apac indoor fan motor blowing fuses

[bangoman]

workin on an apac unit indoor model S0321hcsaa,
with three phase belt driven indoor fan motor,rated amps 3.6 running at 2.9 amps .continously blowin fuses two sometimes all three .have meggered motor windin and supply cables all ok .overload set at 4 amps. voltage balanced on all windings .resistance winding balanced all 6.8ohms.

cld I be missing something .\
this happens after some months .

[Brian_UK]

Don't know what area the unit is in but start checking the power wiring.

I recently had a system start blowing fuses when the mechanics all checked out OK.

Found bad wiring inside a switched isolator which had corroded due to moisture. Every now and then the moisture would create an electrical short across the phases and blow the fuses.

[Grizzly]

Brian has a good point there!
You might like to check the incoming voltages as well.
Heavy fluctuations of these would have an influance upon the Amperages being drawn.
If you have the time and option available ?
You could always leave a clamp meter on set to record max amp drawn.
Grizzly
What sort of time scale are we talking about between fuses blowing?

[bangoman]

Grizly ,time scale is once in every 2months we now keep extra fuses on site ,
too bad hey.Hw is the max amp record gonna help me thot they blow because exceed fuse rated amperage.
thanks guys wil implement ur sugestions .