Starter Fuse Pop Problem

f1rocket · #1 04-10-2006, 01:05 PM

I wired my starter circuit ala Bob Nuchols' suggestion. That is to say I have an 18 gauge wire from my starter toggle switch to the starter solenoid. That circuit keeps popping the 7.5 AMP fuse. It usually happens after the engine starts and I then find out about it the next time I go flying. This has happened twice now.

I'm really sure that the wire has continuity between the switch and the solenoid and that it's not chaffed or broken. I just thinking that this curcuit is drawing more amps than anticipated.

Anyone else have any experience with this type of problem?

gmcjetpilot · #2 04-10-2006, 01:41 PM

I agree its pulling more amps. Bob says about 3 amps? I guess you should look at the relay. If there is a make and model may be you can look the up the specs or throw a multi meter/ampmeter into the cuircut that records peek. I am sure you have the catch diode on it. Could the CB be out of spec. Good luck G

f1rocket · #3 04-10-2006, 04:54 PM

It's the standard starter contactor from Van's and yes, I have the diode installed. I'm using fuses rather than circuit breakers.

gmcjetpilot · #4 04-10-2006, 05:51 PM

Quote:

Originally Posted by f1rocket

It's the standard starter contactor from Van's and yes, I have the diode installed. I'm using fuses rather than circuit breakers.

I have a brand new Van's starter relay laying around. I tested it and saw about 3.5 to 3.6 amps steady state (that is with no current going thru the main contactor). It is too fast to read but thought I saw 3.9 to 4.0 amps peek.

I would think a 7 to 8 amp fuse would do. Not sure if they make a slow blow version of the ATC style fuse I assume you are using, but that would be worth a try. Next would be to measure the coil resistance. Mine was about 4.0 - 4.2 ohms (which checks). If the coil resistance is less than 4.0 ohms I would suspect the relay.

George

f1rocket · #5 04-11-2006, 06:17 AM

Thanks George. I'll check it out next time I have the boot cowl off.

az_gila · #6 04-11-2006, 08:26 AM

Randy,

Have you checked the diode with a meter to see if it's still a one-way device?

It's suspicious that it only blows when you release the starter button (switch?)

gil in Tucson