Centrifugal pump issue

[Anthony5]

This morning when I went into the pump house I noticed that the breaker for the irrigation pump had tripped.

 

I closed it again and tried to start the pump, but all I got was a buzzing sound. The pump is a 2Hp Mitsubishi Super pump.

 

I moved it outside, dismounted the front of the pump, and tried it again but it blew the fuse from the extension cord within a second.

 

When I connected it to the power outlet without an extension cord it ran fine.

 

So mounted it together again, installed in the pumphouse, and it ran fine upon first test.

 

I then filled it up with water, and got the buzzing sound again.

 

In the connection box at the side of the pump are two tin  bombs installed , I assume that are capacitors. Is that correct?

 

Would that also be my issue why the pump runs dry, but doesn't start up when full of water, that one of thos capacitors has died?

 

How do I test them?

[Crossy]

Yes the beer cans are the capacitors,  and I suspect you are right one or both has died.

 

They're not expensive, replace them both.

 

If you take them out you should find the value marked, take to your local pump chap for replacements.

[Lamkyong]

i agree the capacitor idea  sounds   likely     before attempting this make sure both are fully discharged ie bridge the terminals to delete stored power

 

 

 

 

make sure you replace with the exact values as probably printed on the caps  don't know your skill level but a couple of photos may help with  reassembly

[Anthony5]

I'll just go to the shop and ask them to check them out. Thanks for the contributions, I like to be informed about the most possible cause, saves me from being ripped off.

[Anthony5]

6 hours ago, Crossy said:

Yes the beer cans are the capacitors,  and I suspect you are right one or both has died.

 

They're not expensive, replace them both.

 

If you take them out you should find the value marked, take to your local pump chap for replacements.

 

What do you consider inexpensive Crossy?

 

They charged me 500 Baht a piece. I guess I've been had, yes?

[Crossy]

What value are they?

 

I would have said about 300 a pop, but it's a pretty big pump, you're probably not a zillion miles off, did they fit them too?

[Anthony5]

44 minutes ago, Crossy said:

What value are they?

 

I would have said about 300 a pop, but it's a pretty big pump, you're probably not a zillion miles off, did they fit them too?

 

They are 30 -  450V, and yeah they fit them but I brought the pump to them disassembled already, so took them all but 10 minutes.

 

They first wanted me to believe that the problem was not with the capacitors, but when I insisted that they tested them they had to agree.

 

Anyway, the pump now works again, but I still notice that when I activate the pump through the irrigation control unit, the lcd screen from the control unit goes blank for a second.

 

Is that normal, because I have a contactor installed that operates the pump?

 

 

[Crossy]

Did it go blank before?

 

It's probably volt drop caused by the pump starting, if everything is working ok I wouldn't worry.

 

BTW, they're about a fiver on Ebay, probable Farang price

 

[Anthony5]

Just now, Crossy said:

Did it go blank before?

 

It's probably volt drop caused by the pump starting, if everything is working ok I wouldn't worry.

 

 

 

 

Yes I noticed a few days ago it went blank, and was kinda worried at that time, as I don't know it has always been like this. So I was thinking that the reason it went blank at was because at that point one of the capacitors had died already, so it pulled too much power to start but could still get over it, and now the second had given up.

 

Both were indeed dead