What are the rules or standards for high current tracks?

[HINDI]

high current tracks

I m designing h bridge for a dc motor that will handel more than 40 AMP
when loaded . I've understued from the protel help that there is some thing called "power plane"that is a thick track capper voided in the PCB with a depth.
Is there any rules or standards for this high current tracks .

HINDI@GAWAB.COM

 

[IanP]

Re: high current tracks

I wouldn't advice transmition of currents of this level through PCBs.
Current paths of this magnitude should go through copper wires!

 

[Johnson]

Re: high current tracks

With high oz and parallel trace anf distributed via, but still 40A is too high.

 

[nicleo]

high current tracks

What about those power traces on motherboard? If I'm not mistaken, CPU current can go very high (100A ?)

 

[sinatra]

Re: high current tracks

It is certainly possible to pass 40A in a normal PCB track.
But it will depend on what is acceptable for your application.

For a DC current of 40A you will have the approximate temperature rise for the following track parameters:
W=40mm, t=35um -> T=13 degrees
W=30mm, t=35um -> T=20 degrees
W=30mm, t=70um -> T=7 degrees
W=20mm, t=70um -> T=14 degrees

W=track width
t=track thickness
T=temperature rise for an external track

Provided that your track is not an internal track those values should hold.
Hope it helps.
S.

 

[skywalker]

Re: high current tracks

Hi, 40A is very high current !
If you have an area with 40A, and you have only 1 or 2 internal layers,
connect the 2 layers area with moore metalized holes, best without thermals.
Other important consideration is the 'correct' width of area in planes, for not
rise high temp. °C, in pcb.

If the area in a mulitlayer board are little, you need moore layers and connect all planes with metalized holes. Moore layers because the thickness if internal layers are 0.5 or 1oz.

Another choice, use a double side pcb, but with HIGH Thickness copper 2 or 3oz, with high copper thicknees you need a lower copper areas.

Hope this help, let me know. Best, Skywalker.

 

[btbass]

high current tracks

You can now get alliminium plate that you can etch your circuit onto, it's available from Farnell. Or if you go to a manufacturer of pcb's, they can even do copper based pcb's. This is what you need for your output power module. Screwed down onto your heatsink. With 2 ounce, or 4 ounce copper layer, 40 Amps is no problem. You need a track width of at least 100mil and not to long, but flood as much copper around your track that can fit.
My baby does 45Amps, no problem.
Iv'e seen a board for a fork lift truck motor, on 3mm copper plate, draws 100Amps! Uses 12 Dsquared mosfets in parallel!!!!

 

[HINDI]

Re: CALCULATION & STANDARDS

THANKS FOR ALL , BUT I WANT MR SINATRA TO GUIDE ME TO THE RESOURCES

" EQUATION + GRAPHS +STANDARDS " THAT HIS CALCULATION BASED ON

MR SINATRA , DO YOU HAVE ANY RESOURCE OR WEB ADDRESSES FOR THE

PCB & WIREING STANDARDS MIL-STD-275 & IPC-D-275

THANKS

 

[cesare]

Re: high current tracks

IPC Standards are available on fileman

 

[HINDI]

Re:what is the file man

could you please guide me to the exact address , because i do not know what is the fileman you talk about

thanks

 

[picotube]

high current tracks

The LINK to the site is available at the Left-Top at EDABoard main page.

Or, fyc, here is the link:

**broken link removed**

 

[echo47]

high current tracks

HINDI, get MIL standards such as MIL-STD-275E (cancelled) from here:
**broken link removed**

 

[Git]

Re: high current tracks

Hindi - there is a good online calculator here :-

http://www.desmith.com/NMdS/Electronics/TraceWidth.html

The same web page also gives the formulas it uses.

There's also an Excel spreadsheet you can download here :-

http://www.p-m-services.co.uk/current_calc.htm

Git

 

[HINDI]

Re: high current tracks

HI , THANKS FOR ALL, BUT I'VE RECIEVED AN EMAIL FROM IRF.COM AS AN ANSWER FOR MY Q IT WAS :

IPC-D-275 is a design standard for rigid printed boards and Rigid Printed board assemblies.Now, It is withdrawn and replaced by IPC 2222 & IPC 2221 . You can decide your pcb track according to these standards.

International Rectifier <tac@irf.com>

THANKS

 

[Git]

Re: high current tracks

Yes - and those calculators use IPC as their basis.

Git

 

[flatulent]

Re: high current tracks

There is an economic aspect to this. The cost of PC material to make these high current traces is much more than the cost of ordinary wire that could carry them.

 

[HINDI]

Re: high current tracks

the maximum current that PCB can handel is 100 A.

 

[sigint]

Re: high current tracks

HINDI,

From a purely economocal standpoint that may be a good rule, but boards are designed for, and are in use, that carry 400 amps or more - very expensive but feasible, I've designed a few myself. In the past solid plane layers, (not traces), of 10 Oz. copper (.3 mm) thick have been used, but 5 Oz. and below are more common these days.

SiGiNT

 

[arcaphill]

Re: high current tracks

See it!

 

[rauol]

Re: high current tracks

you can solder a small busbar or a thick tinned wire over the track to increase its capacity. if the qty is large a busbar punced from a copper sheet can also be used