470uf cap?

[Greolt]

I've read that a 470uf 100v cap should be used across the G201's power terminals.
Getting 100v seems difficult localy, will 63v be OK?

Running 260oz steppers bipolar at 42v

Thanks, Greolt

[NC Cams]

It depends what the level of inductive feedback volatage is and how long it stays that high and how often you make the excursion.

Over time, as you go over-voltage on a cap, it is possible to "pop" them...

[Greolt]

So what you saying is the "inductive feedback volatage" will be or can be higher than the supply voltage.

So if I keep the power supply lines shorter than a foot I would be better off without these caps rather than under spec'd.

Greolt

[eidos]

hi
how much amper do they absorb the motors?

43 v feeding > 63 V capacitor ok
microfarad = 2000uf * 1 Amper
in the s. drivers 1000 uf is good
hi

Originally Posted by Greolt I've read that a 470uf 100v cap should be used across the G201's power terminals. Getting 100v seems difficult localy, will 63v be OK? Running 260oz steppers bipolar at 42v Thanks, Greolt

[NC Cams]

Yes, the inductive feedback is usually HIGHER than the supply voltage.

For example, on a 12v car system, some solenoids can "kick back" with almost a 60v spike - the inducted volatage depends on the amount of current flowing in the coil and the amount of turns of wire on same.

Although you may NOT get that high, you ultimately have to protect for it.

I am NOT suggesting that you run without the caps. I'd use the voltage recommended by the drive supplier - the supplier obviously had reasons for specing that voltage (perhaps an idiosyncracy that cropped up in testing). I don't know what if any effect wire length would have on induced voltage.

The recommendations of the drive manufacturer should take precedence over the suggestions of message board members, no matter how well intended or informed.

[Greolt]

OK looks like I must try harder to get some 100v ones.

The gecko manual says they should be added if the lines from the power supply exeed one foot.

As I have yet to mount it all in a case this is yet to be established but I'll get them anyhow.

Thanks for the help, Greolt