How measure 3 phase motor for faults

[Pogust]

I had to to buy a new deep well pump. 1 hp with capacitor sitting in pump house. Worked for a short time before giving up. It draws 6 amps measured at 220 connection in. When measure after capacitor the 3 phases going to pump I get 2,8 3,8 and 5,8 amps. 10, 23, 18 ohm measured across the phases with pump disconnected.

Pump at 70 m down, going to take it up again tonight.

 

Any suggestions how to check pump?

[Crossy]

Before hauling the beast up 70m, try testing the capacitor by substitution, it's by far the most likely failure point.

 

Are you getting those currents in each wire but the pump isn't actually running??

 

I'm assuming you have a single-phase, capacitor-run (3-wires + ground) rather than an actual 3-phase pump.

 

 If the pump is actually new then it's time to go back to the supplier if it's not the capacitor.

 

 

[Pogust]

 

10 minutes ago, Crossy said:

Before hauling the beast up 70m, try testing the capacitor by substitution, it's by far the most likely failure point.

Thanks Crossy. Yes I have changed a number of capacitors before, they don't seem to like the heat here.

I changed to one I got for spare now, didn't work either.

 

10 minutes ago, Crossy said:

Are you getting those currents in each wire but the pump isn't actually running??

Yes.

12 minutes ago, Crossy said:

I'm assuming you have a single-phase, capacitor-run (3-wires + ground) rather than an actual 3-phase pump.

Yes. Is there any difference in the pump between them?

 

Cooling down now so will take up pump.

[Crossy]

A pukka 3-phase pump will have very different windings to a single-phase capacitor pump, what you are measuring resistance wise suggests you do have the right kind of motor (it wouldn't be the first time although an actual 3-phase motor likely wouldn't have run at all).

 

Anyway, since you seem to be drawing something like stall current, I wonder if the rotor is locked (sucked in a rock?) or is it even actually seized.

 

 

 

[Pogust]

OK thanks then I understand. I have used industrial 3 phase motors that  I fitted with capacitor myself in another life. Problem was the start torque, when running it worked fine.

 

Problem solved anyway! Halfway down I found a glueing broken on the cheap blue pipes the well driller used 4 years ago. It broke when I got pressure in the system. I would use hdpe instead, but can't find the proper metal fittings here. Only plastic fittings and I have bad experience with them. Would to import from Europe.

[carlyai]

You can buy the thicker walled plastic pipe here.