Mechanical delay.
Mechanical delay.
(OP)
Long ago I saw one of these but now that I could actually use one....nada
I want to prevent someone from starting a motor more often than every 15 minutes.(EVER!)
I have electronic timing so I can start a 15 minute timer that prevents hitting start again until it times out. But you get the clever/stupid operator who figures out that if power is lost the timer resets. Then they just crank off the disconnect and then back on, and away they go with a 30 second cycle.
I have seen mechanical bellows(?)types that essentially cock with the initial turn on then take x minutes, regardless of the power situation, to re-close.
Anyone have a lead, or know what these are called? Or have an effective alternate solution? Google bombed for me.
I want to prevent someone from starting a motor more often than every 15 minutes.(EVER!)
I have electronic timing so I can start a 15 minute timer that prevents hitting start again until it times out. But you get the clever/stupid operator who figures out that if power is lost the timer resets. Then they just crank off the disconnect and then back on, and away they go with a 30 second cycle.
I have seen mechanical bellows(?)types that essentially cock with the initial turn on then take x minutes, regardless of the power situation, to re-close.
Anyone have a lead, or know what these are called? Or have an effective alternate solution? Google bombed for me.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com





RE: Mechanical delay.
What you saw was a "pneumatic time delay relay" (aka pneumatic timer). You are correct in that they will work regardless of the electrical power condition. What you would want is an Off Delay version with NCTC (Normally Closed Timed to Close) contacts plus a set of NO instantaneous contacts. The NCTC contacts will change state immediately when the coil in energized, but will after the coil is de-enerized they will remain in that condition until the bellows lets all the air out.
The first time you give a start command, the command signal passes through the NCTC contacts to the timer coil, which also then seals itself in through the NO instantaneous contacts which were in parallel to the NCTC, which then also feeds the remaining desired control circuit. Once the run command is removed (ahead of this timer circuit), the coil drops out and of course the NO instantaneous contacts will open, but the NCTC contacts will remain open until the bellows allows it to re-close, which prevents the circuit from being re-energized.
Just so you know though, some electronic Off-Delay timers use retentive memory (through a super cap usually) and will maintain their condition regardless of power status as well, effectively duplicating the action of a pneumatic timer. In the electronic timer world, it will be referred to as "Off Delay Without Auxiliary Voltage"
RE: Mechanical delay.
Everyone used to make them. Square D, GE, Allen Bradley, Westinghouse, Cutler Hammer, Telemechanique.
The Cadillac was Agastat. They had a dial calibrated in seconds or minutes. This feature saved a lot of time on startups. The others had numbers that did not corelate with time. You may spend 10 minutes or more setting a 2 minute delay on most of the other timers.
Respectfully
RE: Mechanical delay.
I am going to take a run at the electronic ones because... I'm an electronics type of guy!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
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By the way Keith, had your user not bought that el-cheap-o soft starter, this lockout function would have been a simple programmable setting. Not bad for you though, assuming of course you can get paid to provide the solution in external logic!
RE: Mechanical delay.
But to-wit, how would a classy SS hold that time thru a power cycle? Or would it just look at its internal temperature and keep itself thermally locked out, since that is the crux of the matter anyway?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
Yow, they are pricey aren't they.
It looks like you could stop a train with one though.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
Take a look the later part of the following link:
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Sometimes I only open my mouth to swap feet...
RE: Mechanical delay.
Some soft-starters will just save the present lockout time values when they are turned off and return to the same lockout time when powered back on. Other soft-starter have a built-in time clock and they can re-calculate what the lockout time should be when powered on. I guess there could be one out there that has a supercap and just keeps timing that I don't know of too.
I think AB has a true electronic one - try 700-HRQ maybe.
RE: Mechanical delay.
The problem you will find with the lower cost pneumatic timer attachments for control relays mentioned by ScottyUK is that they don't usually have a clear time value on the dial adjustment like those Agastats do. They have a range printed on the front and a tapered indicator on the screwdriver adjustment dial, but getting an accurate setting is a trial and error procedure as waross mentioned earlier. You may want to consider it anyway if price is an issue. After all, you are probably only going to set it once.
RE: Mechanical delay.
RE: Mechanical delay.
