PLL Pump Lead Lag

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Sparky9876

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I am working on a magnetic motor starter that is controlling some pumps. We are monitoring flow of water from a PLL Lead lag control module picutred below. When there is no water flow the control module has a relay built into it and sends 120 volts to the pump motor starter. In the picture below it has the P1 output labeled L & N. If we send that to the motor starter auxiliary contacts and land them wouldn’t that create a short?
 

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Sparky9876 said:
I am working on a magnetic motor starter that is controlling some pumps. We are monitoring flow of water from a PLL Lead lag control module picutred below. When there is no water flow the control module has a relay built into it and sends 120 volts to the pump motor starter. In the picture below it has the P1 output labeled L & N. If we send that to the motor starter auxiliary contacts and land them wouldn’t that create a short?
Click to expand...

It would. My question is why would you do such a thing?
 
You would not run those contacts to the aux contacts of a motor starter, you would connect them to the COIL of the motor starter.
 
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the relay outputs P1 P2 and P3 are pilot duty, which means they are only designed to drive a small load (identified in print above the terminal block).

further, it does not appear the controller provides you with 120 volts on the outputs. its misleading to label the terminals L and N. they appear to be a form A dry contact. this means you need to place this contact in series with the motor starter coil:

hot |-----o_|_o--------] [-----------(M)-----| neutral
.................ON-OFF...........P1..................COIL
 
Looks to me like the unit puts out 120 volts between the two terminals of each of the P and V outputs, and is a dry contact between alarm terminals.
 
I don't like that this device provides power on those pump outputs. Any pump motor starter that I would have would already have it's own source of power and I don't want them mixing. The more I look at this device the less I like it.

Depending on what the pumps are doing, multiple float switches and an alternating relay would be far more robust IMHO. In some cases, I want to be required to intervene and find out reason for pump failure.
 
Sparky9876 said:
I am working on a magnetic motor starter that is controlling some pumps. We are monitoring flow of water from a PLL Lead lag control module picutred below. When there is no water flow the control module has a relay built into it and sends 120 volts to the pump motor starter. In the picture below it has the P1 output labeled L & N. If we send that to the motor starter auxiliary contacts and land them wouldn’t that create a short?
Click to expand...

You don't land them on the auxiliary contacts, you control the MS coil, making sure you go through the overload switches.

Do you have this? https://www.heat-timer.com/wp-conten...ite-Manual.pdf
 
RTFM baby...
Output Wiring
• The PLL provides 120 VAC 60Hz power to the pump and solenoid valve output
relays. Each relay can power up to 1/4 HP pump (120 VAC 60 Hz) or 80 VA Solenoid
Valves (120 VAC 60Hz).
• The PLL does not provide power to the alarm output relays. A separate power source
must supply the power to the alarm. In this case, the alarm relays act as a power
switches.
Pump Output Wiring
• Before wiring the pumps, decide on the function of each of the pumps based on the
mode selected.
• Each of the PLL pump outputs sources power to operate a pump up to ¼ HP (120
VAC, 60Hz).
• If the pump requires more power than what the PLL can output, use a pump starter or
an external higher output power relay.
• Wire the Pump output terminals to the pumps or pump starters.
Click to expand...

So if you have separate starters, each with it's own separate local source for control power, then use these outputs to energize little 120V relays in the starters that have dry contacts wired are into the starter local control circuit. You will need labels / signs warning people of the fact that there are "foreign sources" of control power in the box, typically run with yellow wire.
 
I suppose it comes down to if you want this device to be your complete control system......or if you want it to only automate what would normally be a manual process of swapping over to a standby pump, a situation that would normally require manually switching a selector switch and opening and/or closing some valves.

It looks like it is sold to be a complete control system. I would need a lot more information to be comfortable with it being so used. I much prefer to design and wire my own control systems, or use a few select vendors that have control schematics I approve of. For example, I don't approve of a flow switch as "proof of flow". Every one I have had experience with ends up with the paddle from the flow switch lodged in the impeller of the pump. For me, there are far better ways to go.

This is a subject near and dear to my heart and I have strong feelings on the matter. A well designed pump control system is virtually self-diagnostic if you know what to look for and quite tolerant of component and/or pump failures.

For example, if this device was your complete control system and you lost your 120 VAC input, would you get any failure alarms? Of course not, and that is totally unacceptable to me in my field of work.

Okay, I'll shut up now, because I could spew a lot more dogma about how a lift station vs a duplex air compressor/vacuum pump vs a boiler feed water system should be wired/controlled. And yes, I'm a dinosaur who wants no part of a PLC controlling my emergency generators.
 
Russs57 said:
I suppose it comes down to if you want this device to be your complete control system......or if you want it to only automate what would normally be a manual process of swapping over to a standby pump, a situation that would normally require manually switching a selector switch and opening and/or closing some valves.

It looks like it is sold to be a complete control system. I would need a lot more information to be comfortable with it being so used. I much prefer to design and wire my own control systems, or use a few select vendors that have control schematics I approve of. For example, I don't approve of a flow switch as "proof of flow". Every one I have had experience with ends up with the paddle from the flow switch lodged in the impeller of the pump. For me, there are far better ways to go.

