Roof exhaust fans

[Lex]

Hey guys, I could do with some help.
I'm out doing a job and the site im working on has two buildings, both have a roof mounted exhaust fan for the toilets. Either is working. I've checked and they both have a supply. I have a little experience with motors but not enough for this kind of fault finding. each has 6 pins, the top two are linked, the bottom left hand pins are link as are the bottom right hand set. between the middle two there is 240v, between the bottom 2 there is 240v. between the top left hand pin and bottom left hand set is 287v, between the top right hand pin and bottom right hand set is 187v. as shown below (roughly)

Dont know if you can actually see that
any advice on how to get them running would be greatly appreciated

 

[chronyx]

Are the ones with odd voltages related to speed control?

 

[ayjay]

are the capacitors knackered? they have a capacitor for start-up its fitted on the body of the motor
try replacing one , its difficult to test a capacitor btw
as chronyx mentioned , a speed control is often fitted somewhere in the circuit, usually above a false ceiling

 

[Lex]

I've decided to replace the capacitors. they dont have a dead short but its my best guess atm. I dont think they have speed control, but to be honest I dont know. cheers for your advice ayjay

 

[ayjay]

its worth a try lex ive had a few that have developed open circuit or a short to earth
they fit speed controlers to slow the fan a bit probably to reduce noise from the ducting
the speed controller can clap out as they get pretty hot, especiall in a ceiling void also some fans run 24-7