Printable View
Hi
Im new to CNC machining and come from a non-electric background , but ive purchased a power supply with connections for only live and neutral wire. Does this mean i wont need my device earthed hence my mains plug has got to only have live and neutral inputs? If so, can i use a spare plug in my house and cut of the earth wire in order to use it?
Thanks
Got a link to a picture of it ?
The link to the power supply is
http://www.leadshine.com/productdeta...model=PS408-12
No, you must mount the supply in a metal box with all the rest of the kit, Bob, drivers, etc. The earth wire goes to a good connection on the box so it forms a protective screen around the kit. Do a forum search for 'star point' for more information on how and why. Never ever run cnc kit without an earth.
The power supply you linked to does not require an earth BUT the case or box that you mount it in will need to be earthed. If you are using this with stepper motors etc. Use screened cables like CY 4 core and connect all the screens at the control box end to a star point (ie one fixed point) and all other earths to that same point including the machine frame, which is then connected to your main earth.Quote:
Originally Posted by Skydeals
If you are not happy with wiring 230V then ask for help from somebody that is. ..Clive
Sorry what do you mean by all the screens and how do I connect all the screens from the control box end to one point. Do I have to use a certain cable?
I think it might be better if you state exactly what you are trying to achieve. The certain type of cable is CY 4 core you can Google it . What are you using the power supply for? Pictures!! ..CliveQuote:
Originally Posted by Skydeals
Ok you''ll have to help me out here. I appreciate your time. Ive not got pictures so ive added links to the parts. Im using the power supply to power 3 drivers , theQuote:
Originally Posted by Clive S
link for the drivers is (http://www.leadshine.com/UploadFile/Down/DM442m.pdf). For the connection from power supply to driver, ill be using the wires from maplin (see link below)
http://www.maplin.co.uk/p/twin-core-...er-metre-xs71n
For the drivers to motors ill be using the cy 4 cable from zapp automation (http://www.zappautomation.co.uk/elec...-cy-cable.html)
Im not sure of the wire to use between my ZP5A- int BOB and driver, and whether this has to be grounded in between the connections.
I havent bought the cy 4 cable yet but i was wondering if all of them come with a wire which is used as ground as well as the 4 wires for driver to motor connection. If so do i connect all the ground wires at the driver end (between driver and motor) to the star point. Am i alright right in the choice of
Ok you''ll have to help me out here. I appreciate your time. Ive not got pictures so ive added links to the parts. Im using the power supply to power 3 drivers , theQuote:
Originally Posted by Clive S
link for the drivers is (http://www.leadshine.com/UploadFile/Down/DM442m.pdf). For the connection from power supplu to driver, ill be using the wires from maplin (see link below)
http://www.maplin.co.uk/p/twin-core-...er-metre-xs71n
For the drivers to motors ill be using the cy 4 cable from zapp automation (http://www.zappautomation.co.uk/elec...-cy-cable.html)
Im not sure of the wire to use between my ZP5A- int BOB and driver, and whether this has to be grounded in between the connections.
I havent bought the cy 4 cable yet but i was wondering if all of them come with a wire which is used as ground as well as the 4 wires for driver to motor connection. If so do i connect all the ground wires at the driver end (between driver and motor) to the star point. Am i alright right in the choice of wires chosen and could you advise me on wire between BOB and driver.
Thank you very much!
Skydeals What steppers are you using?
""I havent bought the cy 4 cable yet but i was wondering if all of them come with a wire which is used as ground as well as the 4 wires for driver to motor connection. If so do i connect all the ground wires at the driver end (between driver and motor) to the star point. Am i alright right in the choice of wires chosen and could you advise me on wire between BOB and driver.""
You need 4 core cy cable I use 1mm but some use 1.5mm the screens (braid) of the cy cable are all connected together at the star point at the motor end the cy cable screen is just insulated ( not connected).
I use cat 5 cable between the BOB and driver (twisted pairs) ..Clive
Thanks!Quote:
Originally Posted by Clive S
Im using Nema 23 (sy60sth88-300bf) motors (link is http://www.zappautomation.co.uk/elec...per-motor.html).
So from what I gather, Ill connect all the screens to the star point from the motor end. Should I use any specific wire for connecting screens to star point?
"Im using Nema 23 (sy60sth88-300bf) motors (link is http://www.zappautomation.co.uk/elec...per-motor.html).
So from what I gather, Ill connect all the screens to the star point from the motor end. Should I use any specific wire for connecting screens to star point?" no just as short as possible. ..Clive
Few pointers other than Star Earth point mentioned.
# Always put shrink wrap on the terminated ends and any connections of the braided shield wire of CY cable as strands of braids can come lose and cause shorts.
# Try to keep signal wires away from power wires much as possible and keep all signal wire runs short as needed and no more.
# Locate the PSU furthest away you can from BOB or devices that take signal wires ie Drives.
# Don't fasten or tie wrap signal wires together.
# Use bootlace ferrules on cables for connections to drives, BOB, etc they make life easier and far better than soldering with less chance of poor connections or broken wires which is a common cause of intermitant problems like drop steps etc.
# Don't daisy chain (series wire) power or signal wires to drives etc always provide them with there own route back to source.
# Minimise any plug connections or wire joints. Plugs and sockets are nice but they are also a source for problems so if you can live without them do so. It's one less area for problems when newness as worn off.!!
# Build the Control box in stages and test as you go along. This way you know which area is giving you the problem and hopefull no magic smoke is released. Best to start with minimal connections so for first test just BOB and drives with no connections to anything like limit switches etc. Then introduce them one at a time then test each before moving onto next.
# Use correct fuses on anything that is expensive and don't over rate the fuse. If you have any doubts when testing the use lower rated fuse than component rating so it blows that first.
##### DONT turn anything on if your not 99.9% sure.!! ##### and Double check everything before doing so.!
Try CSE cables for your CY cable and general wires etc they will be much cheaper than Maplins etc. http://www.csecables.com/acatalog/Fl...rol-Cable.html
All spot on good points. Good luck with the build.:beer: ..Clive
thanks for the info!
No. The screens are connected to the star point at the driver end. The correct way to do this is to separate out the braid and solder onto it some hook up wire (use 7/0.2 or 16/0.2) then fold it back and put 1.5cm of heatshrink over it to 'seal' the end. At the motor end cut the braid off and again 'seal' the end with heatshrink. Keep the unshielded cables as short as you can without straining anything.Quote:
Originally Posted by Skydeals
Attachment 12734
Could you explain why the screen the is folded and also grounded in the following way. its just that it will help me understand the whole picture of wiring then.
thanks!!
Keeping it simple , the purpose of the screen is to keep noise out of the wiring it surrounds or to stop that wiring creating noise elsewhere. It is also protective in the case of high voltage wiring. The screen is connected to the system earth. It's important that the screen is as continuous as possible.
It's also important to understand that the earth is NOT the mains neutral or the DC side ground, and that those circuits must not come into contact with the earth else it ceases to be protective. You can think of it as extending the protection of the metal box further down the wire. As a general rule screens are only connected at one end to avoid creating 'ground loops'. The technique I've shown is a good way to connect the screen, avoid creating short circuits and provide some mechanical strength to the connection.