Steppers for Converting Sieg X2 to CNC?

[Cret]

Here you are:


Straight through shafts as well (they're 6.3mm) so potentially can still have manual control.

They're 6 wire ones but as I understand you just omit the centre tap wires for each coil to use as normal 4 wire ones, depending what the controller/driver actually needs.
47mm between mount holes, which I understand is the normal pattern for Nema23.

[irving2008]

6 wire explains why they'll be so poor. Designed for unipolar drivers. Yes you can run them on a bipolar driver by not using the centre connection but that's essentially bipolar serial which is the highest inductance, lowest performance.

The other point to note is those drivers will have to be set to 1.8A as the next setting is 2.5A and the steppers are rated at 2.1A. You might get away with the higher setting but they will get very hot. At 1.8A setting you've lost 15% of the little torque you had.

But give it a go, you can always replace them with proper steppers later. :)

[Cret]

Thanks, that's useful info on the current settings. I think I've got fans that might fit on these in the same box but will check.

I don't mind replacing in due case as they were free, but useful for getting something assembled hopefully and testing on principal that the whole setup will work.

Does anyone happen to know if there is such a thing as free .stl files for mounting hardware?

Wushful thinking I suspect!

[stirling]

If you ignore the centre taps then you'll be wiring them full-coil bipolar - this will double the resistance giving a rated current of just 1.05A.

You'll get more torque from these motors if you wire them half-coil bipolar. i.e. use the centre taps and ignore two end coil wires. Then the rated current will be the 2.1A stated.

[dazza]

ive got a complete syil kit(electronics only) I may let go if you or anyones interested that's all the electronics plus the nema 34 for the z and the 2 nema 23 motors the electronics are in a makeshift control box(pc case) all wired up just requires the motors to be rigged up,the kit came off an x3 the specs can be seen here
https://docs.google.com/file/d/0B_5R...wtUGxvVW8/edit

[Cret]

Could be tempted potentially, thanks, but I'll look up the details and see what it all is.

[Jonathan]

You'll get more torque from these motors if you wire them half-coil bipolar. i.e. use the centre taps and ignore two end coil wires. Then the rated current will be the 2.1A stated.

True at 'high' speed, but rated current through half the number of turns - so less flux which means less torque than bipolar using all the coils.

Useful summary here:
UniPolar vs BiPolar wiring schemes for 2-phase Stepper Motors

[irving2008]

If you ignore the centre taps then you'll be wiring them full-coil bipolar - this will double the resistance giving a rated current of just 1.05A.

Actually the current wired bipolar series is 0.7 * rated = 1.47A, so those drivers would need to be run at 1.2A, but the holding torque is 1.4 * rated.

So assuming they are 1Nm (141ozin) motors:
Bipolar 1/2 coil: Rated 2.1A, run at 1.8A, torque = 1.8/2.1Nm = 0.85Nm (120ozin)
Bipolar Series: Rated 1.47A, run at 1.2A, torque = 1.2/1.47 *1.4 = 1.14Nm (160ozin)

So run them Bipolar Series since you'll get low feed rates anyway due to leadscrew inertia and frictional load...

[irving2008]

ive got a complete syil kit(electronics only) I may let go if you or anyones interested that's all the electronics plus the nema 34 for the z and the 2 nema 23 motors the electronics are in a makeshift control box(pc case) all wired up just requires the motors to be rigged up,the kit came off an x3 the specs can be seen here
https://docs.google.com/file/d/0B_5R...wtUGxvVW8/edit

There's a big issue with those drivers - the current setting is not via switches but by twiddling a variable resistor while measuring the current in the windings. That's not easy to do without appropriate test equipment, a cheap digital multimeter on DC Amps setting will be wildly inaccurate as it cant sample fast enough

[Jonathan]

There's a big issue with those drivers - the current setting is not via switches but by twiddling a variable resistor while measuring the current in the windings. That's not easy to do without appropriate test equipment, a cheap digital multimeter on DC Amps setting will be wildly inaccurate as it cant sample fast enough

One might be better off in that situation measuring the supply current and voltage to the driver, then since you (should) know the resistance of the motor at low speed, the required supply current can be estimated fairly accurately by considering the rated power. Adjust the potentiometer to get that current. The supply current should be measurable accurately using a cheap meter due to the filtering effect of the DC-bus capacitor.