and replacing it with a solid state device that can be mounted and connected up pretty much the same way as a mechanical relay was an advantage.
To the dimmer manufacturer, it was a blessing! No need for that pesky isolation and firing circuit! Just send it a little juice at the right time in the waveform and it works just as well...... But then there's that name.... Solid State Relay. Maybe they should have called it something else, but it was being marketed as a replacement for a relay! Darn!
The applications where it cannot be used as a relay are few and far between. Unfortunately, we are one of those "applications!"
Chris Pflieger
Well-Known Member
Relays were also used very commonly in elevator logic boards, 10s of them for just a few floors and over 100 if you had more than a few. Now a days they're all done by computers. I till think that "older" technology is much more reliable. The model T didn't have as many issues as a 2005 honda pilot (curse you power steering and transmission!).
John Palmer
Well-Known Member
Studio Beam PC's have both 3 &5 pin XLR.
Technos & Cybers would have been really hard to fit with both.
I always thought it was because 3 pin XLRs are cheaper.
John
Technos & Cybers would have been really hard to fit with both.
I always thought it was because 3 pin XLRs are cheaper.
John
DuckJordan
Touring IATSE Member
I may be shooting in the dark here but does anyone have a picture of a scope of the wave form from a standard 120v outlet vs a dimmed circuit at 100% I'm trying to write a project grant and one of the things that has come up is "well why do we need to buy relay modules". Unfortunately anecdotal evidence isn't something a bidding committee cares about and I need solid proof about the difference between the two.
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A Google image search will return all manner of pictures and articles that explain SSR/SCR/Triac behaviour and what happens around the zero crossing. This article is pretty good. The section titled Solid State Relay Output Waveform covers some of the issues. It doesn't cover the impacts of an inductor in the circuit.
Frankly, your bidding committee likely isn't qualified to make a decision about whether to use a relay or a dimmer. The simple answer is "because the manufacturer requires it". The committee could hire a professional engineer to make such a determination but that would cost more than the relays and give the fixture manufacturers a good reason to void the warranty.
Frankly, your bidding committee likely isn't qualified to make a decision about whether to use a relay or a dimmer. The simple answer is "because the manufacturer requires it". The committee could hire a professional engineer to make such a determination but that would cost more than the relays and give the fixture manufacturers a good reason to void the warranty.
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