This is a subject near and dear to my heart and I have strong feelings on the matter. A well designed pump control system is virtually self-diagnostic if you know what to look for and quite tolerant of component and/or pump failures.

For example, if this device was your complete control system and you lost your 120 VAC input, would you get any failure alarms? Of course not, and that is totally unacceptable to me in my field of work.

Okay, I'll shut up now, because I could spew a lot more dogma about how a lift station vs a duplex air compressor/vacuum pump vs a boiler feed water system should be wired/controlled. And yes, I'm a dinosaur who wants no part of a PLC controlling my emergency generators.
Click to expand...

Wow, you must have a really old emergency generator! What happens if the guy that’s supposed to start it within 20 seconds is on break? Ok, his helper and he alternate break times. Good to have redundancy.
 
Russs57 said:
I suppose it comes down to if you want this device to be your complete control system......or if you want it to only automate what would normally be a manual process of swapping over to a standby pump, a situation that would normally require manually switching a selector switch and opening and/or closing some valves.

It looks like it is sold to be a complete control system. I would need a lot more information to be comfortable with it being so used. I much prefer to design and wire my own control systems, or use a few select vendors that have control schematics I approve of. For example, I don't approve of a flow switch as "proof of flow". Every one I have had experience with ends up with the paddle from the flow switch lodged in the impeller of the pump. For me, there are far better ways to go.

This is a subject near and dear to my heart and I have strong feelings on the matter. A well designed pump control system is virtually self-diagnostic if you know what to look for and quite tolerant of component and/or pump failures.

For example, if this device was your complete control system and you lost your 120 VAC input, would you get any failure alarms? Of course not, and that is totally unacceptable to me in my field of work.

Okay, I'll shut up now, because I could spew a lot more dogma about how a lift station vs a duplex air compressor/vacuum pump vs a boiler feed water system should be wired/controlled. And yes, I'm a dinosaur who wants no part of a PLC controlling my emergency generators.
Click to expand...

Russs, we'd likely get along well.
 

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Well StarCat, do you guys brew a good stout or porter? I favor a dry/extra/imperial/american.

Boiler feed water is always interesting because, on one hand, you DON'T want a low water condition in a boiler ever. On the other hand, you want someone physically involved the second it happens. Then we could drink and talk about idiots who disconnected linkage on feed water regulators and replaced secondary low water cut off relays with auto reset relays. I'm always amazed at the levels some folks will go to in order to blow up a boiler and kill people. It takes an extra special level of stupid as some controls aren't so easy to bypass.


Ptonsparky, I'll assume that was tongue and cheek. I'll assure you that the AHJ and NFPA require my generators power the bus at acceptable levels within 10 seconds. For the 30+ years that I had my "old" generators (5 of them) I can honestly say they never failed to do so once in a real emergency. The few times they failed in a full load weekly test run I was able to fix them myself a good percentage of the time. Sadly I can't say the same for my three new 1.5 MW Cats connected to an ASCO based PSG as I'm pretty much dead in the water without the laptop and proper software/training.
 
Russs57 said:
Well StarCat, do you guys brew a good stout or porter? I favor a dry/extra/imperial/american.

Boiler feed water is always interesting because, on one hand, you DON'T want a low water condition in a boiler ever. On the other hand, you want someone physically involved the second it happens. Then we could drink and talk about idiots who disconnected linkage on feed water regulators and replaced secondary low water cut off relays with auto reset relays. I'm always amazed at the levels some folks will go to in order to blow up a boiler and kill people. It takes an extra special level of stupid as some controls aren't so easy to bypass.


Ptonsparky, I'll assume that was tongue and cheek. I'll assure you that the AHJ and NFPA require my generators power the bus at acceptable levels within 10 seconds. For the 30+ years that I had my "old" generators (5 of them) I can honestly say they never failed to do so once in a real emergency. The few times they failed in a full load weekly test run I was able to fix them myself a good percentage of the time. Sadly I can't say the same for my three new 1.5 MW Cats connected to an ASCO based PSG as I'm pretty much dead in the water without the laptop and proper software/training.
Click to expand...

Russ, the Stout is decent. We are undergoing change in ABV%. Its Utah nonsensei, but who knows where it will go. I heard a story about a " Maintenance " boy who put a candle under the pilot burner of a Boiler. One could imagine what other kinds of dangerous charades he was involved in. Of course we have seen the photos in Boiler Books from the insurance company archives. I had a guy on one crew in the recent past who " thought " he could substitute gas controls. Then I worked with an Electrician back at A&M who used to say " A Man has got to know his limits." This is the main problem with Jacks of all trades. They simply do not know or understand limits with respect to Technology, whereas a guy with some simple humbleness and sanity knows when to ask for help and where to find it.10-4 on having an oerator around who knows when not to add water to a boiler and so forth.
 
Sparky9876 said:
I am working on a magnetic motor starter that is controlling some pumps. We are monitoring flow of water from a PLL Lead lag control module picutred below. When there is no water flow the control module has a relay built into it and sends 120 volts to the pump motor starter. In the picture below it has the P1 output labeled L & N. If we send that to the motor starter auxiliary contacts and land them wouldn’t that create a short?
Click to expand...

Those outputs are 120V and should go to your coil or a control relay, not your AUX contacts. As mentioned that unit has a 6A input rating with 2A output rating for each output.
 
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