Fusible link for older cruisers???

[Degnol]

Is there any reason to retrofit a fusible link or some other fuse in the exciter wire? The one that can become a big ol' toaster.
I know the topic of fusible links has come up many times before, but I'm not sure anyone has asked about the older cruisers.

Thanks,
Ed

 

[Degnol]

Ttt

 

[Pin_Head]

What's an "exciter"?

 

[Degnol]

I thought that an alternator, as opposed to a generator, needed power to it to make juice. And I was under the assumption that the wire from the + terminal on the battery to the alternator was referred to as the "exciter" wire. But no matter what the terminology, is that the wire that has the fusible link in it?

I'm just asking if it would be prudent to retrofit an older cruiser with some sort of fused protection on the bigass 10 ga wire that currently is not fused until it gets to the actual fuseblock?

Could it be just a big fuse, or a resettable circuit breaker? What should the amp rating be, like 60 amps?

PinHead, are the one to answer this, sorry if I'm not using the right terminology.


Thanks,
Ed

 

[Pin_Head]

The alternator does have an exciter (field) wire, but it is already fused. It is important that the battery wire (White) have a fusible link. The alternator B+ wire (I call it the battry output or high current wire) does not have a separate fusible link until FJ60s appeared, IIRC. Whether adding one is prudent is your call.

 

[Degnol]

Charlie, I'm talking about a '66 with a 6 block fuse panel. Is the field wire switched? And are you sure it is fused on a cruiser as old as mine?

You do think I should put some sort of circuit protection between the + on the battery and the alternator? Do you think fusible link is the way to go, or would a circuit breaker work?

Thanks for making clear the field/exciter wire.


Ed

 

[CRZRJames]

I'm not sure about the stock Toyota alternator, but a GM 3 wire alternator needs an "exciter" wire to turn it on. The 10 ga wire that goes from the alternator "bat" terminal to the battery should not hava a fusible link. The 10 ga wire that feeds the fuse block needs to be protected by a fusible link. A fusible link is a 6" piece of wire on the battery end of the 10 ga wire which will burn through before doing damage to the rest of the wiring harness.

The fusible link should be sized 2 sizes smaller than the wire that it protects. A 10 ga wire needs a 12 ga fusible link.

On a stock Toyota LC, all of the current from the Alternator goes through the Ammeter on the dash, which is not the greatest system....but that's another discussion.

James

 

[IDave]

Actually, James, the current from the alternator goes to the ignition switch (unfused), and goes back through to the fusebox before it goes to the ammeter, at least in my 71 and earlier vehicles.

 

[CRZRJames]

I-Dave, you're correct, it takes a circuitous path under the dash but bottom line, all the current to charge the battery goes through the ammeter. There has been some discussion on this board about running a charge wire directly from the alternator 'Bat' terminal to the battery and also taking the ammeter out of the circuit.

I put a GM 3 wire alternator on my 74 FJ40, a dual battery system with a splitter. The charge wire from the alternator goes directly to the splitter and magically the splitter knows which battery to charge.

The original question in this post was about fusible links. If anyone is interested in learning more about them, visit this site. http://www.madelectrical.com/index.shtml

This site has tons of valuable information concerning general wiring and re-wiring of hotrods, and the techniques transfer to Landcruisers very well. I bought his GM alternator installation kit a few years ago and it has worked well for me.

Good Luck,

James

 

[Pin_Head]

Charlie, I'm talking about a '66 with a 6 block fuse panel. Is the field wire switched? And are you sure it is fused on a cruiser as old as mine?

You do think I should put some sort of circuit protection between the + on the battery and the alternator? Do you think fusible link is the way to go, or would a circuit breaker work?

Thanks for making clear the field/exciter wire.


Ed

Yes, the field wire comes from the voltage regulator, which is fused and part of the switched ignition circuits. I am not sure of 66 because I don't have a shcematic that old, but most cars back to before alternators came in were wired that way.

You should already have a fusible link at the battery. They go way back too. You don't need a cirsuit breaker because the only way it will ever fail is if you have a catastrophic short circuit.

 

[Degnol]

I have no fusible/fusable link. Where do they go? Where would I find it if I did have one?

Ed

 

[Pin_Head]

The go in line (in series) with the big white wire from the amp meter and the battery + post, usually right at the battery. You can buy them by the ft at NAPA.

 

[Degnol]

I know that the wire is avaiable, but I have nothing in which to put it, does that make sense? That's why I was thinking in terms of a bigass fuse or circuit breaker. What amperage should I be looking at? I have nothing special in the battery(1) or alternator, OEM, presumably 40-45amp? So is that what I should look at amp-wise or should I look at what the 10ga wire can handle or the battery amps?
Between battery and alternator is where I thought it ought to go.

Sorry I have not yet checked the link above....yet.

I was just hoping to copy PH's homework. Lazy Bastid that I am.

Thanks,
Ed

 

[IDave]

This page he posted describes what we do, Ed. Basically, the link is wire gauge plus 4, ie, 14 gauge link for 10 gauge wire.


http://www.madelectrical.com/catalog/fusible-link.shtml