I am trying to fix an old three-phase drill.
The motor has 3 wires coming out of it, which connect to the three phases.
Connecting it to the power does nothing, and so I tested it with a multimeter, and saw that two of the wires coming from the motor are shorted together, but not with a good connection (~25ohm).
I am not educated on electricity beyond your common layman knowledge, and definitely not on why three phases are needed or how they are used (or indeed, what this term even means, beside the obvious 3 wires)
Therefore, my assumption at first was that this short is a fault somewhere inside the motor.
Then upon reconsidering, I realized that if the three phases are completely separate, and there is no 0/ground going to the motor, then how can the circuit be closed?
Is this short indeed a fault? how is there a closed circuit when the only lines going into the motor are power lines?
Given the useful answers and comments, I can only assume something inside the motor is bad. This is because 1) Nothing at all happened when it was connected to electricity, not even anything bad. 2) The multimeter shows there is only a physical connection between one of the three pairs. I will hopefully be able to test this further and supply photos tomorrow. Thanks!
/After further testing
It seems I was misled, and the three phase socket in the wall didn't even have any power running to it. Whoops!
With actual power feeding into the motor, it sort-of tries to spin, with A LOT of resistance, and eventually after a few seconds manages to spin very slow. It gets very hot.
Because there is only a physical connection between one of the three pairs, I am guessing this means that only one of the phases actually does any work.
I'll try perhaps to fully open it, although I don't believe I have quite the right tools for the job.
Thank you a lot for the answers and explanations, at least I have some basic information about this subject that I knew completely nothing about two days ago :)
The motor was sent to be fixed, and indeed the windings got ruined and had to be remade.
A big thank you to you all on educating me :)