Need to double check my thinking

[old]

I'm wiring up an alternator on a 1941 Farmall B but since it has a mag there the problem of no ignition switch. So am I thinking right that I will have to wire up a switch to excite the alternator and then when ever the engine is shut down the switch needs to be turned off again. Am I right??
Thanks
By the way theres not going to be any lights etc so I can't rig it that way either. Its a delco alternator but not the normal 10si but one off a new car or truck
Hobby farm

 

[Anonymous-0]

one possibility to think about, use double pole single throw switch, one side to mag and ground , other side to bat. and alt. that way you will kill engine and bat. power with one switch.

 

[old]

That would work if this mag had a shut off like that but its has the cable type shut off so that idea is out. I checked the mag today to see if it was set up only as a cable shut off or if it was set up for a switch or cable and its set up only for the cable
Hobby farm

 

[Duner Wi]

I believe another way would be to use an oil pressure switch teed in by the gauge.

 

[BhB]

If I am reading this right, when the engine turns off the oil pressure drops and the oil pressure switch opens and disconects the alt.
Bill

 

[onefarmer]

I'm with Duner. Add a pressure switch triggered by the oil pressure. That is how my MF265 and 175 both diesels are hooked up factory. The switch powers the fuel guage and the alt. With no batt ign to worry about seems the simplest way.

 

[Anonymous-0]

Actually, the average oil pressure switch [for a light] is OPEN when there is oil pressure--light is off--and CLOSES when there is no oil pressure, hence [oh-bla-dee, oh-bla-dah] the light goes on, warniing you of low/no oil pressure BECAUSE the circuit to ground is closed, not open.

Closed circuit = continuity, open circuit = no continuity.

 

[fixerupper]

Old,the early 1086 has an oil pressure activated switch that turns the digital tach on and off. Any dealer should have one. I don't know how it's rated for load capacity. Jim

 

[steveormary]

old'

I did one with the double pole single throw switch like leroy in ne did. Worked fine for me however it was not on a mag.

steveormary

 

[redjock]

Just finished working on IHTD-9 with 12 volt system. Needed a voltage regulator, took it to gen shop and he mounted a cutout on the generator.very simple and only needed to hookup bat wire to the cutout.I asked him about using altenator and if I needed to install a switch and he said if you use the later GM altenator all you need is the battery wire.

 

[Bob]

Simple.

Use a 2-terminal normally open oil pressure switch that closes at low PSI... the ones I use close @ 4 PSI. Standard Ignition brand, I can look up the part #, if you'd like.

 

[old]

Part number would be nice. I called the auto parts store tonight and they didn't even have a clue as to what I was asking for. But it was after 6pm here so they only let the dumb guys work that late.
Thanks
Hobby farm

 

[dave guest]

Oil pressure switch is a great idea and the most stock appearing hookup I could think of. No need to mess with mag. Should already have grounding switch and single wire.

 

[dave guest]

Oil pressure switch is a great idea and the most stock appearing hookup I could think of. No need to mess with mag. Should already have grounding switch and single wire.

 

[old]

If the mag was the switch type if would be easy but its the cable pull type so no wires to the mag other then spark plug wires
Hobby farm

 

[RodinNS]

Old, it's a fuel pump switch you want. I think they are a 3 prong job. One grounds the oil pressure light and the other two spades are for the fuel pump. No pressure/no pump. You just wire the control for the alt through that switch. I forget the number of the one I used, but it's a pretty generic switch...

Rod