Hardinge HLV motor and speed control question

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31 Mar 2020 11:59 #162241 by jools
Yes there is a low speed and high speed switch on the headstock casing. I think it's 500 and 1500 rpm.

From my investigations and everyones helpful answers I'm narrowing down to two choices.

Swap for 240v three phase with VFD
Swap out for AC servo

As a side question what kind of torque levels do these type/size of lathe need to work properly? From searching it seems that this motor doesn't have much torque at all.

Cheers all

Jools

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31 Mar 2020 12:50 #162252 by andypugh

Yes there is a low speed and high speed switch on the headstock casing. I think it's 500 and 1500 rpm.

You could probably set up a 750rpm motor and a VFD so that the same switch runs it at 500 or 1500. (ie under-drive a bit or run at double speed)

As a side question what kind of torque levels do these type/size of lathe need to work properly?


Lathe powers have gone up a lot. If you look at machines from the 60s 1 to 1.5 hp was normal.
Modern CNC lathes can have 50 to 100hp spindle motors. Even manual lathes have 3+ hp (quick Google says the current COlchester Master has a 7.5kW spindle motor)

An AC servo would be a lot more effort and expense to drive, and is a more expensive thing.

If you want to control speed with CNC for CSS etc then it might make sense to swap out the current drivetrain for a 3hp motor and VFD.
If you do that I would go for a slower-speed motor and over-drive it for the max spindle speed to get a bit more torque in the typical operation range.
You might want to also consider changing the belt ratios. Do you know what the output speed range of your variable speed unit is?

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31 Mar 2020 13:36 - 31 Mar 2020 13:46 #162261 by jools

You might want to also consider changing the belt ratios. Do you know what the output speed range of your variable speed unit is?


up to 3000 on the high power level and think it's 60 - 250 on lower level.

With the motor's RPM and HP on high range I make it that it has seven -sh NM of torque.
Could I use a Ebay servo which has 4NM at 2500 RPM. If I geared it down 2:1 then that's 8NM @ the spindle at 1250 RPM (unless torque drops off with speed on these servos) (Something that I've been trying to find on google also but come up blanks for a servo speed torque graph).

Main thing I'm turning is Delrin, max diameter 170mm. I'm not too bothered about removal rates being major as this is being used to produce high value low quantity parts.

Cheers

Jools

Edit. Reason looking at servo's is I can find them on Ebay easily. Searching for 3 phase 220v induction motors seems to bring up every type of motor but :-)

Edit 2: Actually I'm being a moron. I have one of those servo's driving my mill's spindle. I should try that and stop wasting your time until that's been tested :(
Last edit: 31 Mar 2020 13:46 by jools. Reason: Adding edit

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31 Mar 2020 16:47 - 31 Mar 2020 16:47 #162275 by andypugh

Edit. Reason looking at servo's is I can find them on Ebay easily. Searching for 3 phase 220v induction motors seems to bring up every type of motor but :-)


Maybe try (three phase. 3 phase, 3-P): motor 3HP

Though you could just go to a shop:
inverterdrive.com/group/Motors-AC/?filte...ype%7cInverter+Rated
Is where I would go. Which country are you in?
Last edit: 31 Mar 2020 16:47 by andypugh.

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03 Apr 2020 15:27 #162587 by jools
I'm uk. Those look good. Can't for the life of me think why google didn't chuck them up in the numerous searches I did.

Thanks for the link.

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03 Apr 2020 17:52 #162599 by andypugh
4-pole versions seem rated at 7+ Nm and intermittent use at 2880 rpm. I think I would go for those rather than the 2P ones.
inverterdrive.com/group/Motors-AC/TECA2-...cy-3HP-4-Pole-Motor/

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