Electrical Fuse question

pete.v · Jan 23, 2013

concours said:
The factory workshop manual mentions a 35 A main fuse...

I know! What's up with that? I thought I was pushing it with a 30. I was going to go with a 20 but not without a few spare and a couple of thirty's to fall back on.

concours · Jan 23, 2013

Was the original a fast acting or slow-blow fuse?

pete.v · Jan 23, 2013

concours said:
Was the original a fast acting or slow-blow fuse?

It does not say, just says cartridge type and a nylon holder. Whether a 750 , 850 or MKIII, all 35amp fuse.
I wonder with the loss of residual stuff like the assimilater, zener, stock rectifier and what not for a solid state system (podtronics unit, ei and electronic flasher would reduce this amp load requirement? And whether a 130watt, 180watt 200watt or even 3 phase?

Any service bulletins on this?

vuuduu21 · Jan 23, 2013

From the research i did it appears the old lucas fuses needed to be 35 amps for the inrush current, but would blow at some lower sustained current. the US fuses are rated at constant amps. I measured 43 amps inrush for about 1 second before the constant draw settled at less than 5 with all the lights and boyer ignition powered up.

pete.v · Jan 23, 2013

vuuduu21 said:
From the research i did it appears the old lucas fuses needed to be 35 amps for the inrush current, but would blow at some lower sustained current. the US fuses are rated at constant amps. I measured 43 amps inrush for about 1 second before the constant draw settled at less than 5 with all the lights and boyer ignition powered up.

Thanks vuuduu. LAB has explained the differences many time but ......... I be a slow leaner and a fast forgetter.

DogT · Jan 23, 2013

If you can find the old threads about the fuses from L.A.B., the 35A British fuse is kind of like a 17.5A US fuse. I wouldn't put anything more than a 20A 3AG or similar in it. The 20A automotive are about the same.

Dave
69S

bluto · Jan 23, 2013

DogT said:
If you can find the old threads about the fuses from L.A.B., the 35A British fuse is kind of like a 17.5A US fuse. I wouldn't put anything more than a 20A 3AG or similar in it. The 20A automotive are about the same.

Dave
69S

+1....have been using modern 20 amp blade fuses on my bike for the last few years and they have only blown when I've done something dumb while working on it.....

rpatton · Jan 23, 2013

great-ride-fuse-blows-help-t13725.html

rpatton · Jan 23, 2013

This one is more better.

melting-wire-t11111.html?sid=30b9cc160ec7e95b1ae115204dae0c53#p125688

Electrical Fuse question

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