Relay Help

[George Stolz]

I'm trying to find a relay specified by the EE on the project I'm working on.

The part specified was:
"Sprecher + Schuh Part # CZE3-30S" (or maybe "-305")

I've tried google, yahoo, and found the manufacturer's website; but I am failing at finding the specific part number. I did find this in their catalog, which was the closest match I could find:

View attachment 723

I really don't understand why a pneumatic timer has been specified, there are no pneumatics associated with the system. However, the EE does repeatedly refer to the relay as a "pneumatic" timer, so I think the relay found is the one referred to.

The problem is, I don't believe the customer and the engineer are on the same page in regards to the "Last Man Out" switch in the room containing the X-Ray/Radiation machine, and am trying to figure out exactly what's been drawn and specified before I speak up.

 

[augie47]

If I understnad your question, part of your concern is the term pneumatic is used even thopugh there are no pneumatics. I this case, pneumtic refers to the menas that the relay used to "delay". There is an internal air chamber which bleeds down before allowing the contacts to "swap". I haven't actually seen one specified in years...electronics have somewhat taken their place,. I believe.

 

[mdshunk]

That's why God invented RFI's. Something like "Pneumatic timer CZE-30S does not appear to be in current manufacture. Please advice with regard to alternate substitutes." Perhaps you could even suggest the substitute in the RFI if you know what it is they're attempting to do with it. It's sort of a bummer they're suggesting weird brands, like S&S. Fine brand, for sure, but can sometimes be harder to source.

 

[George Stolz]

Yes, that was part of what I was unsure about, thanks - I thought perhaps there was a valve associated with the timer or something, it didn't make sense to me.

Would a pneumatically-delayed timer be better than an electronic one? Why would such an unusual part be specified (and manufactured)?

 

[mdshunk]

Would a pneumatically-delayed timer be better than an electronic one? Why would such an unusual part be specified (and manufactured)?

I think the EE is probably old-school. In the days before much solid state timers and PLC's, the timers were pretty much all pneumatic. They're sorta nice due to the fact that they don't really ever get "intermittant". When they fail, the normally just switch nearly immediately (spring a leak), instead of delaying. Maybe there can be a good reason to use a pneumatic timer still today, but I can't think of what one might be.

 

[augie47]

why

why

Yes, that was part of what I was unsure about, thanks - I thought perhaps there was a valve associated with the timer or something, it didn't make sense to me.

Would a pneumatically-delayed timer be better than an electronic one? Why would such an unusual part be specified (and manufactured)?

The EE is probably my age ................ may still wear spats

 

[George Stolz]

Perhaps you could even suggest the substitute in the RFI if you know what it is they're attempting to do with it.

After the last customer visit, I had (what I believe to be) a clear vision of how the customer intends for this aspect of the installation to operate, and I don't think the EE gets it. After the meeting, I was a bit puzzled as to how to get the system to behave the way the customer expects it to, there's small inherent difficulties involved.

Then I got my hands on the latest schematic from the EE and was relieved to see an answer - but on closer review, the basic principle behind the design aren't in line with the customer's idea, IMO.

It's sort of a bummer they're suggesting weird brands, like S&S. Fine brand, for sure, but can sometimes be harder to source.

I had a heck of a time finding what I found, I'm glad to hear that it is an odd brand.

I am planning to draw what I think would fall more in line with what the customer seems to expect, include the spec's for the relay, and hand it over to the foreman.

 

[George Stolz]

Here is what was originally spec'd, I drew it out to try to figure it out more.

View attachment 724

I guess my last statement under "Concerns" is not correct - the timer I found would run for 15 seconds, expire (closing the contacts), and then remain expired until the LMOS was shut off, right?

So, if the LMOS was left on for an extended period of time, and the doors are opened and closed, then there would be no timing going on - as soon as the doors are shut, the machine is ready to run, right?

(Edit to add: Here is the original drawing, I kept going crosseyed looking at it, I need more practice reading schematics. My drawing is an accurate representation of what the EE drew, right?)

 

[mdshunk]

The nice thing about doing engineered work is that you really don't need to put as much thought into the installation as you're putting into it. It's up to the EE to engineer the solution, and you to install it. If it doesn't work as the customer intended, you get paid to do it whatever way the EE draws up next. You're on the border line here of trying to play EE, and that's gonna get you in some serious trouble one day.

 

[cadpoint]

Last concern first, your door is "open till closed" to close the circuit it is not a case of.

...
During the fifteen second interval, it appears all gates and doors can be open an permit the opertion of the Beam / X-ray..

The time clock if electronic could do / apply all sorts of logic with-in itself not show. The Fifteen seconds could be a sum of events that need to happen and only controlled by the Logic of the clock, for example.

Think of it as a demand for service as, only once the conditions are met that the device will allow the application to procede.
A logic order of operation.

You might well be energizing the coil (OR think your energizing) but as the service is, your not going to get use of "fire button" (AKA interlock) till all the conditions of Normaling open must be closed for this to happen.