These same units also have a nasty requirement of a minimum ON period for the delay period to be valid. No doubt this is the time required to actually charge the energy storage device/s. Typical is about 1 second some need 2 seconds.
The ole Agastat needs 50ms for hours of delay! This means a guy poking a "start" button will supply the necessary 'charge time'.
I do like the Agastat's nice setting and superb data sheet.
Advantage: Fast and accurate so I can test and debug with a 10s cycle then confidently set the 15 minute period.
Disadvantage: Idiots can easily devine the function and crank the knob. When the motor or SS fries they can also quickly re-adjust it before whining about 'a problem'.
I would use the Agastat, and to hell with the $$, if you guys can assuage my fears or suggest a solution with respect to the Disadvantage.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
They used to have a "tamper-proof" cover option that might at least slow down the evil-doers a little.
I believe they also have a little NEMA 1 enclosure that hides the whole thing.
RE: Mechanical delay.
http://www.hi-line.com/chemicals-torqueseal/203
I've also used lipstick in a pinch, but it's a little easier to clean off and replace (although hopefully Bubba doesn't carry any with him!).
RE: Mechanical delay.
Thanks people.
Happy 4th.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
RE: Mechanical delay.
Interesting company.
Their data sheet is clear.
The price is exactly 1/2 of an Agastat.
The minimum ON time is 7 seconds! Ouch.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
I had my head inside a new 70kv class SF6 breaker today. I thought of you when I saw on the relay rail, a Telemecanique relay with a pneumatic timing head added.
Respectfully
RE: Mechanical delay.
RE: Mechanical delay.
That's also why they continue to survive as a product when most of their competitors have fallen away; that and the fact that the contacts on the Agastat are rated for 600VAC, where most other timers are rated 250VAC/DC max. It allows the Agastats to be used in full voltage circuits such as large contactor coils or even small motor operated valves.
PS: For those who are curious as to why I know so much about Agastats (aside from being a user years ago), my ex-employer was in the hunt for buying that division of AMF when they were being divested, and I was assigned to evaluate the viability of that product in the marketplace. We lost out to the big bucks at Tyco.
RE: Mechanical delay.
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Sometimes I only open my mouth to swap feet...
RE: Mechanical delay.
I have used line voltage on coils when there are very large contactors involved where the coil inrush would require a huge transformer to supply it. An interposing relay to a lower control voltage works wonders for that, and if there needs to be a timer involved, I have used the Agastats as that interposing device because its contacts were rated for it. I would never consider running a line voltage control circuit anywhere outside of a control panel though, in fact, not even off of the back pan!
RE: Mechanical delay.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
We would love to know how the final design turns out.
Yours
Bill
RE: Mechanical delay.
I'll show you soon.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
LOL
Bill
RE: Mechanical delay.
Obscure reference to "White Punks on Dope" by The Tubes eh?
RE: Mechanical delay.
What do you want from life
To kidnap an heiress
or threaten her with a knife
What do you want from life
To get cable TV
and watch it every night
There you sit
a lump in your chair
Where do you sleep
and what do you wear
when you're sleeping
What do you want from life
An Indian guru
to show you the inner light
What do you want from life
a meaningless love affair
with a girl that you met tonight
How can you tell when you're doin' alright
Does your bank account swell
While you're dreaming at night
How do know when you're really in love
Do violins play when you're touching the one
That you're loving
What do you want from life
Someone to love
and somebody that you can trust
What do you want from life
To try and be happy
while you do the nasty things
you must
Well, you can't have that, but if you're an American citizen you are entitled to:
a heated kidney shaped pool,
a microwave oven--don't watch the food cook,
a Dyna-Gym--I'll personally demonstrate it in the privacy of your own home,
a kingsize Titanic unsinkable Molly Brown waterbed with polybendum,
a foolproof plan and an airtight alibi,
real simulated Indian jewelry,
a Gucci shoetree,
a year's supply of antibiotics,
a personally autographed picture of Randy Mantooth
and Bob Dylan's new unlisted phone number,
a beautifully restored 3rd Reich swizzle stick,
Rosemary's baby,
a dream date in kneepads with Paul Williams,
a new Matador,
a new mastadon,
a Maverick,
a Mustang,
a Montego,
a Merc Montclair,
a Mark IV,
a meteor,
a Mercedes,
an MG,
or a Malibu,
a Mort Moriarty,
a Maserati,
a Mac truck,
a Mazda,
a new Monza,
or a moped,
a Winnebago--Hell, a herd of Winnebago's we're giving 'em away,
or how about a McCulloch chainsaw,
a Las Vegas wedding,
a Mexican divorce,
a solid gold Kama Sutra coffee pot,
or a baby's arm holding an apple?
http://www.youtube.com/watch?v=00lccIIBA6s
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
jraef....
