Bipolar or Unipolar?

Bill Chennault

All--

Can anyone tell if this Jameco NEMA Frame 17 stepper is a bipolar or unipolar stepper? It may be obvious from the Jameco description to someone knowledgeable about these things. There is also a link at the Jameco site to the data sheet.

It looks like both of Parallax's stepper controllers have the current capacity to handle the Jameco stepper. And, the Parallax·BiStep controller will drive two steppers of either type, but with reduced current draw. However, to me it still looks healthy enough to handle a couple of the 400ma Jameco steppers linked to above.

So, which Parallax stepper controller do I need? Either?

Thanks.

--Bill

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You are what you write.

Chris Savage

Bill, it looks like a Bi-Polar Stepper Motor to me. Take care.

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Chris Savage
Parallax Tech Support

Bill Chennault

Chris--

Thank you.

If you have the opportunity, can you tell me if the fact that it is "two phase" told you or if you "read" the "datasheet", specifically looking at the coil·wiring diagrams?

--Bill

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You are what you write.

RDL2004

It's hard to tell for sure, but it looks like the data sheet says it uses winding f (wdg.f). Those are not center tapped, so that would make it bipolar.

Man, that is one of the most poorly reproduced data sheets I've ever seen for an item somebody was trying to sell.

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- Rick

Chris Savage

Bill,

I did base my answer on the 2-phase description. You can also make a fair guess by the number of wires. Usually 4-wire units are Bi-Polar and 5 or 6 wires are Unipolar 4-Phase. Of course you should always verify information before making a purchase. Take care.

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Chris Savage
Parallax Tech Support

Larry

the Two Phase designation won't tell you if it's uniploar or bipolar. You need to count wires and look at the diagrams

I can't tell for sure if it's an "f" coil or an "i" coil winding on the spec sheet. I think it's an 'f' , then I agree with Rick and Chris it's bipolar.

Even if it's an "i" winding, it can still be used in bipolar mode by ignoring the common wires.

So if you want to order the controller and the steppers at the same time, order bipolar.

for future reference, some steppers can be used in either mode

4 wires-- bipolar only
5wires-- unipolar only
6 wires-- either mode- ignore the common wires for Bipolar
8 wires-- either mode- the most flexibility in driving

for the ultimate explanation on steppers, go here

www.cs.uiowa.edu/~jones/step/

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Bill Chennault

RDL4000, Chris, and Larry--

Thank you very much.

Larry, the link to the excellent tutorial is much appreciated.

--Bill

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You are what you write.