Pumps running confirmation

[guest119]

Hi team,
Control panel for 2 submersible pumps, duty, assist.

Need to come up with something to confirm pumps running, not just signal to do so.
Was thinking ct on the outgoing connections but I would need a pair of voltage free contacts from this to create a confirmation signal.
Is there a Siemens or similar module known to do this?

Thanks,

Boydy

 

[44ALLAN]

Use a N/O auxiliary contact on your main contactors to feed a couple of indication lights?
Simple but effective.

 

[Darkwood]

This wont confirm the pumps are running only that the contactor, or power out is present, you need a fail safe indicator with possible alarm and using a flow sensor is the best bet here as any issue with motor, supply, water etc will come up as an alarm, it dosn't rely on the fact if the motor is powered then its working which isn;t always the case.

 

[guest119]

Thanks Al but that only confirms the command and contactor closure.
I need to know pumps are running, drawing current.
For example if a downstream isolator was off, no current drawn.

Boydy

 

[Darkwood]

We are limited to set up knowledge here but so many options exist, current monitoring relays, ameters with CT clamps you can purely use them for indication or intergrate them for fuctional control if conditions are not met, would have to know exactly what the customer needs and the consequences of pump failure to know best route... some times you need to tell customer the best way not just agree to his request, if motor impellor broke the current would still show albiet lower value but oil/water flow would be lost and no-one the wiser until possible machine damage etc occurs ....

It might seem overboard but a risk assessment is needed when adapting controls as to why your fitting them, what happens in various circumstances and would damage occur or down time be costly.

 

[ian.settle1]

Why don't you fit an ammeter for each pump so when they are running you can see what current they are pulling.

 

[guest119]

Thanks DW,

What is needed is a remote signal to confirm non run after command received.
Pump impeller or thermister etc faults would go out on alarm anyway and then the non run (higher priority) signal would go out next time a command was given and not responded to.

Thanks,

Boydy

 

[44ALLAN]

Thanks Al but that only confirms the command and contactor closure.
I need to know pumps are running, drawing current.
For example if a downstream isolator was off, no current drawn.

Boydy

Very true and agree with you and Darkwood.

Its a method we employ on Haz. area panels for a hydraulic pump unit...............indication lights for the operator e.g motor run/motor/stopped/tripped/lamp test etc.
Panels are normally mounted next to the motor so the noise lets him know it's actually running lol.

Totally different if the motor is remote from the panel though like you both have stated.

 

[guest119]

Getting there

AS1 Series Current Sensing Switch | NK Technologies - San Jose, CA 95136

Boydy

 

[scooby61173]

Boydy,
What about using a flow meter with a 4-20ma output (or similar) that you can connect to an analog input on your control circuit, then you will have an indication if you have a blockage etc ?

Regards,

Dave

 

[Deleted member 26818]

Another option might be for a pressure sensor on the output side of the pump, or two sensors, one either side of the pump?

 

[stef]

Easiest option would be a three phase current monitor, no plumbing involved, no cables to run. RS is selling them, but not cheap.

 

[Knobhead]

Simple always works.

Use a pressure switch in series with a N/O contact on the contactor.

It will confirm the pump is actually pumping something.

 

[mydigitalhome]

Flow meter as previously suggested would be the way I would go. Best of luck.

 

[Deleted member 26818]

The only problem I can see with a flow mwter, is that the business end may restrict the flow.

 

[Darkwood]

You can get adjustable ones spin and they have the added bonus of ensuring waterflow so if any restrictions occur its seen, differential pressure switches also can be adjustable but that cant always tell a blocked flow as the pressure can still remain high.

A faulty valve or blockage wont be seen by most sensors as the motor will keep going and just cavitate (in some cases this reduces current demand of motor believe it or not as the cyclonic water assists the motor)...

 

[grantr37]

Hi team,
Control panel for 2 submersible pumps, duty, assist.

Need to come up with something to confirm pumps running, not just signal to do so.
Was thinking ct on the outgoing connections but I would need a pair of voltage free contacts from this to create a confirmation signal.
Is there a Siemens or similar module known to do this?

Thanks,

Boydy

Hello, what are the pumps being used for? I ask this as every usage has a different possible solution/improvement that can be applied to it......will help me to work out what you might want to find out about....


grantr37

 

[guest119]

Sorry, been drip feeding info, should have started with the big picture.

Factory sewage wet well.
2 pumps (duty-to a certain level. assist-at higher level) submersible Flyght pumps.
Float switch operating at overflow pipe spill level currently sending its own alarm.
Pumps send the ---- on to the street sewer.
No access to pumps or valves, no mechanical solution.


Problem.

Float sending too many alarms.
No alarm required in bad weather when the spill will be mostly clean/rain water and the pumps are just not keeping up but will eventually.
Alarm required when float operates and pumps wont obey ultrasonic run command, ie mains fail or both switched off downstream or both ragged up and tripped their overloads.
Analogue wont work in mains fail.

Available alarms

Well high.
Well spill (float)
Pump running/stopped
Pump available/not available (stop selected,or not)
Pump tripped/not tripped
Mains fail


Thanks for current support,

Boydy

 

[Darkwood]

This poor setup requires a re-draft of the control system and possible redesign its flawed in many ways by the sound of it as it dosn't really operate correctly in all conditions hence they are just adding sensors to try give more indication if its working and although it might give a little more info its not going to address the operational issues and its something i couldn't do on a forum ... even with the info supplied

Good luck

 

[guest119]

Just to add instead of edit of above.
A spill generates a hefty fine therefor need the float to call out only on a ---- spill, not a dilluted spill.

Boydy

 

[Darkwood]

Well sounds like this needs a complete new control system to address the problems rather than adding extra indicators and no offense meant but because of the opening question you asked i would assume its out of your field of experience ...by all means add the indicators as asked but dont get any deeper because you may become liable on any alterations that dont work as expected and with fines been handed out you want to avoid any blame.