CNC wiring?

[stdly]

I am not electrical and I found allot of this on the web.
I know it is allot to ask but if I could get some feedback on this wiring diagram I would really appreciate it.
It is here.
http://www.pattispawprints.com/pipep...MDX 3 axis.pdf

I already have a few questions to finish this off.

1) I have a light after the PSU board and the voltage is around 43vdc and will vary as I understand so what can I do here?

2) Should I change the fan and relay curcuit to 110? I still need power for the PMDX-122.

3) The diode on the relay coil was something I foun on the web and don't really understand. I guess it has to do with vdc because I use 120vac relays at work all the time and have never use a diode?

4)Is 15 amp On the relay contact going to be enough? I have heard of EMF I beleive and would this be a problem?

5) The fuse on the 120 in line I don't know what amp it should be?

6) I don't quite understand the ground to pin 10 on the parellel port through the E-Stop.

Steve

[Al_The_Man]

1) What is the purpose of the light? work light or indicator? As alternate source could be used depending on purpose
2) You could keep both at 12v
3) ONLY use a diode on DC relays, it is for back emf suppression, on AC relays a resistance/capacitance snubber should be used.
4) The 15amp rating is probabally resistive load, when breaking a heavy DC inductive current, contact arcing and welding can occur, it is often better to break the AC side at the same time, use a multi-pole relay and disable the drives at the same time, if they have an enable input.
5)Depending on the VA of the transformer, I would expect 5amps max.
6) could'nt make that one out on the drawing
Note: Relays that break a heavy DC inductive load are fitted with magnets close to the contacts, called arc blow-out relays.
Al.

[stdly]

Al,
Thanks Agian! I see how you got to be THE MAN!

1) Indicator on the panel. Do I have to go LED with a resistor and if so what type of each or how to calculate it?

2) Can I build this 12VDC. ac relays resistance/capacitance woops!

3) How is the value set?

4) Will do. I thought the DC side because of the stored power in the caps.

5) 500va?

6) It will zoom in nice, but I can ask the PMDX guys I am sure

Note) Do you have a link to an example

Originally Posted by Al_The_Man 1) What is the purpose of the light? work light or indicator? As alternate source could be used depending on purpose 2) You could keep both at 12v 3) ONLY use a diode on DC relays, it is for back emf suppression, on AC relays a resistance/capacitance snubber should be used. 4) The 15amp rating is probabally resistive load, when breaking a heavy DC inductive current, contact arcing and welding can occur, it is often better to break the AC side at the same time, use a multi-pole relay and disable the drives at the same time, if they have an enable input. 5)Depending on the VA of the transformer, I would expect 5amps max. 6) could'nt make that one out on the drawing Note: Relays that break a heavy DC inductive load are fitted with magnets close to the contacts, called arc blow-out relays. Al.

[Al_The_Man]

Here is a forum link that describes the snubber http://cnczone.com/forums/showthread...hlight=snubber
5amp fuse minimum.
If you want DC power status, do your drives have power LED's on them?
I don't have a specific link for blow-out relays, but I know Potter & brumfield have them as I use a particular one of theirs.PRD-11DHO-110
Al.

[stdly]

Originally Posted by Al_The_Man Here is a forum link that describes the snubber http://cnczone.com/forums/showthread...hlight=snubber 5amp fuse minimum. If you want DC power status, do your drives have power LED's on them? I don't have a specific link for blow-out relays, but I know Potter & brumfield have them as I use a particular one of theirs.PRD-11DHO-110 Al.

Thanks! I am using Gecko's but they will be in an encloser. The light was just flash for certain people to enjoy and it would tell me I have DC out of the PMDX power board.
Every bit of electronics I bought seems to have led's but with an encloser what good are they?
Maybe I will cut out the front of my encloser and add a piece of plexi glass for visual on these led's.
Or maybe a flashing led fan (not)!!!

[stdly]

Originally Posted by Al_The_Man 4) The 15amp rating is probabally resistive load, when breaking a heavy DC inductive current, contact arcing and welding can occur, it is often better to break the AC side at the same time, use a multi-pole relay and disable the drives at the same time, if they have an enable input. Al.

Al,
How about 2-25 amp electronic relays would they take the load better without the chance of welding the contacts.
Steve

[Al_The_Man]

I think you would be better off relay switching the AC to the power supply, switching the DC, There is nowhere for the back emf to go so it could damage your amplifers.
Al.

[stdly]

Originally Posted by Al_The_Man I think you would be better off relay switching the AC to the power supply, switching the DC, There is nowhere for the back emf to go so it could damage your amplifers. Al.

Al,
Thanks!
I just thought that the parellel port card has a charge pump cicuit and an e-stop that stops sending step & direction signals to the motor drive but the vdc is still going to the motor? from the charged caps?
Can the motors keep moving without the signals and just the cap charge. Does this last long with a motor attached to it though?
I have heard of run away servos but not run away steppers so maybe this would only be an issue with a servo system?
Steve

[Al_The_Man]

Thats why if possible you should also disable the amps if they have an enable input on them, it just means a multi-pole relay.
Al.

[stdly]

Originally Posted by Al_The_Man Thats why if possible you should also disable the amps if they have an enable input on them, it just means a multi-pole relay. Al.

Al,
I don't understand what you mean by amps/amplifers. I am using gecko's as I show in the diagram. Could you expand on this a bit please?

[Al_The_Man]

I have never used these amps (Gecko's) so someone like Gerry may be able to inform you better, but if you notice they show an enable input, If used this should be able to shut off the amplifier in case of a fault, The data sheet should tell you how to use it and if it is active high or low.
Al.

[stdly]

Originally Posted by Al_The_Man I have never used these amps (Gecko's) so someone like Gerry may be able to inform you better, but if you notice they show an enable input, If used this should be able to shut off the amplifier in case of a fault, The data sheet should tell you how to use it and if it is active high or low. Al.

Al,
OK the Gecko is the amp. I will check the data sheet. Thanks!
Steve