I and an able associate spent much of yesterday trying to devise the required functionality with any reasonably available Agastat. We followed your,(broken - LOL), sentence about 20 times and come up with a similar but not desired functional result.
Here's the 7000 series Agastat data sheet.
htt
Let me reiterate hopefully, more clearly, the desired functionality.
Also the topology may not be exactly what was imagined.
The OUTPUT signal is the signal from a smart relay wanting to turn on and keep on the pump - not a push button directly controlling the pump. I need to protect the pump/SS from an insane "smart" relay.
Remember: The timer period is 15 minutes and must carry thru any power failure.
An OUTPUT, (from the smart relay), goes TRUE.
A timer starts AND an ENABLE signal to the SS goes TRUE.
The ENABLE signal stays TRUE until the OUTPUT goes FALSE.
IF the OUTPUT goes FALSE then TRUE before the timer times out. Then the ENABLE will never occur.
If the OUTPUT goes FALSE then TRUE anytime after the timer times out then the timer restarts AND the ENABLE occurs.
All I can muster from the Agastats is a time delay after the OUTPUT goes FALSE. This means the time period starts after the last time the machine is turned off. Which would mean an operator who runs the machine for 3 hours turns it off for a cancer-stick break returns 10 minutes later and can't start the machine for another 5 minutes. Not good.
(This would make sense if I was soft stopping the motor and needed to allow the SS to cool but I'm not.)
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
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Sometimes I only open my mouth to swap feet...
RE: Mechanical delay.
I wasn't thinking of the "3 hours run time" scenario, so my more simplistic circuit will always have the restart delay as you have observed. "Not good" I take to mean not good eh?
OK, got one more unused output from the smart relay left? If so, I'll draft up the circuit and post it for ya. If not, back to the drawing board
RE: Mechanical delay.
Use the 15 minute timer initiate when the full run condition is obtained. Use a 2p PB and relay if necessary to get this (instantaneous, non-maintained) signal. A N/C contact on the TOF will have permitted the start actuator (PB) to initiate the startup. After 15 min it will again permit start actuation. Yes, (X) minutes after any start actuation another will be permitted. Energizing the TOF after the "DRIVE START" signal has initiated the startup can be obtained as aux contacts/outputs from some "drives", or can produced by a CR or ordinary TDR.
I'd ladder this for you, but without familiarity with the actual SoftStart and fluid based TDR (TOF) chosen it'd be useless or worse yet, misleading.
Fluid based is not a necessity though. I've used TDRs with memory-like functions, whether battery, super cap, or whatever you'd like to call them. As far as that goes even lawn sprinkler timers are memory retentive these days.
...or am I entirely missing something here???
Please let us all know how this works out for you! and don't forget FAQ731-376: Eng-Tips.com Forum Policies
RE: Mechanical delay.
You got me thinking along the lines of; make the Smart Relay do it.
I decided since I've blown my engineering budget on just this "simple" little SS/motor protection scheme, I'm going to allow the Smart Relay to "be" the protection.
Again, the problem is being able to carry thru during a power loss,(most likely intentional), the No-Restart-before-15-minutes-has-passed since the last restart.
Turns out the Smart Relay timers are all lost on PL but certain counter values are retained indefinitely.
I figure I can use this feature to achieve my mission,(already stated above), with only a small anomaly. I can count minute or second pulses constantly generated by a timer using a nonvolatile counter. The only caveat is if you turn off the power during this period the count stops and will pick up where it left off. So in a fifteen minute count if the yahoo turns off the power 10 minutes into the count and comes back three days later and turns it back on he will still have to pay the piper those last 5 minutes. At any rate this provides the 15 minute protection to the SS/motor which is the bottom line.
