Late to the party a little - but here goes.
If it "sometimes doesn't start without a spin" and "sometimes spins backwards" then it sounds as if you are missing not 1 phase but 2. If it were single phasing, then the motor would only run in 1 direction - the correct direction. The lost phases could be either at the supply end or the starter.
The only possible way that the motor could run in either direction would be if it were running as a single phase machine. The start direction would be dependant on which direction you spin it before starting it.
Overheating also supports this theory, as does the contactor not holding in. However, there could be another reason.
The "Azul" wire (blue) on the schematic right side looks to me to be a derived neutral from the star point that should connect to the neutral of the start contactor. In 400v mode, there is a derived neutral (230v across the winding), in 230v mode the motor would be delta so it gets 230v direct from the winding connection. Hence the reason the coolant pump (230v) is connected there also. If your buddy has connected the cooling pump at the starter across 2 phases then probably that has been fried by the 400v - although it is conceivable that it picks up the blue in the starter coil.
Recommendations - Get a qualified Electrician who actually knows what they are doing first of all. Based on the first picture, absolutely
not the person who connected it. It is a deathtrap as it sits.
Lack of earthing, non-glanded cables, terminal box cover unable to be properly fastened due to hard wired cable.
Nice that they used crimps, but the crimps do not look to be propetly crimped either. Does it even have overload protection? It should, as it's 6.25 amps in star. Have they used the blue core as earth? Even if you do get it working, unless the cable is properly glanded and sealed, then pretty quickly your going to have a short in the motor due to water and damp stone dust.
My guess is that cable from the starter to the motor got damaged and replaced? If there was a short circuit it could have damaged the starter contactor.
Then get them to try below:
- Isolate and take a winding balance across the windings to verify all are good. Reading should be low ohms, all within 10%.
- Insulation test the motor - disconnect the star point if you need to test each winding individually.
- Verify that the contactor contacts make correctly when the contactor is pressed in. Should be almost zero ohms across each line.
- Verify that you have 3 phase 400v at the starter.
- If all the previous suggestions are good, connect the blue core to the star point, restore power and test run it.
Finally - whoever wired this thing up, made a shocking job of it. It is worthy of the hall of shame, and I really would not use them again for anything even remotely electrical. As it stands now, it is not safe to run.
