ATX power supply to drive a 12V DC motor?

[Lionel]

Think about it, the one line that will most definitely get loaded is
the one that also just happens to supply the most current, the +5v line.
Undoubtedly the supplies are designed so the load of a motherboard (and
maybe some minor peripheral) is enough so the supply can run. There
is no need for a built in load resistor because the supplies are intended
for a specific appplication, that will be enough of a load.

In practice, the worst outcome I've seen from huge load mismatches on
ATX PSU's is that the unused rail goes to an extreme of of its
regulation range - eg; 6A on the 12V rail might bump the (unused) 5V
rail up to 5.15V, for example, or heavily loading the 5V rail might
drop an unused 12V rail to 11.5V, etc.

 

[MK]

If it has short circuit protection, the manufacturer will tell you so.
It should be in the instruction booklet (if you have that), or possibly
on the sticker on the outside of the case, or google the model number
on the internet. If you can't find anything, assume it's not protected
against overload/short circuit (many of the older models aren't)

The fuse needs to be connected between the +12V output of the PSU and
the rest of your circuit. Suitable fuses can be found in the automotive
parts section of a local store, if you can't get find them in your
favorite electronics supply store.

I'm finding a hard time finding a 3AG 10A slow blow fuse locally, none
of the electronics stores stock it. The auto electrician has no idea
whether a fuse is fast or slow blow. If I choose a fast blow, can there
be a potential for damage to the motor incase of a spike? Which car
fuse is suitable, a glass fuse or those fuse blades (flat fuses with
the plastic end)?

 

[Rich Grise]

I'm finding a hard time finding a 3AG 10A slow blow fuse locally, none of
the electronics stores stock it. The auto electrician has no idea whether
a fuse is fast or slow blow.

If it's a 3AG, it will have a clear glass barrel. Look in there. If
there's one wire element from end to end, it's fast-blow. If it's full
of springs and bimetallic contacts and other arcane machinery, it's
a slow-blow.

It should also be stamped on the end caps - a slow-blow will identify
itself as, for example, 10ASB.

Good Luck!
Rich

 

[MK]

If it's a 3AG, it will have a clear glass barrel. Look in there. If
there's one wire element from end to end, it's fast-blow. If it's full
of springs and bimetallic contacts and other arcane machinery, it's
a slow-blow.

It should also be stamped on the end caps - a slow-blow will identify
itself as, for example, 10ASB.

Good Luck!
Rich

Rich,

Great stuff, thanks for the info.

Regards,

Michael

 

[Michael A. Terrell]

Rich,

Great stuff, thanks for the info.

Regards,

Michael

http://www.bussmann.com/

http://www.littelfuse.com/
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Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida