Bridgeport 2hp motor max speed with vfd?

I have a teco L510 3 hp 230 v vfd running a Bridgeport 2 hp mill motor

Motor and mill are getting new timken bearings and I'm converting to a fixed speed polyv drive.

The mill is a boss 3 axis cnc running centroid acorn

I plan on using it for prototyping and general light milling so (1000 to 3000)rpm in high gear

But it would be nice to have more rpm available for small cutters or wood working ie 6000+rpm

So how fast i can spin the motor will determine the drive ratio

Motor tag

I was going to ask you for the tag when I first did the read here. Then an hour later ...

I wouldn't go above 1710 rpm. Sure you're going to get a few replies that say you can go higher. Not worth it for the small speed increase. Is 1800 rpm going to get you much further along?

Sorry about the late photo my internet is very limited up here and even worse in my shop.

I'm surprised with the 1800 rpm
This mill had a old ge vfd when I bought it that was set to 120hz and it ran ok (the bp belt drive was noisy)

So I'm leaning more towards overdriveing the spindle less and running more hz to the motor to get the top end.

The question is how much hz can I throw at this motor.
I understand that the torque will fall off as I go up but I only plan on running small tool up high ie .25

And I'm not raceing anyone to the bottom I just want a usable machine

I would ditch the stock motor....it's likely worth $500 by itself!
You can buy new surplus Baldor motors that are rated for 6000 rpm for a reasonable price?

Kevin

Hbjj said:

Sorry about the late photo my internet is very limited up here and even worse in my shop.

I'm surprised with the 1800 rpm
This mill had a old ge vfd when I bought it that was set to 120hz and it ran ok (the bp belt drive was noisy)

So I'm leaning more towards overdriveing the spindle less and running more hz to the motor to get the top end.

The question is how much hz can I throw at this motor.
I understand that the torque will fall off as I go up but I only plan on running small tool up high ie .25

And I'm not raceing anyone to the bottom I just want a usable machine

Click to expand...

Run it at twice the frequency (120Hz) with 25% torque. Not advisable.
Twice as fast and twice the wear. And for what. If you can't do something at 3000rpm then ...

rons said:

Run it at twice the frequency (120Hz) with 25% torque. Not advisable.
Twice as fast and twice the wear. And for what. If you can't do something at 3000rpm then ...

Click to expand...

I would be far more worried about the spindle bearings and associated lubrication capability at the higher speeds. Typically motor safe speed is at least 50% above rated speed.

I oversped my motor a lot on my Bridgeport but only because I converted it from a multistep pulley to a single pulley. In order to make up for the lost torque I went from the original 1 hp to a 3 hp motor. I ever exceeded original spindle design rpm.

The bearings I'm replacing are rated for around 10k rpm and the spindle is run over 4k by many people
I think as far as bearing loading goes and bp spindle is really light duty

This mill has the motor on the underside of the belt housing because of the ballscrew they add so there is limited room for a different motor there I could put it on the top like a regular bp but man it would be up there!
Anyway I do like the idea of a different motor

I don't have your motor... I have the 1hp 'pancake' motor on my J-head, using stock step-pulleys, but I basically leave it in direct-drive (1:1 position). I have my VFD set to 170rpm, and the pancake starts to get wierd around 160... I had to do some small-diameter work, and so I ran the pulley in overdrive with the motor at about 165hz. Nothing special about my spindle, it's clean and well-oiled, and it didn't seem to care. High-speed rated spindles are partially about bearing specs, but I think moreso about maintaining rated deflection under G-forces as the bearings and spindle tube warm up.

My other J-head is in my radial drill, it's a 2.5hp or so, 184T form factor, with the mechanical fan nix'd, and I run that motor in excess of 6k, but with a 3:1 reduction using a toothed-belt. It's a drill, so it spends most of it's timecard at slower speeds.