PS caps and fuses

[stirling]

There's been at various times a couple of discussions over on the Mach forum re: whether or not to have quick blow fuses between the PS and drives and whether or not to have a large capacitor between a switching PS and the drives.

I have a copy of the (famous) STEP MOTOR BASICS guide which is a few years old now and it states YES to both the above questions.

However, all be it divided opinion seems to be NO to both the questions and indeed one poster says Mariss has argued against the use of fuses between PS and drives for years.

I notice that these sections have both apparantly been dropped from the latest STEP MOTOR BASICS guide on the Gecko site.

However the thread at the top of this sub still refers to a filter cap but doesn't state (like before) that it should be used with a switched supply so is perhaps ambiguous maybe. Also, further down, fast blow fuses are recommended.

Hence I guess the confusion. Has Mariss been mis-represented? Is there a difference of opinion between Marcus and Mariss? Do we fuse or not? Do we use caps with switching supplies?

Thanks

Ian

[Scottluther]

Well, I have been looking to get an answer to the fuse sizing for my gecko 251Xs. If you look on the gecko site, FAQ, under fuse recommendations, it says that slow blow fuses may not save your drives and to select an amp rating that you don't want to exceed. Well duh? The question is how to figure that out. (they have a comment in parenthesis too... 7amp for steppers, 20amp for servos). My confusion is I thought the fuses were for the drives. The drives are rated at 3.5 amp, but that's output. Docs only list warming for exceeding voltage limits. So what are the amp limits for fuse sizing?

[Jackal66]

Here is a link on fusing.

These guys helped me out a lot.

It will help you decide.

http://www.cnczone.com/forums/gecko_...ecko_320x.html

Hope this helps,

JAckal

[stirling]

Thanks JAckal - excellent info.



Ian