Fuse Wire

I certainly hope not. I'll have to check that, but I think it has some sort of insulator on it. My suspicion knowing the person involved is that it is automotive sourced.

I'm hoping to convince him to keep using 'real' fuses. I need something more than my own, currently untutored, reservations before I can. If it'll work w/o too many problems I need to tutor my reservations. My biggest problem at the moment is lack of information.

I know one of the concerns is the expense of the mounting block. I'm pretty sure I can at least partly deal with that if I can convince him he needs to stick with the ANN's.

Robert

I can buy that. Lets see 150A @ 48V --> 7kW. OK, I'm being convinced, especially since if it's going to blow it'll likely be 2 to 3 times that. Even if it only takes 50mS that a kJ or so.

I've done that before and will do it again, but if I can keep it from happening in the first place I'd prefer it. Hmm, maybe a controlled demonstration.

They appear to be. They are also pretty much the industry standard EV fuse so they are readily available.

Thanks, this is a big help. You've helped crystallize my concerns.

Robert

It is beginning to sound like it might get quite involved. I certainly don't want to see molten metal flying around.

It's beginning to look like that is going to be necessary.

Thanks Robert

They are not blowing frequently.

Not THE critical rating but I still don't want operate beyond the voltage rating.

Nice thought, but at 32V I'm afraid the voltage is too low.

The ANNs and equivalents do seem to be on the high side but I've not seen any cheaper DC fuses in the 150A/48V range. Three manufacturers that I'm aware of Ferraz-Shawmut, Littlefuse and Cooper-Bussman. Any others that anyone knows of? I think maybe that keeping the arc and resulting molten metal contained may be the cause of the price increment.

Thanks Ross

Robert

Do you mean like this stuff?

I've seen that used, and yes, it makes a terrible mess when it fuses, but that can be constrained to a degree with fiberglass spaghetti tubing.

I don't know about the volts rating and stuff, this was in a battery charger at 30, 40, or 50 amps, at usually 24 - 28V. But it sure wouldn't be hard to do some experiments.

Good Luck! Rich

Hello Robert,

Bare fuse wire? Be careful, that can cause a fire. Or worse, if there is any combustible condition. If that goes wrong your client might not be there anymore.

Regards, Joerg

Hello Robert,

At 150 amp an arbitrary insulator may not help. It needs a controlled 'blowing environment' where it won't spew glowing metal around.

There is also a liability concern. If a client of mine wanted to do something that I don't consider safe I'd let them know in writing.

Are those ANN's UL listed? It's been a while but I believe that was a concern at some point, long ago though. If they aren't listed, how about Class-T fuses?

Regards, Joerg

The ANN150 is a 125Vac/80Vdc 150A (2.5kA IR) fast acting industrial fuse link for use in fork lift trucks,marine and aviation use. If these fuses are blowing frequently maybe your client is not using the right fuse for the application? Perhaps he is using a fast acting fuse where a slow acting (ANL150) would be more suitable.

The voltage rating is NOT the critical rating of the fuse since the purpose is essentially low voltage, high current interrupt rating, - which will depend upon the type of load it is protecting. Because these fuses are designed to rupture without spraying molten metal all over the place attempting to replace them with ordinary fuse wire can be problematic depending upon the actual mounting arrangement and proximity to other equipment.

I note that the Bussmann ANN150 sells for around USD23 ea but this price is over-inflated I think. Also, their fuse holder block for the ANN150 would be extremely expensive as well (guess approx USD30 ea).

I would look for a cheaper alternative. For example the equivalent fuse sells for AUD12 ea or AUD9 for 10+ in Australia, but even here the fuse mounting block is expensive at AUD45 ea.

If your client is re-designing for quantity replacement, - such as for battery and alternator protection - and does not specifically require a 'fast acting' fuse, I would look at what Littelfuse call the "mega fuse" which is much lower in cost for both fuse and mounting block.

Littelfuse MEG150 shown here

These are available from SWE-CHECK

see page 38 (mega fuse) and page 131 (mega fuse holder) of the catalogue for price details.

