Re: rod-mill project - "mains" electric motor advice

"Jim Wilkins" <muratlanne@gmail.com> writes:

"Richard Smith"  wrote in message news:m1ldsc42kf.fsf@void.com...
>

If using flat-belts (or any other belt drive) that needs 2
countershafts, for a 3-stage speed reduction?

>
https://woodgears.ca/big_bandsaw/pulley.html
>
...

Hi again

Prices came in on 0.75kW motors = 1HP.

This is all "clean new start" - don't have to fit in with anything
before.

"Inherently" single-phase motor:

1ph 4-pole motor - so on 50Hz is 1500rpm.
Coming in at about GBP160, then tax at 20%


Convert 1ph to 3ph and get 2nd-hand 3ph electric motors:

"Digital" converter - GBP250 for 1HP - then tax.
Is 240V only (GBP420 if can do 440V - "star and delta")
So needs "dual voltage" motor - assured most in last 30 years are (??)
Says - typically fine for one-person user - only one machine at a time
- but can start ancilliaries like pumps etc. after big machine
running.  Not "DOL" - has to be simple switch.
That's about 1HP converter can drive 1HP motor IF the digital
converter does a "soft-start" - and if one motor already running,
cannot "soft-start" the "new" motor (stating the obvious).

Didn't ask if offers speed-control - ability to control over +-30%
range would be a blessing - not have to vary speed with different
pulleys.

The "digital" 1ph-to-3ph is a good brand.

Folk - any guidance?

It would do me a lot of good to get this project done, so I am not
going to sweat this too much - in the absence of being shown the way,
I will likely get the single-phase 0.75kW motor, do the belts and see
this thing running a.s.a.p.
In a lifetime, sometimes it's better to get that next step done and
know all about what you'd do next when it comes around again.

Regards, Rich S