Translating the Phases of a motor from A,C,B,C to A, A(bar) ect..

Other Hardware Motors, Mechanics, Power and CNC
1

Hi all,

I have found that alot of people use the notation of A and A(bar), B and B(Bar) when referring to stepper motors. Can someone please assist me in understanding how this notation translates to the wiring diagram of a 4 wire Bipolar motor such as in the following link for example?

http://www.australianrobotics.com.au/sites/default/files/SM-42BYG011-25.pdf

Thanks in advance

Anu

2

I assume A and A(bar) represent the two ends of the same coil.

...R

3

Hi, A and Abar, B andBbar are referred to when you are discussing the output of pulse encoders,
The difference between A and Abar is that Abar is the inverted signal of A. The bar refers to the negation sign on top of the A'
_
A this is A bar.
so Bbar is the inverted signal of B and so on.

I have not come across this in stepper motors, they usually define the start and end of windings which is important and that is done with a DOT on the diagram.

4

Thanks for your replies Robin2 and TomGeorge. I think i understand this a bit better now.
I also came across the following resource, although there may be an error in the page (under Stepper Motor Coil Windings) where B- should be D i think.

http://www.hobbycncaustralia.com.au/Instructions/iI9wirestepper.htm

Thanks for your assistance.

Anu

5

Windings are usually given letters, so for a common stepper you have A and B windings,
for a three-phase motors there are A, B and C (though some people use
U, V, W for no readily explicable reason). A five-phase stepper has A, B, C, D, E.

Sometimes windings are separate, so each winding has two wires, and these are
labelled A and A-bar (or A+, A-) etc. Typical 3-phase motors have 3 wires in total,
since they are connected star or delta internally, but in theory they could bring out each
separately with 6 wires total.