electrical control panels for water pumps

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C240Sport97

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I live in a building with 85 apartments in East London.

Our water system has 3 high capacity pumps (each pump is 7.5KW) providing water pressure to the entire building.

The 3 pumps are controlled by an electrical panel. 1 pump has sufficent power to provide water pressure to all 85 apartments.

There are 3 pumps for resilience and back up purposes.

The current electrical panel is supposed to rotate the use of the pumps as well as control the output of the pump in service using an 'inverter'.

Current electrical panel has a fault -- the 'inverter' is no longer working, nor is the rotation of pumps in service. This means that 1 pump is now on all the time at full power.

Contractors (WILO and City Pumps) have suggested:

1. all new pumps and control panel for £18,000 plus VAT;
2. keep existing pumps and install new control panel, repair 1 of the pumps for £12000 plus VAT -- new control panel costing £10,500 plus VAT; or
3. repair existing control panel (new inverter and associated bits) for £2000 plus VAT, and repair 1 of pumps as no.2.

New control panel will have 3 'inverters', and will be able to use all 3 pumps in low power mode to manage water pressure better, and to save electricity (apparently).

Apparrently, new pumps are not as well made as the current ones (which are about 15 years old).

Am no engineer, but the old pumps sound fine to me.

Am inclined to go for option 3.

I am staggered by the cost of the inverters and control panels.

Any thoughts, suggestions or comments (such as alternative suppliers) would be most welcomed.
 
I would go for option 3 and see if further work is needed later on, unless it can be demonstrated that the pumps need attention.
 
Option 3 for me too, I spec panels and pumps for mining applications and this duty you have is tiny. You just need one duty and one standby pump ideally pumps need to run between 50% - 75% for efficiency but depends what the pump curve looks like when supplying all 85 supply points at full, worst case scenario but this is what you spec on.

2 x 7.5 Kw clean water pumps, panel, inverters, alternating software all new I reckon £12k - £15k for a complete new installation

Option 3 should last for years if done properly though
 
... Apparrently, new pumps are not as well made as the current ones (which are about 15 years old) ...
It's actually the 3 phase motors on modern centrifugal pumps that are inferior. Up until about 3 or so years ago the 3 phase motors had a certain degree of over engineering with respect the copper windings meaning that a motor could run on a variety of voltages and more importantly could run on either 50 or 60 hz. The design also meant that motors were relatively robust. These days, in the name of quoting high efficiency figures the manufacturers have cut back on the copper in the windings making modern motors much less flexible and less robust. More significantly, if a modern motor is specced for 50hz then it can only run at 50hz and not 60hz, etc.

I would also go for option 3... 3 phase motors on clean duty water pumps are usually bullet proof and go on for years without issue. It sounds like the motor control circuits in the control panel are the items requiring attention / replacement. As flanaia has mentioned, 7.5kW would be considered tiny to small in terms of a typical water pump.

BTW, I'm a Chemical Engineer by training, working for an industrial water treatment company, one of my main areas of expertise is automation and control but I also get involved in pump design as well as specifying design and build of control panels.

The following website might be of interest.
Inverter Drive Supermarket - Variable Speed Drives for Electric Motor Speed Control
You didn't mention the make of the inverter drive but they might be listed on that site. May be of help to negotiate a better price.

S.
 
BTW, I'm a Chemical Engineer by training, working for an industrial water treatment company, one of my main areas of expertise is automation and control but I also get involved in pump design as well as specifying design and build of control panels.

S.

^ Spot on :thumb:

Snap that's my field too, although most of my time at the moment is mining process chemicals for solid/liquid separation and tailings management. I did Oilfield for several years specing various drilling and fracking fluids etc and a little bit of drinking water and sewage treatment.
 
^ Spot on :thumb:

Snap that's my field too, although most of my time at the moment is mining process chemicals for solid/liquid separation and tailings management. I did Oilfield for several years specing various drilling and fracking fluids etc and a little bit of drinking water and sewage treatment.
:cool: :rock:
Let me guess... Acid mine drainage treatment that's massively loaded in iron and other metals? I've worked mainly in industrial water treatment with a little involvement in municipal, e.g. waste water / drinking water. Have done a few trials for acid mine drainage applications or tailings pond treatment. Our core business is electro-coagulation / flocculation equipment followed by traditional separation by either gravity settlement or flotation, replacing traditional chemical dosing systems.

