Re: Source for stepper motors....

Hi,

We get motors from OEMs that want their step motors characterized
(dyno-tested for performance) with our drives. The deal we strike
with these OEMs is "you get the data, we keep the motor".

For that reason we have about a hundred recent vintage motors, 1 or 2
of a kind, that we have tested for all kinds of characteristics like
power output, efficiency, linearity, accuracy, etc, etc.

Three motor manufacturers stand out; Pacific Scientific, Vexta and
Sanyo-Denki. Specifically these are the PacSci "PowerPac" K30 series
for NEMA-34 size, the Vexta PK268 series and the Sanyo-Denki "Step-
Syn" 103H series for NEMA-23 size motors.

All of these are the "square" or cruciform-shaped motors. I wouldn't
recommend any "round" step motor today except for a very few of the
older Superior Electric, (now Danaher) motors that curiously were
very smooth (M062-FD04).

Most "square" motors have a modern magnetic flux design that takes
full advantage of microstep drives that the older "round" motors were
never designed for. This means these motors have the rotor accurately
follow the vector angle of the phase currents and a torque that is
proportional to the vector sum of these currents; i.e. they have very
good linearity (>1%) when driven by a low harmonic distortion drive.

In fact these motors are so good you cannot tell them apart from a
servo motor at low speeds; they are totally absent any low-speed
resonance or vibration.

The very best are the PacSci motors and my understanding is you pay
for it as well; their prices are probably out of the range most
hobbyists would want to pay.

The Vexta motors are somehere in between in price and they are as
good as the Sanyo-Denki motors.

The best value seem to be the Sanyo motors. I was surprised by our
test results of the quality and performance of what has the
reputation of being a "cost conscious" manufacturer. They are
extremely good motors.

Coincidentally I was cold-called by a someone named Darrell Paul
representing Enprotech Autromation Services Inc. that resells Sanyo-
Denki motors in Michigan. He offered, (and I declined) renumeration
for leads; I don't need or want the entanglements.

I talked to him for awhile and explained anyone I sent his way wasn't
going to order a thousand motors and he was OK with that. He seemed
like a nice guy and he immediately gave up pricing, (a good thing)
which seemed very competitive to me (about $80 single quantity, NEMA-
23).

The only reason for mentioning this is (A), they are very good motors
and (B) the Sanyo-Denki site is too dense to wade thru to find
someone who can actually sell you a motor.

Sorry for what seems like a sales pitch. I get nor need anything for
it except to point someone where they are looking to go.

Mariss

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Ross" <rrcarl@n...> wrote:
> Hi all...
>
> Has anyone got a source for new stepper motors. I need 6 wire
motors around 500 oz/in with per phase current less that 4A.
>
> Thanks...Ross