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TR2/3/3A Is a 25 AGC fuse equivalent to an original 30 amp fuse?

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K

karls59tr

Obi Wan
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I recently went on a drive and the car went dead. I have an electric fuel pump. Turned the key on and could not here the usual hum the pump makes. Checked the fuse and it looked ok but no power to one side of the fuse! Installed a new fuse and I was back on the road. Why would the metai strip inside the "blown" fuse still look intact?
 
CJD said:
Good question...can you post a pic?
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100_2357.JPG
 
Not unknown for the cap on a fuse to become disconnected from the inside strip. Ohm it and check. And as Bob notes, it could also be that the contact at one or the other of the "prongs" of the fuse holder become a bit corroded and lose contact. A piece of a "green" ScotchBrite pad in the glovebox can be valuable in that case. šŸ˜‰
 
DrEntropy said:
Not unknown for the cap on a fuse to become disconnected from the inside strip. Ohm it and check. And as Bob notes, it could also be that the contact at one or the other of the "prongs" of the fuse holder become a bit corroded and lose contact. A piece of a "green" ScotchBrite pad in the glovebox can be valuable in that case. šŸ˜‰
Click to expand...
The fuse I thought was blown passed the ohmmeter test so I think the issue is with the corroded prongs so I'll try the scotchbrite pad. The lower prong dosn't seem quite secure enough. I'm wondering if it just needs to be bent in a bit? Do you think it's possible for the fuse to get jolted outward just far enough to break the electrical current? Also is the 25AGC fuse equal to the stock 30 amp fuse?
 
Those old-fashioned cylindrical cartridge fuses are famous for that kind of failure. I've seen it many times, as they are used in all kinds of electronic test equipment from that era, and even up to today.

On a quick perusal, the article linked above looks pretty good to me. Also a bit more briefly at the beginning of this page: > Electrical Modifications for a Bugeye Sprite <
 
I had a similar looking blown fuse. The central metal strip looked good, but one of the end caps would spin around. Any ohm meter test was weak and intermittent. The best indicator was that none of the electrics fed by that fuse worked.
 
Sarastro said:
Those old-fashioned cylindrical cartridge fuses are famous for that kind of failure. I've seen it many times, as they are used in all kinds of electronic test equipment from that era, and even up to today.
Click to expand...
So very true. We had a close proximity lightning strike a couple weeks ago, neighbor's new whizz-bang digitally controlled refrigerator was knocked out. Two controller boards, one with the power supply. Two smaller glass tube fuses, they brought them over for me to ohm. Both blown... a trip to the hardware store and the fridge was back up and running.
 
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