Newbie stepper questions
Posted by
Eric Earnst
on 2002-04-07 21:07:58 UTC
Hi all, I've recently started collecting parts for CNC route/mill home
built project and have some stepper questions.
I picked up 4 Pacific Scientific Sigmax E32 series NEMA 34 frame 659
oz-in stepper motors for $40 ea on eBay recently and before I get too
far would like confirmation that they are a reasonable choice. The
catalog says they are a parallel connection, 5.2 A, .44 ohms phase
resistance, 5 mH phase inductance, 4 leads. I suspect they may be
overkill since I am only looking at a table top sized unit so we can
mill PCBs, small aluminum parts for robot/RC projects, etc., using a
Rotozip. From Mariss' FAQ I understand that overkill can be a bad thing
but hopefully it is better than underpowered steppers.
For drives it looks like the 201 is the easiest way to go.
I have been archiving the digest version of the list since 1/00 and I
started going through it last night looking for coupler
recommendations. There was much discussion of zero backlash couplings,
belt drive, etc. US Digital has zero backlash couplings rated (for
shaft size of above motors) at either 42 in-lb or 103 in-lb for only $19
ea. which is way less than what appear to me to be comparable couplers
from other suppliers. Is there something I'm missing that causes these
to be so cheap? As far as sizing goes, using a holding torque of 659
oz-in or 41 in-lbs (?) then does the 103 in-lb version provide enough
margin for dynamic loads?
I haven't settled on the kind of screws to use which impacts the choice
of direct coupling or belt/chain drive. Of course I want as close to
perfection as I can get (whatever that means) and am still pondering the
mechanicals, more email to follow!
Thanks, Eric
PS. If the price for the steppers is good, the seller said he had more,
please contact me privately
built project and have some stepper questions.
I picked up 4 Pacific Scientific Sigmax E32 series NEMA 34 frame 659
oz-in stepper motors for $40 ea on eBay recently and before I get too
far would like confirmation that they are a reasonable choice. The
catalog says they are a parallel connection, 5.2 A, .44 ohms phase
resistance, 5 mH phase inductance, 4 leads. I suspect they may be
overkill since I am only looking at a table top sized unit so we can
mill PCBs, small aluminum parts for robot/RC projects, etc., using a
Rotozip. From Mariss' FAQ I understand that overkill can be a bad thing
but hopefully it is better than underpowered steppers.
For drives it looks like the 201 is the easiest way to go.
I have been archiving the digest version of the list since 1/00 and I
started going through it last night looking for coupler
recommendations. There was much discussion of zero backlash couplings,
belt drive, etc. US Digital has zero backlash couplings rated (for
shaft size of above motors) at either 42 in-lb or 103 in-lb for only $19
ea. which is way less than what appear to me to be comparable couplers
from other suppliers. Is there something I'm missing that causes these
to be so cheap? As far as sizing goes, using a holding torque of 659
oz-in or 41 in-lbs (?) then does the 103 in-lb version provide enough
margin for dynamic loads?
I haven't settled on the kind of screws to use which impacts the choice
of direct coupling or belt/chain drive. Of course I want as close to
perfection as I can get (whatever that means) and am still pondering the
mechanicals, more email to follow!
Thanks, Eric
PS. If the price for the steppers is good, the seller said he had more,
please contact me privately