Nice to see a like minded soul :) :thumb:

:fail Apologies for dragging this thread off topic!

S.
 
:cool: :rock:
Let me guess... Acid mine drainage treatment that's massively loaded in iron and other metals? I've worked mainly in industrial water treatment with a little involvement in municipal, e.g. waste water / drinking water. Have done a few trials for acid mine drainage applications or tailings pond treatment. Our core business is electro-coagulation / flocculation equipment followed by traditional separation by either gravity settlement or flotation, replacing traditional chemical dosing systems.

Nice to see a like minded soul :) :thumb:

:fail Apologies for dragging this thread off topic!

S.

Just filed some patents on AMD and a novel new treatment that hopefully will be a game changer.

You are not the guys that did the AMD job in Jo'burg a few years back are you? they were from Wales as I remember.

Sorry to derail the thread yet again :doh:
 
Just filed some patents on AMD and a novel new treatment that hopefully will be a game changer.

You are not the guys that did the AMD job in Jo'burg a few years back are you? they were from Wales as I remember.

Sorry to derail the thread yet again :doh:
:eek: Err... Yes. That was 2011, I was one of the 3 guys out in Jo'burg doing the trials.

Bloody hell, small world!! :eek: :crazy:

S.
 
:eek: Err... Yes. That was 2011, I was one of the 3 guys out in Jo'burg doing the trials.

Bloody hell, small world!! :eek: :crazy:

S.

I don't think I met any of you guys but I was dealing with the South African company on a little bit of flocculation work at the same time and they kept on telling me there would be no need for chemicals in the future.

IIRC were they not going to ship the unit around various sites and test it and then build locally if all went to plan? I hope it did all go well for you guys a lot of people have had their fingers burned in RSA

Small world indeed :thumb: but agreed nice to meet a like minded person :thumb:
 
What's the warranty on any repair/replacement? Old pump repair seems a good idea- I'm not sure on the control circuitry. All those components/boards subject to heat and vibration ageing capacitors etc etc Sounds as if new control circuitry might not be bad idea and possibly prolong the life of the old pumps. Also depends on how the cost is to be borne------ split between 85 flats its around £150 each?? Might also be worth getting some alternative quotes?
 
Work is still on-going, know what you're saying about working relations out in RSA though... but, yes, that's us.

Heh, talk about a 'Global Village'. Well it's good to make your acquaintance... Lol, next time I'm stuck for an idea I know who to msg! ;) :thumb:

Heh nice one!! This thread will now resume its normal course.

S.
 
What's the warranty on any repair/replacement? Old pump repair seems a good idea- I'm not sure on the control circuitry. All those components/boards subject to heat and vibration ageing capacitors etc etc Sounds as if new control circuitry might not be bad idea and possibly prolong the life of the old pumps. Also depends on how the cost is to be borne------ split between 85 flats its around £150 each?? Might also be worth getting some alternative quotes?
Typically, the components within the panel e.g. MCB's / Contactors / Relays/ Switches / Inverters etc. will have a 12 month warranty. The components will be designed for the type of environment that will be subject to those heat and vibration stresses that you mention. The control panel will probably have forced cooling in the form of a ventilation fan and filter. My guess is that the company quoting for the work might also want to quote for a maintenance service contract too to look after the kit once it has been installed and commissioned. Depends on the nature of their company. i.e. whether they are more process orientated or just out and out 'panel bashers'.

S.
 
What's the warranty on any repair/replacement? Old pump repair seems a good idea- I'm not sure on the control circuitry. All those components/boards subject to heat and vibration ageing capacitors etc etc Sounds as if new control circuitry might not be bad idea and possibly prolong the life of the old pumps. Also depends on how the cost is to be borne------ split between 85 flats its around £150 each?? Might also be worth getting some alternative quotes?

2 year warranty on replacement control panel

control panel is completely separate from the pumps, see pics below

cost is spread out between the 85 flats .. our annual running cost is approx £400,000 (we have 6 permanent staff).


Typically, the components within the panel e.g. MCB's / Contactors / Relays/ Switches / Inverters etc. will have a 12 month warranty. The components will be designed for the type of environment that will be subject to those heat and vibration stresses that you mention. The control panel will probably have forced cooling in the form of a ventilation fan and filter. My guess is that the company quoting for the work might also want to quote for a maintenance service contract too to look after the kit once it has been installed and commissioned. Depends on the nature of their company. i.e. whether they are more process orientated or just out and out 'panel bashers'.

