Need brushless motor model for lathe spindle advice. Is this enough?

[Rimbaldo]

Hi!

I own a micro lathe converted to CNC and working fine, except it lacks torque when parting-off and threading deeper threads. (when the pitch gets close to 1.5mm). I already have a index pulse on the spindle and closed feedback, and 6:1 pulleys for threading. But still I feel the motor is not enough.

My DC stock motor is 150W 210VDC, 4000 RPM max and runs at 0.7A max

I have two set of pulleys (2:1 and 6:1)

I plan on replacing it by a brushless one (with it´s driver), but I´d like to know if the brushless specs are enough for a mini lathe. And it´s torque also.

The motor is 785W, 310VDC, 3000 RPM, 2.5N.m torque.

If I replace the motor, at least one set of my pulleys will need to be re-done, as the RPM is not so fast in this new motor,and the shaft is thicker.

I´ll put in a table all the specs, so you can read it easier:

(Motor Model) LK86BL13031 Number of Phases 4 voltage VDC 310 Rated speed rpm 3000 Rated torque N.m 2.5 Rated current Amps 3.3 Rated power Watt 785 Max torque N.m 7.5 Torque constant N.mlAmps 0.8 Back EMF V/Krpm 62 Rotor inertia Kg.mm2 320 Lenght mm 130 Weight Kg 4.3 Flange mm 86 Shaft Diameter mm 14

Would this be enough for hobby use?

Regards, Rodrigo

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[handlewanker]

Hi.....150 watts against 785 watts....... that is almost 5 times the HP rating.....should be heaps better.

I would adjust the pulleys to give you the 4,000 rpm you want at top rpm as the VFD can put out the torque when the rpm are lower......provided your VFD has the capacity for the new motor.........the AT1 single phase to 3 phase VFD on EBAY is rated at 2.2Kw or 3 HP.
Ian.

[Rimbaldo]

Hi.....150 watts against 785 watts....... that is almost 5 times the HP rating.....should be heaps better.

I would adjust the pulleys to give you the 4,000 rpm you want at top rpm as the VFD can put out the torque when the rpm are lower......provided your VFD has the capacity for the new motor.........the AT1 single phase to 3 phase VFD on EBAY is rated at 2.2Kw or 3 HP.
Ian.

The driver I guess is not an Inverter. I´ll post the manual attached if possible.

My lathe´s 150W motor is rated at 4.000 RPM, but in the original pulley there´s a reduction so it runs at 2000 RPM max. So I guess I´ll change the pulleys ratio to get to 1:1 ratio with this new motor, so it would be at max 3.000 RPM.

I´ll post the link to the driver I found on aliexpress, If you care to see if it´s enough for this motor:https://www.aliexpress.com/item/4000822040540.html

Thanks for your answer!

[handlewanker]

OOPs....my mistake I assumed it was a 3 phase motor hence the VFD reference I mentioned.

If you did go with a 3 phase motor a VFD will drive it with variable speed etc.....speed would ideally be 3,000 rpm and 3/4 HP would be quite adequate and compact.

I can't comment on the motor you mentioned.....don't know enough about them..........probably a brushless type with an ESC to drive it.

My favourites now are 3 Phase motors as they are practically bullet proof......just don't run them too slow for long periods or they overheat...... or use a computer fan attached to the end face.

A 3/4 HP 3 phase motor on EBAY cost me about A$85 and the 2.2Kw (3 HP) VFD was A$80 on EBAY or Amazon.
Ian.