45 amps on a circuit board?

it just seems like a bad idea to me....

Hi Del,

You say that, cuz you may have not ever had the opportune to do it. It does work if done right = read my thread.

I'm not sure why you would want to, PCB's are for electronics, not power distribution. But hey, lay one down and see what happens. I expect that even if the board survives, how are you going to shield a 45 amp conductor on a PCB?

I've done it. No problem. My last power supply board carried 60 amps - and I still have all my fingers. 4 layers of 4 oz is overkill - well, it really depends on your cross section. Google up some specs on power dissipation and temperature rise in PCBs - that's your limiting factor. I think I used something like 3 inch wide traces of 2 oz copper.

The real trick is getting the current on and off the board.

We were using a Phoenix 1714968

I just noticed it's max current is 32 amps. Guess I'll need to get with my engineer.

I'll have to see if there is a connector for more amps.

Or use multiple connectors. You're not going to want to put 45 amps through a single wire anyway, unless you use something like 10AWG wire - and that's pretty unwieldy.

Hi meckert,

Just make sure the total cross-sectional area and the length of the copper traces can handle that much current.

Simple.

Mike

I can't help with the science, but there are many audio amplifier solutions delivering 10,000 watts into 4 ohm loads ... no kidding ... its real.

On the loudspeaker side, we've tested dual 2-ohm drivers at nearly 10,000 watts in tone-burst conditions for DAYS without failure ... two amplifiers (Crown Macrotech 5002V2 in parallel-mono), about 100 volts into a 2-load = about 50 amps per amplifier.

"Who does that?" you ask. Car aftermarket ... all those kids in the neighborhood you hate ... boom, boom, boom from 3 blocks away ... my fault .

Also, just so you won't think its just the 'kids', there are pro and commercial amplifier solutions that deliver 10k watts in a 1U rack space. I have no idea how they do that, but that's real also.

Sorry I'm not answering your specific question, but, it's being done.

You can do it either with wide strips of copper or copper "rails" above the PCB (but I think wide strips can be sufficient)

When you talk about DC or very slow AC - no problem, it depends just on the width of traces determined by space and by temperature rise of the PCB determined by your ambient temperature conditions.

If you have higher frequencies as you get with fast switching operations it may become problematic as your pulse shapes wil round and you get more and more losses.
Regards Uwe

I concur with several others: And where 35A+ 220VAC 50/60Hz was the application and a power distribution PCB. Because of constraints, to include safety, only one plating run on the bottom side was done using 3-oz copper and a maximum width for each paying attention to spacing. In later revision, I placed a solder mask on each of these plating runs as to add the additional solder. It works well and should work just fine at 45 amps. I used Phoenix Contact wire-to-pcb connectors and P&B 30A pcb relays. The only issues were if the #10AWG wires were not properly tightened and the PCB (and connector) would be damaged. That's an assembly issue in itself. All of this was applied over a mfr'ing arena for some 10 years. It should work for you.

Thanks for all the great responses everyone!