matsuura mc500v mill - VFD advice for spindle motor 80's yaskawa UAASE-5K)

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16 Jul 2023 23:11 #275600 by camb0
Hi,

Will my chinese vevor style VDF safely drive this spindle?
Spindle weighs about 80kg, it's 5kw, nameplate attached, I've worked out the motor specs from the name plate and doco I can find on the old driver and it seems to be:
Max Hz = 137Hz
Max V = 160v
Peak current = 32A
Speed = 120-4000rpm

I've read that the spindle is a squirrel motor design (I'm not 100% confident on that) and that style of motor is very commonly controlled with VFD's with the appropriate considerations for: bearings, spindle grounding and insulation rating of F due to the high voltages (mine is only E rated).

Wiring wise it's got 5 wires, 3 power and an NC thermal switch, bearings seem good and it was running when I picked up the machine.  I can't find a specific manual for the spindle motor, whilst I can find doco that is close in the number but they're nothing like my motor.  So I started looking at the old driver for specs, it's a Yaskawa CPCR-QR90SF-4k, and like the motor I can't find the exact manuals for it but this seems v'close (www.yaskawa.com/delegate/getAttachment?d...ntName=DE6429218.pdf)

The VFD I purchased seems a pretty generic vevor 7.5kw VFD, It doesn't look like I can control the voltage only the frequency.
www.vevor.com.au/variable-frequency-driv...phase-p_010337363762

I've mesg'd Yaskawa for specs and don't have a response as yet and I honestly don't really expect one.

From an electrical engineering PoV I'm pretty sure they will say the motor isn't designed for it so don't do it, which I get but that means I need to buy another motor or use all the old electronics and I'm not keen on either.  In practice others may have had good experiences (or bad) with a similar setup.  I'm tempted to just 'try it' with no load, then increase the load and keep an eye on it but I'm keen to know if any others have experience with this or similar?

Thx in advance,
Cam.
 
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17 Jul 2023 04:28 #275614 by spumco
The insulation class is for temperature, not voltage.  In your case "E" is 120C, and "F" is 155C.

If it were me, I'd run it on that VFD and see if the smoke comes out.

There's probably a parameter to adjust the max voltage for the motor in the VFD.

Minor problem you might run in to is that it has a resolver on it (if my ebay-fu is strong) rather than an encoder.  So you can't just easily hook it up to LCNC for feedback.  A separate belt-driven encoder on the spindle might be an easier option, especially if you're using poly-v belts and not a timing belt.
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17 Jul 2023 04:34 #275615 by spumco
Ignore my comment about a separate encoder - didn't realize it's for a mill.

Shouldn't be miserable to yank the resolver and fit an encoder under the end cover.  I had good luck with a US Digital E6 - they've got a bunch of hub sizes available for different motor shafts.
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17 Jul 2023 05:20 #275619 by besriworld
You can see in the driver's documentation that the maximum current is much lower. One is driving a 3.7 kW motor (200V) with a 7.5 kW Delta driver. It doesn't work well. An alarm is triggered under heavier load. I think you need a much larger driver.
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17 Jul 2023 05:56 #275623 by camb0
You're ebay fu was bang on, I was planning to remove the resolver and put an encoder in it's place, thx for the tip re the US Digital E6.

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17 Jul 2023 05:58 #275624 by camb0
Thx for the advice much appreciated.
Hmm "Delta driver" sounds like my next rabbit hole to read-up and educate myself on.

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17 Jul 2023 13:48 #275646 by spumco

You can see in the driver's documentation that the maximum current is much lower. One is driving a 3.7 kW motor (200V) with a 7.5 kW Delta driver. It doesn't work well. An alarm is triggered under heavier load. I think you need a much larger driver.


Trying to learn something - not challenging you.

Are you referring to a Y-wired motor being driven by a delta-wired VFD?

Or a Delta-brand VFD?

Assuming the Vevor VFD can output 50A (per spec), why would it be a bad idea not to just current-limit the VFD in parameters?
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17 Jul 2023 15:59 #275656 by tommylight


Assuming the Vevor VFD can output 50A (per spec), why would it be a bad idea not to just current-limit the VFD in parameters?

I doubt it can do 50A, a 11KW Yaskawa does 45A, both are 200V parts, but i might be wrong, new stuff can handle a lot of power.
Spumco is right, limit the current on VFD to 15 or 20A, see how the motor runs, either way your motor can do 32A only for short runs.
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17 Jul 2023 16:01 #275657 by besriworld
Oops, forget what I said. :) I thought we were talking about a 3x400v driver. Now I saw the spec.

"Or a Delta-brand VFD " Yes
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17 Jul 2023 16:14 #275658 by tommylight
You can safely run a 200 or 220V motor through a 380 or 480V VFD, just make sure to limit the current, and always there should be at least two settings for current limiting, continous and peak or short term, those are not the same thing so a bit of reading the manual should help. Also limit the frequency/speed to what motor can safely handle, spindle bearings are very iffy if pushed over, also expensive, very.
Either way, as a rule, start small, half current is ok.

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