SWE-CHECK currently price the MEG150 at AUD12 (USD9) per 1 or AUD7.35 (USD5.50) per 100 and the fuse holder at AUD14 (USD10.50) ea.

Ross Herbert

I don't know if it's an Arizona-specific kind of failure, but over the years I've seen several automotive fuses fail apparently due to vibration-induced work-hardening, then they crumble.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

You defiantly DO NOT WANT TO OPERATE PAST THE VOLTAGE RATING with dc. DC will make them arc over, and keep them arcing over when they blow if conditions are right - just like a DC welder. Check out the well documented problems associated with the new 42V automotive standard. That said look to see what's available for the new 42V car fuses. The smaller ones I have seen have a little extra piece of plastic between the loop on a standard blade fuse to help arrest the arc. They will be cheap with many amp ratings both small and large if you can find a reasonable supplier.

Yeah, I've seen Littlefuses paper with the fied 32V automotive blade fuses. That's an interesting thought, I've been a little leary of using the 42 V bus fuses only because little fuses seems to be the only supplier and I havn't seen them in use anywhere yet. THe latter may simply be a lack of exposure on my part. I don't want to spec in an orphan. Still it would be worth looking at non-blade fuses designed for the same envoronment. THe blade fuses did meet the required specs when last I looked

Thanks Jeff Robert

At least you didn't use pennies. ;-)

Cheers! Rich

Not in this case. The fuse had separated at the edge, with multiple fragments, none of which looked "fused".

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

As a young engineer many years ago I was commissioning drives on a new plant, in a fairly remote area of South America. Power dip, the fuses for the main air compressor popped and the plant crashed. No spares could be found and nothing similar was around. At the suggestion of one of the locals I checked out the electricians shop in the nearby town, well more village. What possible chance they'd have motor fuses in the megawatt range, but it was our only hope. Anyway, waded through the chickens and kids in the yard, the 'shop' was piled high with every sort of electrical and other junk. The owner was a wily old fellow, god knows what his real business activities were. Anyway, in my halting portuguese I explained the problem. He thought a moment, then dug into a box of junk and came out with an ancient card containing various sizes of lead wire, with fusing currents marked for each one including motor rating, ranging up to well above above our required power. We bought some wire, installed it across the fuse clamps and got the drive away. Lucky it didn't fail again before the proper replacements arrived, I have no idea whether a real fault would have been cleared cleanly. Not good practice, but I got away with it that time....

These are industrial chargers - they don't go in a battery compartment, you bring the battery to it, like on your forklift. :-)

And, if your batteries are outgassing, they're being abused.

Thanks, Rich

Hello Jim,

Sometimes it's the holder. If it loosens after some years of vibration the fuse and the holder become very hot. In a car that once reached the point of the fuse falling out. Old Ford Cortina on a lone dirt road in Scotland. Took me a half hour of walking around to find that fuse in the dirt.

Regards, Joerg

Sorry about that I didn't mean to leave you in the dark. I wasn't meaning to snap at you by the way so apologies if it seemed that way.

That's sort of what I figured. I can always hope though.

Makes sense to me. I've not seen any blade fuses anywhere near that kind of rating in any case. I did see some interesting stuff proposed for 42V bit they were much more substantial. For control circuits though I can see the possibilities.

Robert

He seems to think they should cost no more than a buck or 2 in 1000's.

I missed these guys. Thanks. That's better than the quantity quote I got from my supplier. They did say there price had been bumped by $4-$5 this year but even still that seems out of line. I've got a bit of a lever to go back to them now and a place that looks like I should be able to get a competitive quote from. Even with shipping and currency conversion.

I would hope, but immediate costs weigh heavily on peoples minds. I've now got another stab a pricing though (Thanks) and I'm starting to work through my mind how to demonstrate the risks of fuse wire. Nothing like a visual example.

Robert

On Wed, 11 Jan 2006 02:46:04 GMT in sci.electronics.design, Rich Grise wrote,

That sounds like the very last thing I would want in my battery compartment where there might be hydrogen gas present.