Re: anybody have info on laguna lathe?

Ralph E Lindberg wrote:

The use of a DC motor is enough to tell me I don't think I would be
interested. They have torque issues at low RPMs (Plus I think Laguna is
consistently over priced)


I'm not an EE but here goes

I used to make jewelry and a flex shaft with a range of handpieces.
I started out with an AC Foredom motor with a carbon pile foot pedal
for varying speed. At low speeds it had almost no torque. I
switched
the foot pedal speed control to a wire coil rheostat hoping to gain
low speed torque. Didn't work as far as I could tell. So when
Foredom came out with a DC motor and rectifier foot pedal I tried
again. That did the trick. Good torque at about 100 rpms, not
noticably different from full rpm torque.

Second anecdotal evidence - Fisher Paykel washing machine uses a
DC step motor attached directly to the wash tub - as opposed to
the old transmission system of the AC motor approach. The FP
unit has a variable spin speed. A full load of damp clothes requires
a fair amount of torque to start to spin that weight - and the FP
has no problem doing it - with no clunking tranny - and spinds up
to pushing 1000 rpms. Clothes come out nearly dry BTW.

Third anecdotal evidence - electric cars - their motors are DC.
Accelleration requires low end torque initially - and there's a
0-60 mph in under 6 seconds out there now.

So I'm not sure what DC speed control you've got experience
with but my experience hasn't been what you mentioned.

Re: Laguna Tools prices - their main income is from professional
production machines. Their hobbyist stuff is the low end of their
product line. BUT - when they put their name on a machine it's
one they spec'ed or an available one that meets their specs -
which are typically pretty high. They want to sell a machine
to a customer and only hear from the customer when they
want to buy additional machines or upgrade their machines.

charlie b
.

Relevant Pages

  • Re: Sizing Stepper motors for CNC
    ... the motor turns faster provides no more torque. ... Essentially a stepper is a constant power device over most of it's speed ... It seems that 1) power is everything and 2)for a given motor, ... Hopefully I'll get reasonable low speed power for cutting, a reasonable fast feed traverse and something to play with in terms of supply voltages and speeds. ...
    (uk.rec.models.engineering)
  • Re: Variable torque motor for belt grinder ?
    ... Describing a single speed motor as such makes no ... Driven by a VFD, the motor should produce essentially constant torque from ... speeds below 50% are available for detail ...
    (rec.crafts.metalworking)
  • Re: RPM of variable speed DC Motors
    ... I've never heard of anyone calculating amps per RPM, ... then motor A is slightly more ... some manufacturers do not make finding their torque graphs readily ... you'll be able to get nearly that torque out of it at higher speeds (and ...
    (rec.crafts.metalworking)
  • Re: Sizing Stepper motors for CNC
    ... the motor turns faster provides no more torque. ... Essentially a stepper is a constant power device over most of it's speed ... It seems that 1) power is everything and 2)for a given motor, ... lower powered motor would be capable of delivering higher speeds, ...
    (uk.rec.models.engineering)
  • Re: Variable torque motor for belt grinder ?
    ... VFDs allow you to have a pretty wide range with constant torque. ... Assuming you feed a VFD via 220V 20A circuit, ... got the 3 phase 1.5 hp baldor motor off ebay for $30, ... RPMs, the torque will be lowered as well, but you'd need lower speeds ...
    (rec.crafts.metalworking)