Submersible pump testing

[Jako13!]

My question is how can you carry out an IR test on a sealed pump connected in star. My guess is you can only test phases to earth. Is this the case?

Thanks

 

[telectrix]

and you'll need to use a IP68 MFT if it's a submersible pump. .

 

[westward10]

My question is how can you carry out an IR test on a sealed pump connected in star. My guess is you can only test phases to earth. Is this the case?

Thanks

Yes, what reason do you need to do it because as a routine IR test this would be what is required.

 

[PEG]

Hi bud,we would need to know the voltage,too...

 

[David Prosser]

You have pretty much answered your own question. Why do you think it there could be more to it ?

 

[LeeH]

You can also test for balanced resistance on the windings.

The last one I tested was star delta started so that was possible to measure each individually obviously.

 

[Deuce]

I work in water display automation and often call in sparks to test kit ahead of going on display. It's amazing how many look for additional ways to test submersible pumps. It's as if you guys can't accept a simple days work

It's double insulated, the end. Test IR. That's all you need to do and all I expect. If it holds up, pass - if not, bin.

On some seriously top end (££££) multistage submersibles you might get involved in deeper testing to see if it's worth breaking into the pump and refurbishing it. But in general, the insulation showing signs of failure alone will result in the pump being condemned and a new one put into service.

I understand you might want to be really 'on it' when dealing with electrical kit that lives in water. But rest assured, water is at best a shockingly bad conductor in real terms. Most of the failures we identify in house are not initially discovered at the time of electrical testing, but when we enter a pool and feel an odd tingling sensation, especially noticeable if you have any broken skin. Might sound a little flippant, but consider that millions of children have their arms in fish tanks with submersible filter pumps that are never tested. Of course, many do fail and many moons ago I worked in the ornamental aquatics trade - a tingle up the arm as people serviced their fish tanks was often the deciding factor in spending £30 on a new pump/heater, whatever had failed.

If you want to feel warm inside that you have done all you can, don't just test. Open up the plug/panel and physically check and re-torque the earth at each terminal back to the main circuit. That way, no matter what fails on the pump, the current has a place to go that is easier than water>victim.

 

[Wilko]

Hi Deuce - do you happen to know what the posthumous IR results were for a pump replaced due to tingles? Also, for your displays do you use circuits with 30mA RCD or go for something more sensitive? Just interested .

 

[static zap]

.... Might sound a little flippant, but consider that millions of children have their arms in fish tanks with submersible filter pumps that are never tested......

And my favourite kamikaze fish that crack test tube heaters by sticking to them !
(Caution "Conductivity may vary" --Posh Marine setups )

 

[Deuce]

Hi Deuce - do you happen to know what the posthumous IR results were for a pump replaced due to tingles? Also, for your displays do you use circuits with 30mA RCD or go for something more sensitive? Just interested .

The problem is that once it's failed sufficiently to give a tingle, the water is already causing a near total failure in resistance. Impossible to clear the water that has broken through so results will be highly erratic. In all events though, very unlikely to see more than 10k ohms achieved even after drying out and the internal moisture settling. As a final effort we will cut the cable about a foot from the pump, and test again. If this gives a good result we know it's the cable that has some damage, and can be replaced. However in most cases if the outer sheath of the cable has allowed water to enter, that water will have travelled down the inside of the outer sheath, straight through into the pump internals = both cable and pump will independently fail IR tests.

There is no real way to get a reading on a submersible pump that is close to failure, as it either has already suffered water ingress or it has not.

Yes we just use 30ma RCD. Anything more sensitive no real use with pump motors. Even 30ma is a bit of a pain using motors and solenoids but there is no other option really. We used to use several smaller pumps started in sequence to achieve the same as a single larger pump in order to minimise inrush. And pretty much all new pumps we use these days are 3 phase on soft starters which avoids the issue altogether. We have also switched to using surface mounted pumps wherever possible, more for neatness than safety.

 

[Deuce]

And my favourite kamikaze fish that crack test tube heaters by sticking to them !
(Caution "Conductivity may vary" --Posh Marine setups )

Yup, the salty water is a far better conductor

It's crazy when you think about those heaters. A body of water generally less than a bathtub. A cracked aquarium heater, internal terminals fully submersed, and then you top up the salt and stick your arms in. Result = probably won't even notice.

And a room containing an aquarium isn't zoned. Makes you wonder how this has escaped regulation!

 

[Wilko]

The problem is that once it's failed sufficiently to give a tingle, the water is already causing a near total failure in resistance. Impossible to clear the water that has broken through so results will be highly erratic. In all events though, very unlikely to see more than 10k ohms achieved even after drying out and the internal moisture settling.

Perfect, thanks for sharing

 

[David Prosser]

What pumps do you use for these displays. Any links to the displays as apart from the Bellagio don't think I've ever seen a decent water display.

 

[Deuce]

Perfect, thanks for sharing

I get so much useful input about general electrical regulation and method from this forum (i'm not a spark). It's nice to be able to occasionally give something back in the form of my rather niche industry experience

 

[Deuce]

What pumps do you use for these displays. Any links to the displays as apart from the Bellagio don't think I've ever seen a decent water display.

Varies greatly! Mostly main circulation pumps are now surface mounted 1-3hp variable speed units, typically controlled by their own integral timer/panel. For the FX water jets we use Calpeda on-demand pressure pump sets. They're great as they maintain extremely even water pressure regardless there being one, or twenty display nozzles being activated at the time and releasing water.

The submersibles for FX are generally DMX controlled 3 phase units. Relatively low power, the 3ph is used purely to enable accurate control of pump speed.

We don't really do public large scale displays like bellagio (which I have visited twice). Our kit is generally used for water FX such as rain/mist for product press launches, TV/Film and also walk through displays/events.

Here are a few random bits:

Immersive rain FX:

This guy... :

'Shark' Tank:

BGT:

More League:

It's all just larking around really