PCB fuses for 60VDC 75Amps

Almost certainly, the parallel combination will unzip at a lower current than the sum of the fusing currents of the individual fuses. This is because the fuses and their holders have a very low minimum resistance, so tiny variations in contact and other resistance can detour more than the expected fraction of the total current to one of the fuses. Once that one blows, there is a cascade of the remaining ones going out. The point is that equal current sharing between parallel fuses is problematic.

There are so called "semiconductor fuses" designed to be put in the DC power buses of SCR and IGBT drive and inverter buses. They have high DC ratings and fast response to over current, compared to normal AC fuses. Many have bolt connections for cables. Butt they are quite spendy.

You can build one with a small power resistor, current sensing op-amp and power transistor. A 10Watts 0.1ohm resistor would be a good starting point.

Littelfuse has been promising a 55v aqutomotive fuse for some time. The 80V strip fuses are still the only non-ceramic kind with a safety approval attached

The breaking energy of these parts, and their terminal shape, will prohibit the use of solder-omly mounting methods - has to be a screw and bolt.

The 156-5611 style is tempting to try as wave-solderable, but it doesn't come with 55v or 80v paperwork - so the approvals process is extremely hairy.

The ATC parts can fly in 24v automotive, as wave-solderable, but 48v and 60v systems are still an expensive proposition for passive protection.

RL

You might consider PTC's:

Not exactly the same as a fuse, but solderable and safety-documented for UL and CE.

RL

We got a bunch, I think from them, but they are scarcer than the proverbial hen's teeth.

Best regards, Spehro Pefhany

There are Telecom fuses that meet that spec, but they may cost a fair bit more than you'd prefer:

Nice interrupting capacity! (1E5 amperes).

Best regards, Spehro Pefhany

Cheers, Tom.

A loop of #28 wire with a small notch filed into the middle of it?

Jim

My error. Too late at night for the fingers to be nimble. That should be #18, fusing current 85 amps or so. The notch should bring it down a bit.

Jim

-- "It is the mark of an educated mind to be able to entertain a thought without accepting it." --Aristotle

As far as i know, and i do not think i am ignorant here, there is no possible PCB mounted fuse that will meet code. 60V & 75 A(dc) is not child's play. Most of the stuff i see advertised for levels like this are 1/2 inch diameter and 1.5 inch long or longer. Good luck.

That is actually pretty standard in that class.

Bussmann's TPS series fuses are PCB mountable, max 70A, work up to

I've used them on 100VDC supplies. In my tests, they cleared in a few milliseconds running a few thousand amps thru them. I was hoping for something more dramatic, but the copper shorting block barely got nicked.

-- Mark

Ouch. $438 for 10 from Digikey.

Best regards, Spehro Pefhany

Do yourself a favor and get something sturdy, such as these:

The currents you are talking about are nothing to sneeze at in terms of the health and property damage they can do if a kludged concoction of cheap fuses blows up.

Then uncle Leroy tosses the morning paper on there. Right behind it is the old curtain, and the fuse decides that it's about time ...

I didn't think the OP would be so stupid as to use bare wire without putting a teflon/tefzel sleeve over it.

Jim

-- "It is the mark of an educated mind to be able to entertain a thought without accepting it." --Aristotle

Professional grade fuses have a lot more than a little sleeve. A sturdy body, sand, etc. Then they test the dickens out of the design to make sure that any somewhat usual kind of blowing happens in a graceful manner and not by sparks flying out of a bursting sleeve.

Robert