1200mmX900mmX170mm 4axis cnc

[Clive S]

I still want a 16amp B type CB on secundary side 72vdc psu.
Mine is a high amp (10amps nominal) psu 500va transformer... and would like to protect the wiring in the panel.

Why would you want a 16 breaker on the secondary side Just a slow blow fuse to each drive is more than enough.

[driftspin]

Why would you want a 16 breaker on the secondary side Just a slow blow fuse to each drive is more than enough.

Hi Clive S,

Like i said.. most cabinet wiring is 1mm2.. a bit on the thin side for maximum current the 500va 72vdc psu can generate.
And nothing to stop it .... yet.

I did run separate wires to all drives.
So i could do 4 fuses. 1 per drive.
like these

https://goo.gl/images/zFDM82



Or 1 cb for all..


Grtz Bert.




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[Clive S]

The only thing the 72v ps is supplying is the drives so what has the 1mm wiring got to do with it. Also 1mm cable can carry in the region of 10A

[driftspin]

The only thing the 72v ps is supplying is the drives so what has the 1mm wiring got to do with it. Also 1mm cable can carry in the region of 10A

Hi Clive S,

yes that is exactly the point.
Normally the current will not go past that, my 1mm2 will only carry power to 1 driver.


Until something goes wrong that is.

When a short happens on a transformer it is capable of more current.
It might smoke my 1mm2 panel wiring i believe.
But maybe the rectifier will blow out first.

In my line of work the secundary fuses also match the spec of the panel wiring.

So i think a secundary fuse might be a good idea.


While is was looking up data on my particular transformer, the datasheet mentions the precense a TCO in the primary windings... so transformer thermal overload is sorted.



Can't find any specific data on max fault current though..
Maybe it can be calculated ... not my field of expertise.

Grtz Bert.



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[Davek0974]

Hi Clive S,

yes that is exactly the point.
Normally the current will not go past that, my 1mm2 will only carry power to 1 driver.


Until something goes wrong that is.

When a short happens on a transformer it is capable of more current.
It might smoke my 1mm2 panel wiring i believe.
But maybe the rectifier will blow out first.

In my line of work the secundary fuses also match the spec of the panel wiring.




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your panel wiring really must be able to handle the breaking current of whatever the protective device takes to blow, a slow blow fuse is ideal here, but the wire must be rated suitably - if too thin it will just melt.

[Nickhofen]

One more add on my diagram.Relay and reset switch.

[Nickhofen]

Finish this today!
No cnc relevant , but since I am a sissy as a friend from NY says, to start my wiring,(When someone has not pay a euro for components see it different,LOL), I build other things!