Ediited for Logic

 

[iwire]

You're on the border line here of trying to play EE, and that's gonna get you in some serious trouble one day.

I agree, keep the RFIs flowing.

The EE has been paid to do the engineering, you don't see the EE out at the job bending conduit.

 

[George Stolz]

Marc, I understand what you're saying. I am still trying to determine conclusively what the EE is asking for first off, and secondarily if it's doing what the customer asked for.

As much thought as I'm putting into it to simply understand where I'm being asked to land the wires, it made sense to me to compare stories at the same time to better understand the first part - if that makes any sense.

Does my drawing match his?

(Edit to add: Of course, I guess I've also made it clear I intend to offer a ready-made solution in the RFI to keep myself ahead of the game, too. )

 

[iwire]

secondarily if it's doing what the customer asked for.

Is that within your companies scope of work?

This is not a dwelling unit, there are specifications and scopes of work and responsibility.

Have you ever seen a 'responsibility matrix'?

You see them on jobs that have a lot of equipment. They will lay out who supplies, who stores, who moves, who connects, who supervises, who commissions, who warranties what etc.

 

[George Stolz]

I understand discretion, not stepping on toes, and not wasting time doing other people's work.

If I walk into the building in two weeks and see that a sprinkler pipe is broken, and dumping water at 500 gallons per minute into a five million dollar machine that the customer has purchased, I suppose I should not mention it to the GC because it's not in my contract to do so? :roll:

I am drawing pictures and thinking about this on my weekend, because I have five days next week to float over the floor guys, complete the control piping, wiring, and so forth, until by my contract my boss gets in trouble because we failed to meet a deadline. If I am standing on a ladder, scratching my head trying to figure out how this is supposed to go together on the spot, I am going to be wasting very very valuable time.

If the machine fails to safeguard the staff, and someone winds up infertile because the machine came on while they are still in the room, my company's work is going to be scrutinized closely - I intend to follow the chain of responsibility, and not deviate from the EE's directives; but if in the deciphering of the EE's design I make a mistake, or discover the EE made a mistake, determining who's responsible is not going to reanimate anyone's reproductive organs.

So, with that said: Does my drawing, which is my interpretation of the EE's drawing, match what the EE has asked for?

I apologize for my tone, but this is not the first discussion I've endured about "doing too much work", even if it's for my own damned benefit, and I think I've made it perfectly clear that I understand it's a big world and I'm an extremely minor player in it, and will behave accordingly. Nothing I say, feel, or believe goes directly to anyone of any consequence: everything I come up with is given to my boss, who is responsible for representing my company on site.

So any help with this is appreciated.

 

[electricman2]

Here is an old Square D pneumatic time delay relay I found in my shop. Anyone remember these? I used to work on and adjust these things. The screw on the bottom varied the time delay. This one is equiped with two DPDT switches rated 600V

 

[augie47]

timer

timer

remember them well...shows my age, huh ?
time was accurate to + or - 50% as best I recall... lol

 

[kspifldorf]

We've got 40 or so still in use. Problem free if accuracy is not an issue.

 

[mdshunk]

If I am standing on a ladder, scratching my head trying to figure out how this is supposed to go together on the spot, I am going to be wasting very very valuable time.

No, you're not, and I explain this with some reservation.

It's certainly noble that you're trying to figure this out on your own time. I wish I had 10 guys just like you. Bottom line is, when you're paid by the hour, you have the luxury of being able to turn your brain off until Monday morning. The time you spend on the ladder "scratching your head" is time that should rightfully be compenstaed for. It's not wasted time, unless you somehow feel your employer thought you already knew this stuff somehow.

 

[Bob Kraemer]

George,
When drawing motor control diagrams always try to do it in a ladder format.
Makes it easier to understand at least for me it does.
On the EE's drawing he writes the timer contacts are N/C then draws them N/O which they should be, he should note these contacts are delay on break.
R1 contacts are just latching contacts like on a motor starter.
Where is R2? Or is he calling the timer R2
It would seem to me the R2 interlock contacts should be in series with the R1 latching contacts or is there another relay that these are on that kills power to the common on the LMO switch

 

[George Stolz]

George,
When drawing motor control diagrams always try to do it in a ladder format.
Makes it easier to understand at least for me it does.

To be honest, I'm not quite sure what that means exactly.

On the EE's drawing he writes the timer contacts are N/C then draws them N/O which they should be, he should note these contacts are delay on break.

Do you mean, "He should note these contacts are delay on make." ?

I guess that gets down to my basic question with this drawing. Does the timer immediately energize, and then open the contacts after 15 seconds, or does it wait to energize until after 15 seconds?

Where is R2? Or is he calling the timer R2?

R2 is standing in place of where the machine's circuit expects to be run through doorjamb contacts. Instead of routing the door interlock circuit through the doors, it's being routed through the R2 contacts on the second relay ("R").

It would seem to me the R2 interlock contacts should be in series with the R1 latching contacts or is there another relay that these are on that kills power to the common on the LMO switch

The power to the LMO switch is not interrupted by any control, to my knowledge. It has power available all the time.