Searching for fuses

[[email protected]]

I'm looking for a source for some fuses for my 1972 ASW 15 panel. They may be called mini barrel fuses and were apparently used in military helicopters. They look like this: http://www.ebay.com/itm/Buss-mini-barrel-fuse-FM01A125V2-10A-military-aircraft-plug-in-cartridge-new-/380757967876?hash=item58a6f18404.

The seller doesn't have the size I need. Thanks.

[Dave Nadler]

On Monday, August 24, 2015 at 11:44:31 AM UTC-4, wrote:
> I'm looking for a source for some fuses for my 1972 ASW 15 panel. They may be called mini barrel fuses and were apparently used in military helicopters. They look like this: http://www.ebay.com/itm/Buss-mini-barrel-fuse-FM01A125V2-10A-military-aircraft-plug-in-cartridge-new-/380757967876?hash=item58a6f18404.
>
> The seller doesn't have the size I need. Thanks.

Try this:
http://www.findchips.com/search/FM09

Hope that helps,
Best Regards, Dave

[Dave Nadler]

PS: This might be a good time to replace your fusing with current
automotive style blade fuses - they are MUCH more reliable!
Stay away from glass cylinder types...

[[email protected]]

Thanks. I found what I was looking for at Digikey. The type of fuse is GMW series. $10 for one fuse. I'll ask my A&P about updating but there are already nice little holes in the panel for the old fuses. Maybe time for a whole new panel! Funny how the need for one fuse can transform into thousands of dollars.

[Surge]

On Monday, 24 August 2015 20:10:07 UTC+2, Dave Nadler wrote:
> PS: This might be a good time to replace your fusing with current
> automotive style blade fuses - they are MUCH more reliable!

I can second that.
Thanks to the recommendations on RAS I'm rewiring my old glider and using blade fuses. Cartridge fuse holders are not very reliable especially if they are mounted on wires that are moved/bumped around a lot.
Blade fuses are cheap, reliable and can be found at any electronics store, fuel/gas station or motor spares stores.

From what I've seen in older gliders the trend appeared to be a main fuse at the battery (or batteries) and one or two main instrument fuses mounted in the instrument panel (usually of the cartridge type). I'm not sure if this was done by the manufacturer or installed later by glider owners but I think it is a very silly set up.
If there is a short circuit in one of the instruments or related circuits, you lose all your instrumentation when the main fuse in the panel blows and you're unlikely going to be able to rectify the short circuit in flight so replacing the fuse will most likely just result in more blown fuses.
The same logic applies to resettable fuses.

Rather fuse each instrument separately according to manufacturer specifications so that if an instrument or related circuit develops a short you only lose that portion of the circuit instead of everything.
I've moved all the instrument fuses (eight of them) behind the instrument panel into a fuse block holder to save panel space and remove the temptation to fiddle when my attention should be outside the cockpit.

10 or 15 Amp fuses right at the battery terminals
14 gauge wire from the batteries to the panel (bit of an overkill)
1,2,3 or 5 Amp fuses for each instrument according to manufacturer recommendations

[[email protected]]

The current fuses are not the glass tube cartridge type. As they were used in helicopters and are mil spec so I would hope that they are fairly reliable. The one I am replacing wasn't blown but damaged - likely by me while trouble shooting a faulty radio. In any case, I do have a blade type at the battery and one fuse for each instrument. Now, when I add an ADS-B box, transponder, PowerFlarm and air conditioning I will probably re-wire. ;>).

[Dave Nadler]

On Monday, August 24, 2015 at 3:03:11 PM UTC-4, wrote:
> Thanks. I found what I was looking for at Digikey.

Yes, much better:
http://www.digikey.com/product-search/en/circuit-protection/fuses/655421?k=fuse%20gmw
Above should have been FM01; DigiKey doesn't list them that way though.

> The type of fuse is GMW series. $10 for one fuse.

That's what happens with old uncommon parts!

> I'll ask my A&P about updating but there are already nice little holes
> in the panel for the old fuses.
> Maybe time for a whole new panel!
> Funny how the need for one fuse can transform into thousands of dollars.

[Ross[_3_]]

Any reason why you are not using circuit breakers?
Fuses seem a little old fashioned these days.

[[email protected]]

Its what came with the ship when I bought it. If it ain't broke....

[John Carlyle]

On Tuesday, August 25, 2015 at 10:55:12 AM UTC-4, Ross wrote:
> Any reason why you are not using circuit breakers?
> Fuses seem a little old fashioned these days.

