Re: twisting motor cables

--- In CAD_CAM_EDM_DRO@y..., "caudlet" <tom@t...> wrote:

> The twisted wire thing is based on the fact that noise and

crosstalk

> (to other parallel wires) on a pair of wires tend to cancel out

when

> wrapped in a "twist". This also helps in making the pair more

noise

> immune from external sources if the circuit is a "differential"
> input. Just taking all the wires for a motor and twisting them
> together will do little to cancel anything. The twist should be
> a "pair" of wires. That means wires that make up a complete

circuit

> from a current perspective. The A set of wires (+ & - ) would be
> twisted tightly together. The B set should be a seperate twist.

It

> is more important that any signal wires (step, direction, encoder
> feedback) be either shielded or twisted or both. If you use

shielded

> then ground one end only of the wire.

Would it be correct to say that signal line are more suseptible to
noise because it is only 5V while the motor cable may be way above,
say, 30V? What about motor cable as a source of noise?

> a "pair" of wires. That means wires that make up a complete

circuit

One of the pair goes to ground. Does the return current always return
via th other pair, or is it possible that the return current may go
via any of the numerous other ground wires?

Thanks

Lee