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PCB fuses for 60VDC 75Amps

J

Jamie Morken

Jan 1, 1970
0
Hi,

I am trying to decide the best fuses to use for a battery inverter with
a max voltage of 60VDC and max operating current of 75Amps. The
operating current is limited to 75Amps by the power supply, so the fuse
is just a backup, so I was thinking setting the fuse to 80Amps or even a
bit higher. The 60VDC is higher than most fuses seem to allow, due to
arcing, but there are some 5mm x 20mm ceramic fuses that are rated
16Amps at 125VDC:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=0001.2516-ND

and some 5mm diameter beryllium copper fuse holders:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2827-ND

Would putting 5 of these fuses in parallel work well with a continuous
max operating current of 75Amps?


Also I was thinking of some 3AG fuses (1/4" or 6.35mm diameter), the
glass fuses in this size are rated only to 32VDC, but there are also
some ceramic rated at 30Amps and 125VDC. So three of these in parallel
could work as well.

3AG fuse:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F2655-ND

3AG(1/4") fuse holders:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F046-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2342-ND

Are there any other cheaper ways to fuse 60VDC/75Amps on a PCB that can
meet UL standards? I was thinking of using ATO/ATC series automotive
blade style fuses, but these seem to mainly be rated to only 32VDC.

ATC series 30Amp/32VDC fuse:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2322-ND

ATC series fuseholders:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3522K-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3522-2K-ND

I'd like to just pop in 3 of those ATC series fuses, but I don't know if
its really that safe at 60VDC. (might make an arc welder?) Are there
any other higher volt rated blade fuses in these sizes?

cheers,
Jamie
 
L

linnix

Jan 1, 1970
0
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.
 
L

legg

Jan 1, 1970
0
Hi,

I am trying to decide the best fuses to use for a battery inverter with
a max voltage of 60VDC and max operating current of 75Amps. The
operating current is limited to 75Amps by the power supply, so the fuse
is just a backup, so I was thinking setting the fuse to 80Amps or even a
bit higher. The 60VDC is higher than most fuses seem to allow, due to
arcing, but there are some 5mm x 20mm ceramic fuses that are rated
16Amps at 125VDC:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=0001.2516-ND

and some 5mm diameter beryllium copper fuse holders:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2827-ND

Would putting 5 of these fuses in parallel work well with a continuous
max operating current of 75Amps?


Also I was thinking of some 3AG fuses (1/4" or 6.35mm diameter), the
glass fuses in this size are rated only to 32VDC, but there are also
some ceramic rated at 30Amps and 125VDC. So three of these in parallel
could work as well.

3AG fuse:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F2655-ND

3AG(1/4") fuse holders:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F046-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2342-ND

Are there any other cheaper ways to fuse 60VDC/75Amps on a PCB that can
meet UL standards?

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
http://www.littelfuse.com/data/en/Data_Sheets/1575701_Strip_fuses.pdf

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
 
L

legg

Jan 1, 1970
0
Hi,

I am trying to decide the best fuses to use for a battery inverter with
a max voltage of 60VDC and max operating current of 75Amps. The
operating current is limited to 75Amps by the power supply, so the fuse
is just a backup, so I was thinking setting the fuse to 80Amps or even a
bit higher. The 60VDC is higher than most fuses seem to allow, due to
arcing, but there are some 5mm x 20mm ceramic fuses that are rated
16Amps at 125VDC:


Are there any other cheaper ways to fuse 60VDC/75Amps on a PCB that can
meet UL standards?

You might consider PTC's:

http://www.littelfuse.com/data/en/Data_Sheets/Littelfuse_LT.pdf

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

RL
 
S

Spehro Pefhany

Jan 1, 1970
0
Littelfuse has been promising a 55v aqutomotive fuse for some time.

We got a bunch, I think from them, but they are scarcer than the
proverbial hen's teeth.
The 80V strip fuses are still the only non-ceramic kind with a safety
approval attached
http://www.littelfuse.com/data/en/Data_Sheets/1575701_Strip_fuses.pdf

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
Best regards,
Spehro Pefhany
 
T

Tom Bruhns

Jan 1, 1970
0
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.

75A*0.1ohms = 7.5V. 75A^2*0.1ohms = 562W. You might want to re-think
that a bit. And it's still NOT a fuse; it's an electronic circuit
breaker with almost certainly some shortcomings with respect to
fuses. Given that the OP already has electronic protection in the
circuit, I suppose the fuse should be there to take care of those
situations where an electronic breaker can't do the job.

Cheers,
Tom.
 
J

JosephKK

Jan 1, 1970
0
Hi,

I am trying to decide the best fuses to use for a battery inverter with
a max voltage of 60VDC and max operating current of 75Amps. The
operating current is limited to 75Amps by the power supply, so the fuse
is just a backup, so I was thinking setting the fuse to 80Amps or even a
bit higher. The 60VDC is higher than most fuses seem to allow, due to
arcing, but there are some 5mm x 20mm ceramic fuses that are rated
16Amps at 125VDC:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=0001.2516-ND

and some 5mm diameter beryllium copper fuse holders:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2827-ND

Would putting 5 of these fuses in parallel work well with a continuous
max operating current of 75Amps?