S.

one company wants to sell pumps and won't even quote to repair the control panel, it is pushing option 1 and is the current maintainer.

other company is suggesting option 2, but is happy to deal with option 3 too. They have quoted for maintenance too, and are about 15% cheaper.

I like the second company better. First one is too big and too annonymous.

Thanks for all your input. I'll go for option 3.

the pump repair is a contingency ... it's not certain that the pump is damaged.


DSC_1202_zps8f047a29.jpg


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DSC_1205_zps65e4764e.jpg


DSC_1206_zps41f518c2.jpg
 
Ooh piccies! :thumb: :D

From my perspective that looks like run of the mill equipment...

- ABB ACS 600 Variable Speed Drive
- Standard centrifugal pumps, never dealt with Pillinger before but they look good enough. I normally play with Lowara or Grundfos which are very similar to yours.

Looking at the display it looks like the thermistor (thermal trip) circuit keeps activating which is in tune with your original post if I re-read this thread.

S.
 
Ooh piccies! :thumb: :D

From my perspective that looks like run of the mill equipment...

- ABB ACS 600 Variable Speed Drive
- Standard centrifugal pumps, never dealt with Pillinger before but they look good enough. I normally play with Lowara or Grundfos which are very similar to yours.

Looking at the display it looks like the thermistor (thermal trip) circuit keeps activating which is in tune with your original post if I re-read this thread.

S.

pics don't change your mind about option 3?
 
I'm with Steve too, pretty much of the shelf equipment, Pillinger I believe are a panel basher pump builder seen them on Thames water sites, so suspect pump manufacturer is different but again totally agree Lowara or Grundfoss, I normally spec Grundfoss because of fantastic after sales service.

Option 3 still looks good to me :thumb:
 
Great thread, very interesting.

I don't deal with water pumps, but do with other electro-mechanical devices and I agree with the thoughts so far. The motor has thermal protection which has tripped, so should be undamaged.

As before, due to the control panel only running one pump, unless it can be demonstrated that the motor has a windings fault which has damaged the driver due to over-current, just repair the control circuit, at the most a new driver and motor repair should guarantee a long term fix.
 
C240Sport97,

I'm not sure whether you will want to monitor and / or check progress of the trouble-shooting process when the engineers come to do the re-fit work but there are easy ways to check to see if one of the suspected pumps is 'goosed' or not.

1.) Run each of the pumps individually for a few minutes and have a good listen. They should be relatively quiet during operation and completely free from vibration. You're lucky that you have 3x off identical pumps so they should all run and sound exactly the same, that will make identifying a 'duff' pump all the more simple as you should have two good ones to compare against if you know what I mean.

2.) If you think you have identified a knackered pump out of the three then you can take things one step further...
2a.) If it's obvious that the issue is mechanical i.e. heavy vibration or loud squealing from the wet-end then a strip down will identify the culprit, usually debris lodged in the impeller head or sometimes a failed mechanical seal.
2b.) If you think the issue could still be electrically related then you can disconnect the pump from the variable speed inverter drive and connect it directly to the 3 phase electrical supply via the protective MCB and controlling contactor and run the pump again, this will eliminate the drive from the equation and allow you to test the motor on a pure 3 phase feed. This way of running a pump is known as DOL or Direct On Line, that is the motor will always run at 100% when connected directly to a 3 phase electrical supply. If the pump motor runs smooth on DOL but rough from the inverter then that would indicate a faulty inverter drive issue (The ABB ACS600 that I mentioned earlier). If the pump motor runs rough on both DOL and from the inverter then that would indicate a failing motor, most probably bearings or possibly the windings.

Please, please, please, these trouble shooting ideas that I have written down should ONLY be performed by qualified personel who know what they are doing!! I'm just giving you these ideas so that you are more informed and be in a better position to judge those people doing the work for you. The advice above is NOT written down as an incentive to go DIY!!! I make that very clear!

You can see that, like a car mechanic, being an engineer is sometimes like being a detective and following the clues presented to you. Faults can be identified and corrected with some logical problem solving skills.

@Dieselman, I'm not a car mechanic but I can tell you that I am my dealership's and / or my car mechanic's worst nightmare! ;) :devil: :D

S.
 
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