Spindle at 30% when running 400rpms

[carbidecraters]

Does anyone else have this issue? When these were new they ran with one bar showing and it seems like a couple of our mills are showing 30% spindle load without doing any cutting. The spindle rotates easily by hand so I almost think the gauges are bad.

[tomfitzgerald]

Got a brand new PUMA 400 Lathe with the same thing. Sits on 18% at a dead stop.

[Konstrukter1]

My Fadal also got 30% when doing nothing
I do not think, that that is a problem. Its yust meaning that the measuring device is relativ to friction(on 10 000 rpm with 1mm ballnose tool, is 5%).

[Shizzlemah]

Similar issue here.
Low speed spindle operation is HIGH load on the meter.

Increasing RPM will decrease load. With my 2speed spindle, 100RPM is like 100% load, and 2500 RPM is near 5%.

I have always assumed this was due to the original analog load meter and a replacement spindle drive not cooperating. Or, the analog load meter from a -2 system with a -5 brain.

The meter is pretty inaccurate for a baseline load, but can show a relative shift. Not nearly as useful as it could be.

[carbidecraters]

I wonder if a new meter is in order. Even our digital meter is showing 2 bars when the machine is running on another 3016. Is it possible the spindle motors could be wearing out?

[Shizzlemah]

Not sure if it is the display or what, $350 for a new display isn't all that tempting when I don't know if it is the problem or not.

I should also add that the motor is not that heavily loaded. My new spindle drive has a handy-dandy display showing V,A,Hz. It's not running hard at all, just the oppositie of the load meter's reading.

[carbidecraters]

Originally Posted by Shizzlemah Not sure if it is the display or what, $350 for a new display isn't all that tempting when I don't know if it is the problem or not. I should also add that the motor is not that heavily loaded. My new spindle drive has a handy-dandy display showing V,A,Hz. It's not running hard at all, just the oppositie of the load meter's reading.

We are probly dealing with faulty worn out analog meters

[alconatech]

if the machine hs an older spindal inverter AMC the meter would show a load when the drive was starting to fail

[Big_d]

If it was my machine I would confirm the load via a tong test meter. There could be a problem with drive belts??.

[carbidecraters]

Originally Posted by Big_d If it was my machine I would confirm the load via a tong test meter. There could be a problem with drive belts??.

On a Posi unit the belts crunch and wont effect load. The spindle turn easily with the motor and at higher RPM's the load goes down. Its a very strange situation and I wouldnt rule out anything yet...even belts.

[Shizzlemah]

On my machine, belts are nearly new, maybe 100 hrs cut time on them.

If I get some downtime this weekend, I'll run a little test and report spindle load meter reading versus spindle drive readings for I/V/Hz.

Then, um, maybe I'll have to call Neal :-)

[Edster]

I had a bad analog meter. It would sit around 30% all the time unless I tapped on it, then it would show a better reading. I replaced it with the digital meter. I think the analog was around $300 and the digital was around $75.00. It was a no brainer. I still have the old one if anyone want's it.