James Kirk Posted February 19, 2022 Share Posted February 19, 2022 Hello all, I'm looking for a wiring diagram for the alternator to work with a MS2 ECU. I'm not familiar with the operation of these alternator and I haven't found much information about them so I figured I would pry from the experts. Thank you, James Kirk Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 19, 2022 Share Posted February 19, 2022 Megasquirt has nothing to do with the alternator, leave it wired up as it is. 1 Quote Link to comment Share on other sites More sharing options...
James Kirk Posted February 23, 2022 Author Share Posted February 23, 2022 On 2/19/2022 at 2:18 PM, Bowie69 said: Megasquirt has nothing to do with the alternator, leave it wired up as it is. Yes, the MS2 has nothing to do with the alternator but, the engine isn't in a land rover anymore and I'm looking for a wiring diagram that shows which wire is the exciter and I'm assuming that the other wire is a signal wire. I'm building a completely new wiring harness for this tube framed mid-engine buggy with the lighter weight 4.0 assembly. Thank you, James Kirk Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 23, 2022 Share Posted February 23, 2022 So know I'm wondering why you are posting in the MS forum about how to wire up an alt? Should just be totally standard, follow the vehicle wiring diagrams, if you need those then they are likely listed in the tech archive, or just Google them. Quote Link to comment Share on other sites More sharing options...
James Kirk Posted February 23, 2022 Author Share Posted February 23, 2022 25 minutes ago, Bowie69 said: So know I'm wondering why you are posting in the MS forum about how to wire up an alt? Should just be totally standard, follow the vehicle wiring diagrams, if you need those then they are likely listed in the tech archive, or just Google them. I figured the MS guys had encountered this issue before and would be easily advisable. If you are keeping most of the original wiring this issue wouldn't occur. From the vehicle wiring diagrams that I have looked at, they just show what color wire goes where and not what they do, except for ground of course. I will look through the tech archive. Thank you, James Kirk Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 25, 2022 Share Posted February 25, 2022 Usually W is for Winding which is the tacho feed on diesels, the big lug goes to the battery and the remaining small terminal goes to the warning light. Pretty sure on my P38 V8 alternator there's just the big main terminal and the sense (warning light) terminal. Quote Link to comment Share on other sites More sharing options...
James Kirk Posted February 26, 2022 Author Share Posted February 26, 2022 22 hours ago, FridgeFreezer said: Usually W is for Winding which is the tacho feed on diesels, the big lug goes to the battery and the remaining small terminal goes to the warning light. Pretty sure on my P38 V8 alternator there's just the big main terminal and the sense (warning light) terminal. This alternator has three wires, the big lug went into the main breaker box and back to the battery, there is also a white and brown/yellow stripe. I figured one was to excite the alternator (12volt feed) and the other a signal. I'd hate to put power to the wrong terminal. Unfortunately, I lost my 99 Disco 1 in a divorce last year or I would just test for voltage on that one to find out. I don't know anyone with one either, these older Disco's aren't very popular across the pond. I think it is the lack of aftermarket parts here, jeep and toyota have the market cornered. But, neither of them, ride like a rover. Thanks for the reply, James Kirk Quote Link to comment Share on other sites More sharing options...
Escape Posted February 26, 2022 Share Posted February 26, 2022 Brown/yellow is for the warning lamp, goes to terminal D, white (or white green) is for the tacho, goes to terminal W. Quote Link to comment Share on other sites More sharing options...
James Kirk Posted February 26, 2022 Author Share Posted February 26, 2022 11 hours ago, Escape said: Brown/yellow is for the warning lamp, goes to terminal D, white (or white green) is for the tacho, goes to terminal W. Thank you. So, this is a one wire alternator with two additional outputs, no additional exciting needed to start the alternator it pulls 12volt off the main wire to initiate power generation. James Kirk Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 26, 2022 Share Posted February 26, 2022 No, the warning lamp does the excitation, just like any other vehicle alternator. Quote Link to comment Share on other sites More sharing options...
Escape Posted February 26, 2022 Share Posted February 26, 2022 1 hour ago, James Kirk said: Thank you. So, this is a one wire alternator with two additional outputs, no additional exciting needed to start the alternator it pulls 12volt off the main wire to initiate power generation. James Kirk If the alternator were to pull 12V off the main, permanently live feed wire, the windings would always be powered and thus drain the battery. 😉 All alternators are however capable to self excite to some level, usually this requires higher revs but some are designed to start charging as soon as they turn, even without an additional input. As those are (still) the exception, I think the technology is either to expensive or not reliable enough (or both). Quote Link to comment Share on other sites More sharing options...
James Kirk Posted February 27, 2022 Author Share Posted February 27, 2022 1 hour ago, Escape said: If the alternator were to pull 12V off the main, permanently live feed wire, the windings would always be powered and thus drain the battery. 😉 All alternators are however capable to self excite to some level, usually this requires higher revs but some are designed to start charging as soon as they turn, even without an additional input. As those are (still) the exception, I think the technology is either to expensive or not reliable enough (or both). I've heard of one-wire alternators. Yes, you are correct at higher rpms excitation isn't necessary. Well at least it's not at the hydro-electric power plants that I work at, excitation is only needed at startup according to the electricians that work here. I'm more mechanical but, I'm learning electricity, it's shocking! Thank you, Bowie69 wrote the exciting wire, James Kirk Quote Link to comment Share on other sites More sharing options...
James Kirk Posted February 27, 2022 Author Share Posted February 27, 2022 3 hours ago, Bowie69 said: No, the warning lamp does the excitation, just like any other vehicle alternator. Thank you for the information. James Kirk Quote Link to comment Share on other sites More sharing options...
James Kirk Posted February 27, 2022 Author Share Posted February 27, 2022 The first picture was from a few years back when I moved into my house, it is a little different. I have been designing/machining the parts for the independent suspension, transfer cases and planetary hubs that still aren't finished. The second picture is after I mocked up the front differential. It's been challenging and fun. I probably need to take more pictures as I complete steps. 2 Quote Link to comment Share on other sites More sharing options...
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