Whats causing a voltage increase on a water pump?

[Delectrician]

Hello.

I'm doing a favour for a farm friend, they have a water pump down a bore hole thats been slowing down recently.
The single phase 0.55KW motor is situated 40m down the well and the controls are at the distribution boards.
The voltage going to the single phase motor is reading L-E 247 & L-N 314.
The farmers wired it all himself with all red coloured singles and has a hand made drawing of his overload and starter controls.
What could be causing the increased voltage ?

 

[James]

Floating neutral,
Fault probably lies with a cable or distribution board upstream of the pump and control box

 

[Lucien Nunes]

If his supply is single-phase the problem is 99.9% with the DNO. If his supply is 3-phase or split-phase the problem could be anywhere upstrem of a 3-phase or split-phase DB. Other stuff could be getting fried so needs isolating and sorting. If the pump is getting 314V but running slow, it's probably already wrecked.