X Axis Servo Motor Overheat

[mtgpaul]

Just wonderin if anyone else has ever had this problem as well. We have 2 Tornado A90's and one of them for the last 3 months has been giving us a 430: X Axis: SV Motor Overheat alarm, we have done everything imaginable to eliminate this problem from replacing the encoder, and the motor itself to removing the entire turret and replacing the lead screw and the bearings on the X axis. Also had a Fanuc guy slow down the controller to lower the amp draw of the motor, even though the amperage draw when the alarm comes up is within operating range. Replacing the lead screw and bearings allowed the machine to run for 3 or 4 weeks untill the other day when it suddenly came up again leaving us scratching our heads at what the problem is. The colchester service guy or the Fanuc guy didn't know what the problem is. Just wondering if anyone has come across this, and if they have, if they found a solution.

[gridley51]

Have you checked out the slide/screw lubrication system?
Checked the gib is not floating/broken?
Take it this is a flat bed so there won`t be an axis brake.
Is it an OT control?
Mark.

[squiz81]

In short, I had an A90, and had no end of trouble with it. In the first 2 months of having it, the seals in the turret burst emptying the hydraulic oil into the coolant. The explaination was that "the machine mistakenly had pneumatic seals installed in the factory". Then, we replaced the drawtube actuator 4 times in 3 years as they would split internally, or leak copious amounts of oil and spray it all over the drive belt and pneumatics.
"X-axis servo overvoltage" problem occurred and it turned out to be the x axis VSD dying. It was intermittent problem that slowly became more and more frequent. We were quoted $14k plus instalation for a new VSD - that meant that there was no longer room for it in the shop. The machine was not worked hard. 5 days a week - maybe 6hrs per day. Then 10 - 12 weeks downtime each time we had to replace the actuator. The machine was bought brand new.
Subsequently got rid of it and have never looked back at a Taiwanese alternative that now runs 16hrs a day 6 days a week without missing a beat.

[HuFlungDung]

FWIW, I used to see a similar spurious error on my Haas. Turned out to be a weak/dying power supply that supplies some power to control circuits on the servo drives (not the main motor power).

In retrospect the error was always ascribed to the first active drive in the 4 drives that were daisy chained. So if I was running 3 axis, I think the Z axis had the overheat alarm, but if I happened to be running the 4th axis, then the A axis had the overheat alarm. It was not overheat at all, just the way that control interpreted a loss of power on that drive.

[fanuc fix al]

paul,
you could see if the x servo is actualy getting hot, if it is swap the motor and drive onto another machine, if its getting hot it could be:-

overloading/ overloaded,misfiring drive, brake intermittantly being de energised, motor encoder misaligned to motor rotor.

if the motor is hot and you need to get production get an airline and rig it to blow on the servo constantly. BTW squiz is right tornado's are not the best machines i had one with a cracked chucking cylinder piston a few yrs back

[cncdiag]

I would check the encoder cable for a possible brake to the motor overheat sensor.
Try flexing the cable to see if you can cause the alarm