[TR] Ruining rheostats

[Ann and Tim Buja]

John Mitchell <jmitch at snet.net> wrote:

> I used a 10 amp acg for the inline which
> should go before the 35 amp Lucas.   John Mitchell  76 TR6

This should be about the right size.  Remember, Lucas and AGC fuses are
rated in different methods:

The number usually found on Lucas fuses is the continuous fusing current
which is twice the continuous amp rating that the system should be using.
The Lucas "35A" fuse will carry 17.5 amps continuously and is supposed to
blow at 35 amps continuous and 40 amps instantaneous.  This is an IEC
standard.

3AG fuses are rated to a UL/CSA standard.
>From the Bussman catalog:
3AG ELECTRICAL CHARACTERISTICS:
% of Ampere	Ampere 	Opening
Rating 	Rating 	Time
110% 		1/32-35	4 hours, Minimum
135%		1/32-35	1 hour, Maximum
200%		1/32-10	5 sec., Maximum
		12-30		10 sec., Maximum
		35		20 sec., Maximum

>From the chart, the 10 AGC fuse will take 4 hours to blow at 11 amps, 1 hour
at 13.5 amps, and five seconds at 20 amps.  This should give you good fuse
coordination with the 35A Lucas fuse rated for 17.5 amps that is controlling
the circuit.

Tim Buja - Rockford, IL - 80 TR8, 73 Stag, 72 TR6