AFS 70 Alternator Filter Surge protector- keep or rip out

[jssailem]

I'm planning the refit of my electrical systems. In looking at the lines form the alternator I find the positive lead runs from the alternator to the subject part - an alternator filter.



The alternator for my Perkins 4107 diesel is a "DelcoRemy". Looks like a truck alternator. Best guess is it is a regulated alternator and from the late 70's. The wires to the filter appear 10awg. Filter has connections - Batt - Grnd - Alt.

When I examine the recommended wiring designs for Alternator/Battery charging systems this appears to be an unneeded part.
Not needed remove? Or Keep it?

 

[Mark Maulden]

Two things: 1) the AFS 70 and 2) the "thing" on the bulkhead. The black thing on the bulkhead most definately looks like a transformer. We all know transformers do not work with DC (as a transformer). So, if this is actually hooked up to your alternator, they have to be using the windings as a series inductor as part of a "filter". This looks very homemade...The reason for having a ground (if that is truly where it goes) would be to have a capacitor between power and ground. But the length of the ground wire is probably long and small enough to negate any effects a capacitor would have. It would be interesting to discharge the battery and start it up and see how hot that transformer gets. So, in short, you could keep the AFS70 as its a commercially designed part. You could also bypass it and turn on electronics and see if they still work as intended. Most importantly, listen to the radio un squelched. Also stereo. I would dfinately get rid of the "thing" on the bulkhead. Rewire with correct wire size. If my suspicions are true, and if that thing fails, you could blow the diodes in the alternator. Second thought...Maybe that surge suppressor is there in case that happens?? Who knows what POs think.....

 

[Ron20324]

Trace the wires. Start a wiring schematic.

 

[LloydB]

We all know transformers do not work with DC (as a transformer). So, if this is actually hooked up to your alternator, they have to be using the windings as a series inductor as part of a "filter".
looks like an diy assembled ac/dc power supply to me. if alt regulated voltage was 38 VDC you would want to step it down to 6 VDC to charge your 6 volt batt. My point is that it's best to measure the voltages before you start making a new circuit.
Of course a smoke test can always help indicate a problem ; )