New salvage steppers

Been struggling to get started really - did find some new stepper motors today in the car park on some salvage copiers. Should be good for the CNC milling machine I am planning on to produce the parts for a reprap. Plan is a Sieg X1 home CNC'd to make the parts for the reprap.

These motors are pretty beefy - havent had a chance to lookup any data on it but did notice they have encoders built on the back end which may or may not be of any use?

8mm shafts dont know the voltage or current yet but should be ok for a small CNC mill surely? Mounting holes look like 47.5mm apart

Hi John,

... good findings

The motors should be enough for a small CNC-machine - you can measure the resistance of the coils for first estimates of the support-voltage.

Encoder could be usefull too ... if not, then you have a second shaft

Viktor

looks like a nema23 with a 1600 count per rev encoder on the back.. encoder looks like an avago aeds-9641-P10 or similar, see [www.avagotech.com]

what's the winding resistance and inductance on that stepper?

all up an extremely nice find I think

Odd for a stepper to be fitted with a shaft encoder in a product like a copier. You might have a servo motor, although I would expect 3 wires in that case.

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[www.hydraraptor.blogspot.com]

So this stepper drives a controlled pressure nip which I believe is why it has an encoder, its off a large inkjet rather than xerographic machine.

The resistance between the coils is 0.4-0.5 ohms - my meter isn't precise enough. I have asked the guys responsible for that area of the copier to send me the drawing and specs for it so I know what it really needs.

I have 5 of these now, so should be all set.

Very nice find then, looks like it is wound for high speed.

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[www.hydraraptor.blogspot.com]

Most of the steppers we use in our machines are high speed 24v efforts - but at 0.5ohms I seriously doubt its going to be 24v as that would be 48amps right?

Hopefully I can get the drawing tomorrow.

[www.diycnc.co.uk]

These look like a cost effective alternative to the V2.3 electronics since you cant seem to get them assembled in the UK?

They are more like the V3.0 that is not released yet.

Odd the kit is more expensive than the ready assembled.

Low resistance motors are designed to be run from constant current chopper drives like the above.

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[www.hydraraptor.blogspot.com]

Blimey the chip is nearly £7 from Farnell and Digikey I got some v2.3 boards and some 3982 chips a while ago that I haven't built up yet but I recall that driver being around £3.50.

I did try one with solder paste and it never worked proper - so i'll hand solder it in a bit and take it to work tomorrow to test!

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JohnW
Blimey the chip is nearly £7 from Farnell and Digikey

yeah it's expensive for a chip, but consider what it would cost to do the same thing any other way and it starts to look far more attractive.

Well a mega8 and 8 FETs or an Hbridge could be had for < £3 and be easier to proto and deal with much more current and voltage?

Quite a few projects on AVR freaks ready to go so no coding required either.

And if you went up a bit in chip you could probably run all three axis on one MCU.

Hmm, interesting.

Was exercising using a 2.3 stepper driver - set the current limit to 0.5A, going clockwise it was fine. Changed it to anti-clockwise and after about 3-4seconds it blew the board.

I thought the funny smell was the soldering iron Never mind.