Electronics for New Machine + Chinese Spindle + VFD

[mturneruk]

Jazz. Obviously I am listening. I am reading every word 5 times!
Obviously I am working within a budget, but I want to do things safely, and I admit I no electronics engineer, so i am asking for help...

I still can't understand the need for additional breakers or fuses in the box when the chassis power connectors have fuses built in.

On my last machine i had the E-stop wired to my BOB, however i was using a router which had it's own on / off switch. The VFD seems to of complicated everything massively.
So i would appreciate you telling me how i could wire a safe E-Stop.

Chatting to that chap about his cramped case, he said he had 2 48V fans which keep everything cool and it had all been running fine for 2 years plus.
I was thinking i would do the same.

None of you are saying i would have an EMI issue, rather more a heat issue which should be able to be controlled with fans, should it not.
Thanks again.
Martin

[JAZZCNC]

I still can't understand the need for additional breakers or fuses in the box when the chassis power connectors have fuses built in.

Ok Ill explain. So your Incoming Chasis power has you call it is providing power to the drives which all pull a certain amount of current. Lets say 4A each then you have other items possibly pulling off it taking few amps more so your Incoming suppy needs to be fuse rated to handle all this load plus a little spare so it will probably have 13A fuse.
Now what happens if say one motors blows up and shorts out.? Then drive will Pump current to that motor upto the Max the PSU can provide or until the fuse blows which will be much more than 13A. Now the drive is only rated upto 7A so it goes up in flames.!!! . . . Well not really but it does release the Magic smoke and your out of Pocket £50 just because you didn't fit a 50P fuse.. .

I will help you to do this correctly but I'm a little busy just now but I will come back with a Diagram to help.

Edit: Give me a list of everything your putting in the Case.

Regards Space then yes it's mostly heat related so if your sure you can remove the heat correctly then fine but just because he's not had problems doesn't mean you won't. Electrical components need a certain amount of air flow to cool correctly and any restrictions on cooling will have an affect long term. Or on performance.!!

[mturneruk]

Thanks Jazz

I am after simple and safe!
I understand how to wire the steppers. Just not 100% on the e-stop, additional fuses you mentioned or grounding.

2 x chassis power connectors (plugging into 2 plugs).
1 x EMI Filter on VFD Supply.
1 x VFD

1 x 48v Power supply
4 x stepper drivers
1 x UC300 USb motion controller
1 x KK01 Breakout board

1 x Estop
2 x 48v Fans

That's it.

[dodgygeeza]

The Estop should ideally be wired to an emergency relay, that will cut off the AC going to the 48V power supply and also the VFD.
It will also send a signal to the Bob that the Estop has been activated.

Connecting the Estop to the BOB and having your software control the Estop is a no no.

Thanks Jazz

I am after simple and safe!
I understand how to wire the steppers. Just not 100% on the e-stop, additional fuses you mentioned or grounding.

2 x chassis power connectors (plugging into 2 plugs).
1 x EMI Filter on VFD Supply.
1 x VFD

1 x 48v Power supply
4 x stepper drivers
1 x UC300 USb motion controller
1 x KK01 Breakout board

1 x Estop
2 x 48v Fans

That's it.

[JAZZCNC]

I am after simple and safe!
I understand how to wire the steppers. Just not 100% on the e-stop, additional fuses you mentioned or grounding.

Ok but you will need a few more bits.! . . . Nothing expensive but important to have. Momentery Reset Button and Some Relays. Plus if you want a best noise immunity then a 24V PSU.
I also suggest you buy a 5V PSU and power the Uc300 and KK01 from this and don't rely on USB to provide power. This will give you a much more stable system.

The VFD doesn't actually need to be pluged into another plug either if you don't want. I think your probably doing this because of something I said before but miss understood what I meant.?
When I said ideally Run the VFD on It's own Mains Line. I ment on separate Ring Main line not Different Plug line. All your sockets in the room and possibly house will run off the same Ring Main line so doesn't really matter if in same wall socket or across the room in another socket any noise will transfer to/from the VFD to other devices if bad.
Often this isn't possible or practical and why I said "Ideally" so in your case if you like you can just run from one plug socket. Then we Fuse them separate in the case.

This is what others are trying to tell you in that by the time you have put in these extra Fuses, relays etc which are minimum and needed for a truely safe system then you probably won't have enough room.!!
Also Don't let anyone tell you that Software driven E-stop system is safe and you don't need relays etc because it isn't and they are idiots to run without it for what little it costs to do right.

[njhussey]

Martin, don't underestimate how much more powerful this machine will be compared to your last one. When I built my machine I had it upright on it's end whilst I was attaching the Ali base. Whilst it was there I stood on the gantry and just like unscrewing a bottle top was able to turn the ballscrew and lift my weight (19.5 stone) with no effort at all. Now I know that if I accidentally get an arm/finger/leg(!!??) stuck/trapped whilst trying to hold something down (I know, I know, I know you shouldn't do it but.....) then I know for sure that if I press the E-stop I want it to stop dead 100% guaranteed...not be reliant on software to do it for me....

It all comes down to what you want to do safety wise really, have you given any thought to what you want the machine to do in the event of a brown trouser moment? As Dean says, for another £30 or £40 you can have a much safer system.

[mturneruk]

Here's what I have so far...

Plan is to put 2 50mm fans in the top of the case which will blow air directly onto the drivers / VFD into the case and out through the side / bottom vents.
I have mounted the control panel from the VFD on the front of the case.
I may leave the front cover of the VFD to allow more air into it.

This case is easy to work on as you can detach panels and put them back as required.
I wish it was a bit bigger, but as long as you think I wont suffer from EMI issues, then hopefully i will get away with it.
You may of course completely disagree.



Cheers
Martin

[mturneruk]

Thanks again for your help chaps.

It seems sensible to have the whole system shut down when e-stop is pressed. I would agree that it's a basic safety requirement.
So the next question is how to do that with a relay?

Jazz.
5v transformer in the box sounds sensible. I should be able to get a very small one. This could also possible run the case fans instead of 48v.

I think I understand what your saying about having one plug socket.
I would love to use one socket, but I was told to use 2 plugs by someone else at CNC4YOU so as not overload the wall socket. I thought 13A was the max?
Isn't the VFD using 8amps ish and the steppers / 600w power supply using a load more. E.g. Taking the load over what you can pull from a standard house socket?

EDIT : Can anyone confirm how many amps should be allowed for VFD driving spindle + 600 watt power supply driving stepper motors?

Obviously it's confusing on the forums, cause you have a load of guys talking about 3 phase and it's hard to tell what's what.
I thought I knew what i was doing. Obviously not.

If I have to scrap the case and get / make a bigger one I will (Or i might just take the VFD out into it's own box), but it would be nice to get it all in one.

Cheers
Martin

[Clive S]

Also have you thought about sucking all the dust into the control box

[mturneruk]

Thanks Clive.

Yes. It's not to bad as I have an extractor. Bear in mind this is a hobby machine, it's not going to be running all the time.
I hoover up as i go along as well.

Cheers