Keep replacing 2008 Mazak QTN450-2 Spindle cooling fan motor

We had a Spindle cooling fan overtemp alarm back last spring, Maintenance replaced it and all was well until this week when it did it again, The operator opened up the end of the machine and put a floor fan blowing on the Spindle cooling fan and continued running.... It seems to be when we are making heavier cuts that this happens.

Now the alarm is the Spindle cooling fan itself not the spindle, there is a thermal switch in the Spindle cooling fan motor that is tied to a input. We have plenty of air flow to cool the spindle.... everything seems normal no other high temps.... just the little Spindle cooling fan

Myself and the maintenance manager think that something weird must be going on... There is no way we should have to replace the Spindle cooling fan again...


Has anybody else had this issue? I am thinking a power quality issue (internally to the machine) or a magnetic field from the spindle affecting the Spindle cooling fan.

Mazak said last year that they have not seen many of these Spindle cooling fan go bad...

thanks

This does seem odd...
Not familiar with this machine, but first thing..Is the motor a 3phase? Have you checked to see that the legs are even under load as to voltage and current?

I think the problem is internal to the machine electrics too. Out of habit, I always check all the connectors back to the source, then start with the voltages.

Something else to look at is to make sure the motor is in fact what's spec'd for that machine and not accidentally underrated, and there's no surprise flow restrictions.

....and the ubiquitous sensor itself....

Fizzissist,

thanks for your reply,

My continued research has found that this is a single phase PSC type motor on this cooling blower.

And now the capacitor is suspect, if it is bad, it can cause the symptoms that we are experiencing.

I just am surprised that this problem comes and goes, usually when the cap goes bad it stays bad....

oh well, we will replace with a new one and see what happens, we may replace the motor as well as it could be stressed and could cause a repeat problem.

We are seeing the same issue with a Mazak 450-2 M We are getting intermittent 360 Spindle Cooling Malfunction alarms. Mazak has told us to check two memory locations to see if bit E is a 1 or a 0. Address XOE being a 1 would indicate that the oil pressure is high and the spindle cooling oil strainer may be clogged? Address X97 being a 1 would indicate that the thermal switch in the fan itself is throwing the error. Every time I have checked both locations have been 0. According to Mazak these are the only two things that can cause the error. I did remove the fan itself and clean all the fins in the squirrel cage type fan. I then checked it with an amp meter while running and the fan is pulling about 1 amp. Which is well within the .8 to 1.8amp ratting of the motor. On the other hand I can not find a spindle cooling oil strainer anywhere in the machine. No place in the maint manual does it describe such a piece of equipment. And honestly I can not see where the two areas coincide. Neither appears to be tripping the error and yet we are still getting it....Does anyone know if replacing that capacitor worked? I see no further entries here?