# lift station help



## wildleg (Apr 12, 2009)

sounds like a nice homework question.


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## Jlarson (Jun 28, 2009)

wildleg said:


> sounds like a nice homework question.


Yeah. No one does alternating pumps in the real world without an alternator, preferably one with a selector switch too. And who ever wrote this problem needs to learn what red and green lights mean in the real world. 

Draw it how you think it should be done then post pictures.


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## JRaef (Mar 23, 2009)

wildleg said:


> sounds like a nice homework question.





Jlarson said:


> Yeah. No one does alternating pumps in the real world without an alternator, preferably one with a selector switch too.


Yep, I agree, homework. Nobody does this in the real world, it's a ridiculous concept to implement in light of the fact that Alternating Relays exist and are far cheaper to implement.

That said, it can be done, I did it for years when I worked for a company that insisted that we build duplex and triplex pump panels with our own components, and we did not have Alternating Relays. Here's the hint to get you going in the right direction: think Latching Relay and Early-Make/Late-Break aux contacts on an interposing relay. See if you can figure it out that way (assuming you know what that means). Again, ridiculously over complicated compared to just using an Alt. Relay, but technically possible.



> And who ever wrote this problem needs to learn what red and green lights mean in the real world. ...


Uh-oh, hunker down for the annual "Stop Light" vs NFPA 79/ANSI Pilot Light Color Scheme Flame War! Time to get out the asbestos underwear... :gunsmilie:

Volley 2: 
Red on PILOT LIGHTS means Hazardous condition, Running, Energized, Not Safe. Green on PILOT LIGHTS means Normal, Safe, Stopped.

Red on PUSH BUTTONS means Stop, Return to Normal, Green on PUSH BUTTONS means Start, Run, Energize.

But that is not what everyone believes...


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## Jlarson (Jun 28, 2009)

Flamewar!! Yay.


I figured that might get you. Here if you use a red pilot light for running you are likely to get it ripped out of the panel and chucked at you :laughing: Even on things that fall under 79 it seems to be regarded as dumb here.


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## Peewee0413 (Oct 18, 2012)

Rhetorical question....how do u alternate motors without alternating run command via relay/s.....hmmmmm maybe you don't.....I know they exist but how much do they cost? I have seen micrologix to alternate motors. The relay must be cheaper.


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## Tom45acp (Sep 6, 2011)

Use a PLC, it does not have an alternating relay, but you can write the program so that it acts as if it does.


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## erics37 (May 7, 2009)

Tom45acp said:


> Use a PLC, it does not have an alternating relay, but you can write the program so that it acts as if it does.


:laughing: That's what I was gonna say.


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## Jlarson (Jun 28, 2009)

Peewee0413 said:


> I know they exist but how much do they cost?


Like 60 bucks.


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## ScooterMcGavin (Jan 24, 2011)

I must not work in the real world then, because we have this exact setup all over the place using nothing more than a Westinghouse AR relay with standard contacts to control the alternating portion of a two pump scheme. Granted it takes a little bit of extra wiring, but I don't think thats its anything too outrageous. 

While I am at it. One more vote for Red = running/open


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## Wirenuting (Sep 12, 2010)

A good alternating relay isn't cheap, but they last for years.


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## Big John (May 23, 2010)

Had to wire a motor starter recently where they wanted the "traffic light" scheme for control lights. I'm used to seeing everything done to NFPA79. It just felt... _wrong_. 

Red means "Stop, idiot! Don't stick your damn hand in there!" 
Green means "Yeah, go ahead, you big dummy."


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## sparkywannabee (Jan 29, 2013)

Red means "Stop, idiot! Don't stick your damn hand in there!" 
Green means "Yeah, go ahead, you big dummy."[/QUOTE]

In the printing industry, push the safe button in, steady green light comes on and press is safe to work on, push the ready button, safe button disengages and red light, flashing or solid, comes on, means press is ready to inch over, no sticky hands in.


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## Jlarson (Jun 28, 2009)

I don't want to ever operate any water plant or pump station any of you ever built. :no: We'll be there forever just changing the pilot lights out so they are all right.


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## erics37 (May 7, 2009)

Jlarson said:


> I don't want to ever operate any water plant or pump station any of you ever built. :no: We'll be there forever just changing the pilot lights out so they are all right.


F**k that, I just don't use 'em.


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## Big John (May 23, 2010)

:laughing:


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## dronai (Apr 11, 2011)

Tom45acp said:


> Use a PLC, it does not have an alternating relay, but you can write the program so that it acts as if it does.





erics37 said:


> :laughing: That's what I was gonna say.


Flip Flop logic yes ?


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## Peewee0413 (Oct 18, 2012)

Flip flop banana pancakes yes....


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## Peewee0413 (Oct 18, 2012)

But a PLC costs more than a relay. Plus your normal wannabe tech is unable to even program it.


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## dronai (Apr 11, 2011)

Peewee0413 said:


> But a PLC costs more than a relay. Plus your normal wannabe tech is unable to even program it.


 
$60 for the relay vs $120. for an automation direct. Can you program ?


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## Peewee0413 (Oct 18, 2012)

Nope so im a wannabe ....but you hand me a pile of relays and timers, i'll give you any logic u want....lol


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## dronai (Apr 11, 2011)

I took a training, and that flip flop was a bitch !


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## dronai (Apr 11, 2011)




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## sseivard (Apr 25, 2012)

Not sure how to paste it but there is a logic function called a "drum that can be used for pump alternation.


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