Douglas · May 17, 2018 says:
According to Littlefuse, the inventor of the ATO fuse, the idea that ATO
means OPEN and ATC means CLOSED is a myth. When Littlefuse applied for
patent rights for the fuse name, they could not patent AUTO, which they
wanted to do since the fuse is intended for vehicle use. So they
patented the name ATO for Auto.

Littlefuse's competitors obviously could not use the ATO name, so they
came up with ATC. Whether the myth of ATO=open and ATC=closed came from
those competitors is not clear. However, you will find that ATO is still
a trademark for Littlefuse, and ATC uses can be found with both closed
and open bottoms - which pretty much debunks the myth.


So what is an APR fuse?

https://www.optifuse.com/fuses-auto-blade-reg-apr.php but it doesn't
say! Not even it its glossary or selection guide.

https://media.digikey.com/pdf/Data%2...DFs/APR-UL.pdf
It seems to have something to do with how fast the fuse blows, but the
first link describes the whole category as Fast Acting/Blade Mounting.

I think the graph is bragging that they do blow quickly, not saying that
they are in any way slo-blo.

Or maybe they are saying they blow within a range of time, but then how
is that different from ATC or ATO?

On Sat, 08 May 2021 22:27:10 -0400, micky
wrote:



Douglas · May 17, 2018 says:
According to Littlefuse, the inventor of the ATO fuse, the idea that ATO
means OPEN and ATC means CLOSED is a myth. When Littlefuse applied for
patent rights for the fuse name, they could not patent AUTO, which they
wanted to do since the fuse is intended for vehicle use. So they
patented the name ATO for Auto.

Littlefuse's competitors obviously could not use the ATO name, so they
came up with ATC. Whether the myth of ATO=open and ATC=closed came from
those competitors is not clear. However, you will find that ATO is still
a trademark for Littlefuse, and ATC uses can be found with both closed
and open bottoms - which pretty much debunks the myth.


So what is an APR fuse?

https://www.optifuse.com/fuses-auto-blade-reg-apr.php but it doesn't
say! Not even it its glossary or selection guide.

https://media.digikey.com/pdf/Data%2...DFs/APR-UL.pdf
It seems to have something to do with how fast the fuse blows, but the
first link describes the whole category as Fast Acting/Blade Mounting.

I think the graph is bragging that they do blow quickly, not saying that
they are in any way slo-blo.

Or maybe they are saying they blow within a range of time, but then how
is that different from ATC or ATO?

ATC and ATO are just made by different manufacturers but follow the
same standards.

Fuses are generally designated by a 3 character type. This is just the
tip of the iceberg but it will get you started.
There are dozens more types of fuses in just about any amperage you
want.


https://en.wikipedia.org/wiki/Fuse_(automotive)

In alt.home.repair, on Sun, 09 May 2021 10:52:09 -0400,
wrote:

On Sat, 08 May 2021 22:27:10 -0400, micky
wrote:



Douglas · May 17, 2018 says:
According to Littlefuse, the inventor of the ATO fuse, the idea that ATO
means OPEN and ATC means CLOSED is a myth. When Littlefuse applied for
patent rights for the fuse name, they could not patent AUTO, which they
wanted to do since the fuse is intended for vehicle use. So they
patented the name ATO for Auto.

Littlefuse's competitors obviously could not use the ATO name, so they
came up with ATC. Whether the myth of ATO=open and ATC=closed came from
those competitors is not clear. However, you will find that ATO is still
a trademark for Littlefuse, and ATC uses can be found with both closed
and open bottoms - which pretty much debunks the myth.


So what is an APR fuse?

https://www.optifuse.com/fuses-auto-blade-reg-apr.php but it doesn't
say! Not even it its glossary or selection guide.

https://media.digikey.com/pdf/Data%2...DFs/APR-UL.pdf
It seems to have something to do with how fast the fuse blows, but the
first link describes the whole category as Fast Acting/Blade Mounting.

I think the graph is bragging that they do blow quickly, not saying that
they are in any way slo-blo.

Or maybe they are saying they blow within a range of time, but then how
is that different from ATC or ATO?

ATC and ATO are just made by different manufacturers but follow the
same standards.

Yes, ATO was trademarked by Littelfuse, although now Littelfuse might be
moving to ATOF (tin plated) and ATO Ag (silver plated).

https://m.littelfuse.com/~/media/aut..._datasheet.pdf

Fuses are generally designated by a 3 character type. This is just the
tip of the iceberg but it will get you started.

WADR, I was already started. I asked what an APR fuse was.

There are dozens more types of fuses in just about any amperage you
want.


https://en.wikipedia.org/wiki/Fuse_(automotive)

Alas, that page just lists APR fuses along with ATO and ATC, and doesn't
say a word about what makes APR different from others.

"Regular (APR / ATC / ATO / ATS)"

On Sun, 09 May 2021 12:10:43 -0400, micky
wrote:


Alas, that page just lists APR fuses along with ATO and ATC, and doesn't
say a word about what makes APR different from others.


Since your Google seems to be broken, let me help
APR is a generic replacement for ATO / ATC fuses (trade names
registered to Littelfuse / Bussmann respectively).

They all meet the same standard, just different manufacturers.

In article ,
says...

ATC and ATO are just made by different manufacturers but follow the
same standards.




I do have to disagree with you on that. The ATC and ATO are two
different ways of making the blade type car fuses. The ATC is a closed
fuse element so that water can not get in and cause corosion. The ATO
has an opening where the fuse element is and water can get in.

There is an APR fuse that is suppose to be a replacement for both of the
above.

I have not verified it, but I am thinking the is for the blade type
fuses and they are only rated for 32 volts. I may be off on the
voltage, but it is more than 24 and less than 50 volts DC.

On Sun, 9 May 2021 15:41:24 -0400, Ralph Mowery
wrote:

In article ,
says...

ATC and ATO are just made by different manufacturers but follow the
same standards.




I do have to disagree with you on that. The ATC and ATO are two
different ways of making the blade type car fuses. The ATC is a closed
fuse element so that water can not get in and cause corosion. The ATO
has an opening where the fuse element is and water can get in.

NOT true. It is branding only. Littlefuse vs Bussman
ATO was available for registering - Auto was not - so Littlefuse
registered ATO as it's "auto" fuse. When Cooper Industries Bussman
division got into the market they used ATC for AT style COOPER.

There is an APR fuse that is suppose to be a replacement for both of the
above.

I have not verified it, but I am thinking the is for the blade type
fuses and they are only rated for 32 volts. I may be off on the
voltage, but it is more than 24 and less than 50 volts DC.

32 volts for 24 volt vehicular electical systems
Also APS, APM, APR and APX Automotive Protection Small, Automotive
Protection Mini, Automotive Protection Regular and Automotive
Protection Xtra for small, mini, regular and Maxi.

There is also the theory (unproven to this point) that the AP stands
for Anderson Products - another large Automotive fuse and device
supplier (now Impulse Electronics) - manufacturer of, among other
things, the PowerPole quick disconnect power connector that has
established several "standards" in the low voltage DC sphere.

In article ,
says...

NOT true. It is branding only. Littlefuse vs Bussman
ATO was available for registering - Auto was not - so Littlefuse
registered ATO as it's "auto" fuse. When Cooper Industries Bussman
division got into the market they used ATC for AT style COOPER.




It seems to be acombination of both. One is branding as a trademark by
companies, and there is a difference in the way they are made. One
completely closed in plastic and one with the element exposed to air.
Maybe a paten problem, I don't know.

https://www.fusetaps.com/ato-atc-15a-fuse.html