1200mmX900mmX170mm 4axis cnc

[driftspin]

Can anyone suggest how to connect relays and fuses at this wiring diagram?

Hi Nick,

I have a primairy CB 16amp C type for the entire cabinet.

I have a CB 4Amp on the 230volt side of the 24vdc 2a supply. PSU secundary is shortcicuit protected.
But maybe an extra 24volt side glass fuse would be appropriate there.

The above CB's are for convienience only.


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.

Shorting out 72vdc circuit can lead to higher amps than i can trust some of the 1mm2 cabinet wiring with.


Since you have 5vdc onboard on ub1 no problems there.


For the relays.. is this about the e-stop relay we talked about?


Can you list the stuff you want to control by relays? You mentioned an ub1 has 3 onboard so...


Maybe pneumatic valves, pumps , vfd?

What needs switching on/off more than the 3 relays available to you?

I would use the onboard relays just for low current stuff like the remote on / off for the vfd , the spindle cooling pump, maybe chip clearing air valves and or liquids.

BTW doesn't your design allow for 4 combined end / home switches?

Do you plan on using all 8 off them?

like 4 home and 4 end?

I read about this a few times on the forum they can be combined in some configurations.

I have no hands on experience this subject (and a lot of other things) :-) yet.

Grtz Bert.



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[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]

For the relays.. is this about the e-stop relay we talked about?


Can you list the stuff you want to control by relays? You mentioned an ub1 has 3 onboard so...


Maybe pneumatic valves, pumps , vfd?

What needs switching on/off more than the 3 relays available to you?

I would use the onboard relays just for low current stuff like the remote on / off for the vfd , the spindle cooling pump, maybe chip clearing air valves and or liquids.

Hi Bert
Thanks for the reply.

The relays that the card has onboard are charachterized as ''signal relays that should never used as power relays, they are intended to convey signals such as fwd and reverse to a VFD ...However please take care , as the contact of these relays can carry a max current of 0.5 amp at 120V AC or 1 amp at 24V dc.The user must use an external relay if the load requirements of the device will exceed the current rating.''

This is why i mention the external relay connection.
To answer the other question you put, I want to connect the maximum I can on this card ,water pump , air nozzle etc.

BTW doesn't your design allow for 4 combined end / home switches?

Do you plan on using all 8 off them?

like 4 home and 4 end?

I read about this a few times on the forum they can be combined in some configurations.

I have no hands on experience this subject (and a lot of other things) :-) yet.

Grtz Bert.

Verstuurd vanaf mijn SM-A320FL met Tapatalk[/QUOTE]

I am going for this configuration because my previus cnc was wired like that, if there is a better way of course I prefer it.

You are speaking about traveling proximity switches, right?


Regards.
Nick.

[driftspin]

Hi Bert
Thanks for the reply.

The relays that the card has onboard are charachterized as ''signal relays that should never used as power relays, they are intended to convey signals such as fwd and reverse to a VFD ...However please take care , as the contact of these relays can carry a max current of 0.5 amp at 120V AC or 1 amp at 24V dc.The user must use an external relay if the load requirements of the device will exceed the current rating.''

This is why i mention the external relay connection.
To answer the other question you put, I want to connect the maximum I can on this card ,water pump , air nozzle etc.






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I am going for this configuration because my previus cnc was wired like that, if there is a better way of course I prefer it.

You are speaking about traveling proximity switches, right?


Regards.
Nick.[/QUOTE]Hi Nick,

Ask/look around for the multi channel relay boards.

For the proximity switches.

You have the inputs for it... so why not


Grtz Bert.

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