To wit; I have created this logic. It appears to actually work!! I'd like any creative criticism you guys might have.
I labeled most the non obvious stuff. Letters match the coils. Lower case seems to mean N.C. for some reason.
Oh and the "D" is a pulse, one Smart Relay cycle scan output pulse.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
Commissioned the Press today.
Couple of shots of the controller, and of the Press itself.
My controller is working great. There are a few details with the hydraulics that others will be fine tuning. None as bad as the hose that was missing so 1,100PSI hydraulic oil shot out the back hitting the wall twenty feet up. LOL
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
Sorry to be getting in late. Do you think that this would have worked?
1 A start signal pulls in the Agastat relay.
2 An instantaneous contact on the Agastat energizes a small relay that seals itself in and energizes the motor contactor.
3 An auxiliary contact on the starter de-energizes the Agastat.
4 The Agastat will now time for 15 minutes. A set of normally closed, timed contacts will now be open and are used to prevent a start signal from reaching the Agastat coil until 15 minutes has elapsed, regardless of whether there is power or not.
The small relay is for the purpose of avoiding circuit race. With some combinations of timers and contactors it may be dispensed with.
I hope that this is understandable.
Respectfully
RE: Mechanical delay.
That sounds like it would work!
I licked it with the above Smart Relay logic and its ability to remember a count thru power cycling. The Smart Relay was needed for other functions anyway.
It's in and running. (See above.)
Thanks.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
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I don't have an attitude problem. You have a perception problem...
RE: Mechanical delay.
I hate that big disconnect! Just sitting there with death written all over it. Very annoying.
I was able to get a cover for the buss splitter but then it's nearly touchable without a cover due to its depth.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
I comes from the ubiquitous influence of the Automotive industry on our standards and practices. They want everything easy to get at and test, no barriers or other "impedances" to getting the production line back up and running quickly. That is rapidly changing here though. They have begun stricter implementation of what we call Arc Flash Safety protocols which are now incorporated into our National Electric Code. Some of the things Kieth did might cause someone trouble later on if and when an inspector comes along and insists on an Arc Flash safety rating for that panel. As it is now, looks like a level 3, maybe 4. That would mean the full bunny suit if you open the box!
Keith,
I guess I'm going to have to come over and give you an education on Arc Flash safety construction considerations with regards to control panels. Just another excuse to have my boss pay for lunch eh?
RE: Mechanical delay.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
Regarding arc energy: I'm no expert but I'm currently trying to raise awareness of the risks of arcing faults at our site. I thought the ratings were based on available fault level and protection characteristics rather than the amount of bare copper? Or are there a different set of regs I'm totally ignorant of? We're trying to apply the intent of the NFPA 70E standard on our British equipment and it is proving interesting. There is a lot of resistance to wearing the Category 3 and 4 suits because of the discomfort levels. A few have remarked that any task which is dangerous enough to require us to wear a 'space suit' should not be done live.
Sorry for dragging this OT!
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I don't have an attitude problem. You have a perception problem...
RE: Mechanical delay.
Those big fuses are current limiting and this panel is served by a 100A breaker. Seems like a substantial amount of limiting.
Hey Jeff, how about a napkin arc-flash calculation on this thing.
What info does one need to start with?
Or is it a royal pain in the butt-don't want to do it task?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Mechanical delay.
Some folks like myself have to troubleshoot and service (even occasionally modify or re-wire) equipment like this, and many of us HATE much imported equipment with IEC type components and practices, because accesibility is a consideration.
Yeah, that disconnect and the fuseblocks are really a bit much,,,, but it's no more dangerous than euro-stuff - always too tightly packed in - with the covers removed for troubleshooting, and test probes nearly touching each other and other devices because of those tight clearances.
RE: Mechanical delay.
Bad design is just bad design, wherever it is built. I send designs like that back to the designer covered in red pen and rude phrases! I have to live with the stuff we design - I'm on call one week in six - so I have a take-no-prisoners attitude with designers who use crappy components loaded right up to their rating and who squeeze things in too tight.
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I don't have an attitude problem. You have a perception problem...