Circuit breakers waste energy, fuses don't. In a battery powered system blade fuses are the best choice.

-John, Q3

[JS]

Agree with YO, Surge and Q3. Most circuit breakers have a voltage drop.
My recommendation is:
http://www.powerwerx.com/powerpole-power-distribution/rigrunner-4005.html
Or 4008 if you want more circuits.
It'll be tidy and inside the panel. You can't replace a fuse in flight but probably shouldn't.
A side benefit of using 15A PowerPoles for everything is that you can connect any instrument to a battery on the bench if necessary.
Jim

[[email protected]]

On Monday, August 24, 2015 at 10:44:31 AM UTC-5, wrote:
> I'm looking for a source for some fuses for my 1972 ASW 15 panel. They may be called mini barrel fuses and were apparently used in military helicopters. They look like this: http://www.ebay.com/itm/Buss-mini-barrel-fuse-FM01A125V2-10A-military-aircraft-plug-in-cartridge-new-/380757967876?hash=item58a6f18404.
>
> The seller doesn't have the size I need. Thanks.

Re wire the panel, change the to a pull out style CB, save your self the headach

[Charlie M. (UH & 002 owner/pilot)]

On Tuesday, August 25, 2015 at 2:38:23 AM UTC-4, Surge wrote:
> On Monday, 24 August 2015 20:10:07 UTC+2, Dave Nadler wrote:
> > PS: This might be a good time to replace your fusing with current
> > automotive style blade fuses - they are MUCH more reliable!
>
> I can second that.
> Thanks to the recommendations on RAS I'm rewiring my old glider and using blade fuses. Cartridge fuse holders are not very reliable especially if they are mounted on wires that are moved/bumped around a lot.
> Blade fuses are cheap, reliable and can be found at any electronics store, fuel/gas station or motor spares stores.
>
> From what I've seen in older gliders the trend appeared to be a main fuse at the battery (or batteries) and one or two main instrument fuses mounted in the instrument panel (usually of the cartridge type). I'm not sure if this was done by the manufacturer or installed later by glider owners but I think it is a very silly set up.
> If there is a short circuit in one of the instruments or related circuits, you lose all your instrumentation when the main fuse in the panel blows and you're unlikely going to be able to rectify the short circuit in flight so replacing the fuse will most likely just result in more blown fuses.
> The same logic applies to resettable fuses.
>
> Rather fuse each instrument separately according to manufacturer specifications so that if an instrument or related circuit develops a short you only lose that portion of the circuit instead of everything.
> I've moved all the instrument fuses (eight of them) behind the instrument panel into a fuse block holder to save panel space and remove the temptation to fiddle when my attention should be outside the cockpit.
>
> 10 or 15 Amp fuses right at the battery terminals
> 14 gauge wire from the batteries to the panel (bit of an overkill)
> 1,2,3 or 5 Amp fuses for each instrument according to manufacturer recommendations

Sorta agree..... fuses/breakers keep the wires from becoming "candles" when overloaded. Then use a smaller fuse/breaker to protect the next thing in line.
Breakers tend to be "slow blow", which usually "lets the smoke out" before tripping but help prevent/limit fires.
Fuses come in many flavors, from "dual element/motor start" (lots of short overload can go through) to "fast blow" types to save sensitive stuff.

Again, fuse/breaker MUST be equal to or lower than the ampacity of the wire carrying power, fuses/breakers can be even lower than the wire ampacity, but MUST NOT be higher than the wire rating.

[krasw]

AFAIK fuses do not "save" any equipment. The purpose of main fuse attached to every battery onboard is to save your ship from electrical fire if wire from battery to instrument panel shorts out. The individual fuses for instruments do not protect them in any way, they simply keep your other instruments operating while faulty one (with assoc. wiring) is automatically cut out of the circuit, *before* tripping the main fuse. If the "smoke comes out" of your radio, for example, it will likely pull several amps from battery. At that moment radio fuse blows and keeps your main fuse still intact, supplying power to other instruments. There is now way to "push" too many amps in the perfectly working radio.

While we are at it, I might consider it questionable to replace fuse or reset breaker during flight. If you trip a breaker when damaged wire starts to short, is the cure really reset breaker to supply more amperes to faulty wire?

[Dave Nadler]

On Tuesday, August 25, 2015 at 11:28:55 AM UTC-4, John Carlyle wrote:
> Circuit breakers waste energy, fuses don't.

Where does the energy to blow the fuse come from?
Why is voltage drop for low-amperage circuit-breakers is worse?
Discuss amongst yourselves...