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Author Topic: Power Supply Unit  (Read 44423 times)

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Offline kolias

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Re: Power Supply Unit
« Reply #50 on: January 13, 2011, 09:09:08 AM »
No one can help with my previous post?

I would like to know if the transformer looks ok
If the capacitor selection range is ok
Bridge rectifier selection

If no answer, perhaps I should go to another forum to finalize this projects?

Thanks
Nicolas

Offline Hood

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Re: Power Supply Unit
« Reply #51 on: January 13, 2011, 09:49:44 AM »
Transformer should be fine, think toroidals are less noisy but it should be fine.

Capacitor would be best 50v or hiigher with  capacitance of 20,000uF or higher

PIV means Peak Inverse Voltage I would probably go overkill on the rectifier and get the 400/25 one.

Hood

Offline stirling

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Re: Power Supply Unit
« Reply #52 on: January 13, 2011, 10:25:14 AM »
No one can help with my previous post?

I would like to know if the transformer looks ok
If the capacitor selection range is ok
Bridge rectifier selection

If no answer, perhaps I should go to another forum to finalize this projects?

Thanks


Kolias - I'm going to put my mod hat on just for a second. Your last post is unfair to all the very knowlegable people who have spent a lot of time helping you. Whilst people love to help as much as they can it's also up to you to try to do as much as you can for yourself. Your first two questions have been answered several times by several people and your third... I just typed PIV Bridge Rectifier into google and I got over 7000 results with the 1st on the list telling me all I could ever want to know.

You are of course free to go to any other forum if you think this one isn't good enough but I doubt VERY much that you'll receive as much help and patience as you have here.

mod hat back off  :)

Offline kolias

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Re: Power Supply Unit
« Reply #53 on: January 13, 2011, 11:20:57 AM »
ok so we now have settled all the major components:
The transformer as posted before, capacitor 50V or higher & 20000uf or higher, rectifier 400/25
Tonight I will try to post a schematic for comments and then I will proceed with purchasing.
A BIG thanks to all involved here

Stirling regarding your comments I guess you got me wrong. At the beginning of this post Hood, who has been the only one providing most of the answers, had mentioned:

Yes you will get help here I am sure, I am no electrical whiz but its straight forward enough, must be I managed ::) But there are lots of guys here that are experts so you will be sure to get answers.

Hood

Therefore when I received no answers I thought Hood was waiting for others to reply and when there was no reply from others I thought perhaps I should go elsewhere to get my answers. I must say the intention was NOT to insult anyone or this forum but only to get more help and get going with this project.

I love this forum and all people and it has been a great help on this project and for Mach3

As for the Google search, I try not to use it a lot regarding electrical because I’m really green with this staff. Reading something on Google depends on my interpretation and since I know nothing I may interpret it wrongly and this I don’t want since the consequences can be disastrous.

AGAIN, asking to go to other forum was NOT to insult anyone but rather to help

Nicolas

Offline kolias

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Re: Power Supply Unit
« Reply #54 on: January 13, 2011, 06:23:41 PM »
Here is my schematic and all comments will be appreciated.

I have already made a control station box (1/4” plywood, 20”x 18”x 12” high) which is intended to house the drivers and BOB and there is space to build the power supply unit inside this box. As you can see on my schematic I connect the ground from the AC supply to a ground metal bar and in the same bar I connect the black wire from the DC. I dont know if this is correct.

The other point I’m not sure is the size of the fuses; I have 10A fuse for the AC and DC but not sure if this is sufficient.
Nicolas

Offline RICH

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Re: Power Supply Unit
« Reply #55 on: January 13, 2011, 06:45:41 PM »
Quote
control station box (1/4” plywood)

Strongly suggest a metal enclose.

RICH

Offline kolias

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Re: Power Supply Unit
« Reply #56 on: January 13, 2011, 07:38:24 PM »

Strongly suggest a metal enclose.

RICH


A couple years ago when I built my old CNC, I had asked a friend about the control box and he suggested against a metal enclosure to avoid the possibility of sort circuit between wires touching the metal enclose.

Can I ask why a metal enclosure is suggested ?
Nicolas

Offline ger21

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Re: Power Supply Unit
« Reply #57 on: January 13, 2011, 08:10:38 PM »
I don't know much about electronics, but I know that you shouldn't have a fuse in your AC ground wire. The fuse defeats the purpose of the ground.
Gerry

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Offline RICH

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Re: Power Supply Unit
« Reply #58 on: January 13, 2011, 08:39:42 PM »
Quote
Can I ask why a metal enclosure is suggested ?

Metal is not combustable and will contain a spark,fire, smoke,  and to some degree an explosion.

The metal enclosure acts as a shield thus preventing  transmitting and recieving spurious signals.

The metal enclosure allows for grounding. Should a wire break and touch the box , the box is grounded / it is bonded to the ground wire and such provides a less resistive path to ground. You could think of this as the same reason for having a ground wire run along with the other wires in a shield.

The box is basicaly a junction box and code may require you to put it in a metal enclosure.

Not to argue with your friends advice but I disagree with your friends advice. (Don't let him do any wiring in your house  ;))

RICH

 
« Last Edit: January 13, 2011, 08:41:58 PM by RICH »

Offline kolias

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Re: Power Supply Unit
« Reply #59 on: January 13, 2011, 08:44:18 PM »
I don't know much about electronics, but I know that you shouldn't have a fuse in your AC ground wire. The fuse defeats the purpose of the ground.

Sorry Gerry but my sketch is not clear enough. The fuse is installed on the black wire (Line) of the 120VAC cable.

The ground wire is broken to allow me only to write 10A Fuse
Nicolas