Inspecting a flooded electric turbine pump - video transcript
Pat Daley from Daley Water Services describes how to inspect a flooded electric turbine pump in a case study video.
[Pat Daley from Daley Water Services]
Today we're looking at a submerged electric turbine pump and you can see there by the debris how high the water has got.
Some of the areas we will look at with the pump will be: the switch gear or control gear, the motor itself, and the pump discharge, also the borehole assembly.
This is a hollow shaft electric motor and most hollow shaft electric motors are important to have air through them to cool them.
The shaft goes up from the pump through the centre of that motor and we've got a vent here and a vent at the top so it is important to, one, make sure that there is no debris closing those off, but in the case where it has been completely submerged, it is a good idea to remove the hollow shaft motor and have it looked at by an electrician. The electrical people will pull the motor apart and dry out all the bearings and wiring.
The procedure to pull the motor off is that at the top there under the hood, there's an adjustment nut with a locking screw. It is important to note where that locking nut is, and where the locking screw is, when you need to reassemble the unit. So it is just a matter of undoing that nut, and the shaft will drop down slightly and you use the lifting lugs on the motor to lift that motor off the shaft.
To lift the motor you need something that has a straight pull. A loader is very cumbersome to do something like that because as it lifts higher, it pulls in closer to the tractor which could bend the shaft.
The areas that need to be looked at are the things like the discharge head. You can see that there is a lot of build-up of stuff around this discharge head that would need to be removed. Anything like this that builds up around the packing gland – the packing gland is the piece that seals the water from coming out and pushing up into the electric motor, and also stops things from going down inside. If you have got sediment built up around the packing gland inside there you could wear the shaft out.
I can see looking in here that there is some deposits of sediment there - if you were to run this pump before you cleared that it would grind away on that shaft.
The other areas that would also be looked at is to make sure that there is no, if there is any air gaps around between this discharge head and the bore cap you could get sediment that goes down inside the bore. So it is important to check that hasn't happened. Fortunately with this pump nothing – it's all sealed with a rubber...some insertion rubber.
The other areas that you might look at are things like the pre-lube tank (which has floated away in this case) but this hose here is normally connected to a small tank that puts water down inside the pump to lubricate the rubber bushes. It is important to make sure there is no sediment in there because that sediment will wash straight to the bearings.
We move onto the electric components – obviously if these have been under water like this one, all this needs to be looked at by an electrician. It doesn't mean that it automatically can't be used or that it has got to be replaced. Quite often it just needs to be thoroughly dried out. But an electrician needs to check them out.
And once again remove some of this debris.
The other thing that can happen even if the control mechanism doesn't go under water it is a good idea to thoroughly check because you get all sorts of critters, ants, frogs, what have you that want to get up to higher ground and live in these boxes. It is amazing with a small opening what size animal can get inside.
All the glands and the cabling on the control boxes need to be looked at to make sure there has been no logs, or things like that, which could have pulled these out, and make sure they are tight. The electrician would normally pull those cables apart because quite often you will have water that would sit inside these conduits and that needs to be drained out.
When we move onto the discharge of the pump there are things like this air valve here that we can see there are deposits of sediment, grass and things in the valve there. That all needs to be pulled apart and cleaned out for it to function correctly.
The other areas is the flow meter. The flow meter should be relatively safe from submergence. However, some of the electronic readers are not submergible – they're only drip proof.
- Last reviewed: 21 Sep 2022
- Last updated: 21 Sep 2022