Hubbard Scroller Condensor Fan Problem

[Northdude]

I have been working on 2 joint multideck display cabinets with 2 remote hubbard scroller condensors (1 condensor doing 1 deck), one of the condensors has been plagued with problems and the latest being the condensor fan motor (single phase), been called out to it twice in 3 weeks with same problem, find unit tripped on HP switch, reset and find condensor fan not turning so unit trips out again so reset again and fan starts spinning and works ok. Both condensing units are identical BUT the condensor fans are wired differently, the fan comes with 4 wires, black,brown,blue and earth, On the good unit (with no problems) this is how it is wired, blue - 240v power in, black - capacitor and brown - capacitor, which seems correct but on the other unit, blue - 240v power in, black goes to a terminal with nothing in, brown - capacitor and other wire on capacitor goes to Neutral . I have tried wiring this fan the same way as the other unit but it wont run at all. I had this problem with the same motor 6 month ago so i replaced the motor and capacitor and wired it the same way the old one was and its worked ok up to a few weeks ago, just cannot understand why it wont run when it appears to be wired correctly using all the wires and why it runs most times and recently it wont start up, if anyone can shed any light on this will be much appreciated, thanks :rolleyes:

[lowcool]

has the motor got a thermal overload etc

[Northdude]

Not that i am aware of, when the motor fails it has power to it but it seems like its a starting problem related to the way the capacitor is wired in? But 9 times out of 10 it works ok

[lowcool]

put wiring back to original,will it run in either direction if you give it a flick,is the capacitor open circuit,have you compared it to the makers wiring diagram.being a capacitor start run motor it more than likely has a short across windings this will produce a low torque and probably not get to speed

[Northdude]

Going back on saturday so will wire it the same way as the other unit and try flicking it to get it going, the motor and the capacitor are only 3 month old as thats when it first happened so i replaced them both, u think its a problem with the motor? There are no manufacturers wiring diagrams on any of the units.

[littleyapper]

is there fan speed control on one of the fans....
i dont know but it might be holding that fan out ...