Also I was thinking of some 3AG fuses (1/4" or 6.35mm diameter), the
glass fuses in this size are rated only to 32VDC, but there are also
some ceramic rated at 30Amps and 125VDC. So three of these in parallel
could work as well.

3AG fuse:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F2655-ND

3AG(1/4") fuse holders:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F046-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2342-ND

Are there any other cheaper ways to fuse 60VDC/75Amps on a PCB that can
meet UL standards? I was thinking of using ATO/ATC series automotive
blade style fuses, but these seem to mainly be rated to only 32VDC.

ATC series 30Amp/32VDC fuse:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2322-ND

ATC series fuseholders:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3522K-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3522-2K-ND

I'd like to just pop in 3 of those ATC series fuses, but I don't know if
its really that safe at 60VDC. (might make an arc welder?) Are there
any other higher volt rated blade fuses in these sizes?

cheers,
Jamie
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.
 
Q

qrk

Jan 1, 1970
0
Hi,

I am trying to decide the best fuses to use for a battery inverter with
a max voltage of 60VDC and max operating current of 75Amps. The
operating current is limited to 75Amps by the power supply, so the fuse
is just a backup, so I was thinking setting the fuse to 80Amps or even a
bit higher. The 60VDC is higher than most fuses seem to allow, due to
arcing, but there are some 5mm x 20mm ceramic fuses that are rated
16Amps at 125VDC:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=0001.2516-ND

and some 5mm diameter beryllium copper fuse holders:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2827-ND

Would putting 5 of these fuses in parallel work well with a continuous
max operating current of 75Amps?


Also I was thinking of some 3AG fuses (1/4" or 6.35mm diameter), the
glass fuses in this size are rated only to 32VDC, but there are also
some ceramic rated at 30Amps and 125VDC. So three of these in parallel
could work as well.

3AG fuse:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F2655-ND

3AG(1/4") fuse holders:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F046-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2342-ND

Are there any other cheaper ways to fuse 60VDC/75Amps on a PCB that can
meet UL standards? I was thinking of using ATO/ATC series automotive
blade style fuses, but these seem to mainly be rated to only 32VDC.

ATC series 30Amp/32VDC fuse:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2322-ND

ATC series fuseholders:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3522K-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3522-2K-ND

I'd like to just pop in 3 of those ATC series fuses, but I don't know if
its really that safe at 60VDC. (might make an arc welder?) Are there
any other higher volt rated blade fuses in these sizes?

cheers,
Jamie

Bussmann's TPS series fuses are PCB mountable, max 70A, work up to
170VDC.
http://www.cooperbussmann.com/pdf/c1bf6ae1-194a-46da-b3a8-6f0557f55061.pdf

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.
 
J

Joerg

Jan 1, 1970
0
Jamie said:
Hi,

I am trying to decide the best fuses to use for a battery inverter with
a max voltage of 60VDC and max operating current of 75Amps. The
operating current is limited to 75Amps by the power supply, so the fuse
is just a backup, so I was thinking setting the fuse to 80Amps or even a
bit higher. The 60VDC is higher than most fuses seem to allow, due to
arcing, but there are some 5mm x 20mm ceramic fuses that are rated
16Amps at 125VDC:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=0001.2516-ND


and some 5mm diameter beryllium copper fuse holders:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2827-ND


Would putting 5 of these fuses in parallel work well with a continuous
max operating current of 75Amps?


Also I was thinking of some 3AG fuses (1/4" or 6.35mm diameter), the
glass fuses in this size are rated only to 32VDC, but there are also
some ceramic rated at 30Amps and 125VDC. So three of these in parallel
could work as well.

3AG fuse:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F2655-ND

3AG(1/4") fuse holders:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=F046-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2342-ND


Are there any other cheaper ways to fuse 60VDC/75Amps on a PCB that can
meet UL standards? I was thinking of using ATO/ATC series automotive
blade style fuses, but these seem to mainly be rated to only 32VDC.

ATC series 30Amp/32VDC fuse:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=283-2322-ND


ATC series fuseholders:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3522K-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3522-2K-ND

I'd like to just pop in 3 of those ATC series fuses, but I don't know if
its really that safe at 60VDC. (might make an arc welder?) Are there
any other higher volt rated blade fuses in these sizes?

Do yourself a favor and get something sturdy, such as these:
http://www.homedepot.com/webapp/wcs...3&productId=100112509&N=10000003+90029+500775

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.
 

neon

Oct 21, 2006
1,325
Joined
Oct 21, 2006
Messages
1,325
Fuses are there to prevent total wipe out as a protection. 80 12a any fuse rating means close but never exact value. It will stop a sustaining short the better the short the better the protection. And to make even things more interesting there are slow blow, fast fuses ,containament fuses and then some more which are you thinking of using hummm?
 
J

Joerg

Jan 1, 1970
0
RST said:
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.

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 ...
 
J

JosephKK

Jan 1, 1970
0
I didn't think the OP would be so stupid as to use bare wire without putting
a teflon/tefzel sleeve over it.

Jim

Do you think that the covering might reduce the interrupting capacity?
 
J

Joerg

Jan 1, 1970
0
RST said:
I didn't think the OP would be so stupid as to use bare wire without putting
a teflon/tefzel sleeve over it.

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.
 
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