Re: [CAD_CAM_EDM_DRO] new stepper motors wiring mess...

Keith Clark wrote:

>Help again! My repaired motion board, replacement Gecko 210 driver
>and new stepper motors arrived. I assembled them all but installed
>only one stepper motor to the Z axis for testing.
>
>I talked to the Anaheim Automation factory person to get advice on
>the wiring for the Gecko drives and his new motor. It is wired
>bipolar in series and is rated at 4.9 amps. It is one of the new
>square Nema 42 high torque motors.
>
>There are 2 windings wired in series together on one side of the
>motor and another 2 windings wired in series on the other side. I
>was instructed to connect one end of a set of series windings to the
>Gecko phase A and the other end to Phase B then connect the second
>set of series windings to Phase C and D. This is exactly what I did
>on the original Bridgeport motor and the Gecko burned up! I told him
>this but he thought it would be correct.
>
>So on I merrily went according to the plan and it was apparently
>wrong. Luckily I had purchased a backup powersupply for the setup
>and it recognized an overload and shutdown before (I hope) ruining
>the Gecko drive. I wonder if I can just switch Phase B and C wires
>as I did before and get it to run.
>
>I just don't understand why both the Gecko instructions and the
>Anaheim Automation instructions describe the same wiring method and
>it does not work. What am I not understanding here?
>
>

It is imperative when using series or parallel connection that the windings
be connected IN PHASE. If the ends are not connected right, the inductance
cancels out, and the drive burns up.

Here's how to tell: Connect a D cell to where you have the Gecko A and
B wires.
Does the motor become very hard to turn? If not, try switching one of
the winding
half sections. What I mean here is if the 2 parts of the A phase are
labeled
1-2 and 3-4, and you have 2 connected to 3 and the Gecko connected to 1
and 4,
you would swap wires 3 and 4 so that 2 is connected to 4 and wires 1 and
3 are
now connected to the power source (Gecko or battery). If this gives much
stronger holding torque, then you have the winding phased correctly, now.

The advantage of using half winding on an 8-wire motor is you can't run
into this
phasing problem.

If the holding torque is weak, and the above procedure doesn't fix it,
you need
to make sure the two windings connected together are part of the same phase.
Apply the battery to only one half of a phase. Observe the motor jump
position
a little. Now apply the battery to the other half. It will either not
jump at all
or it will. Go back to the first winding, then apply to the 2nd half
but with the
opposite polarity. If it jumps when you go to the 2nd half with EITHER
polarity,
then these are NOT part of the same phase, and should not be connected
together.

Jon