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Discussion Topic:
6V single terminal starter relay work with 12V?
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Flatbob |
04-24-2011 @ 7:35 AM
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When converting to 12V system will the 6V starter relay work? I notice the 6V only has a single terminal where as 12V has two terminals. Was wondering why the 6V has a built in start button & the 12V doesn't?
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supereal |
04-24-2011 @ 7:48 AM
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You will have to replace the solenoid with a 12 volt type. The difference, besides the internals, is that the design is for both grounding and active buttons or key switches. To use on old Fords, connect the battery side of the solenoid to one of the small terminals, and the starter button to the other. In the later vehicles that furnish voltage to the solenoid, one of the small terminals is grounded, with the other to the switch. The large terminals connect as before to the battery and the starter.
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Flatbob |
04-24-2011 @ 8:56 AM
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Super thanks, will be getting new 12V starter relay.
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Flatbob |
04-24-2011 @ 9:22 AM
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Super, I want to start engine on test stand, how do I wire ignition switch (on/off toggle,) coil, two wire alternator and voltage regulator? Will I need inline fuse somewhere?
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supereal |
04-24-2011 @ 9:59 AM
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The diagram for the ignition and starting portions are not difficult to diagram. However, you mention a "two wire alternator" and "regulator". Generally, alternators do not need an external regulator and, instead have an internal circuit for that purpose. Alternators fall into several different types. One is the familiar "one wire" which, as the description says, has only one connection, the output, which is routed to the battery. Others have two or three posts, one for output to the battery, and one or two to control the unit. If there is one, it usually connects to the ignition circuit and "wakes up" the alternator to signal the engine is running, and charging can commence. Another type, with two wires in addition to the output, has a connection that is routed directly back to the battery. This is a "sampling" circuit that tells the alternator what the actual voltage level is at the battery, rather than an arbitrary point in the electrical system. Charging is then adjusted to maintain the battery independent of the load. One of the main faults with the one-wire kind is that it depends on residual magnetism to "excite" the unit enough to commence charging, and generally requires high engine speed to "kick" it on. Flatheads are slow turning, compared to modern cars, and even with a small pulley, often don't come on easily. We sometimes install a circuit connected to the alternator which provides a ground thru a push button switch to "goose" a reluctant alternator, such as those which haven't been run for a long period. We have found that conversion to an alternator, in many cases, doesn't provide any more charging power than a generator in good condition. You can test run your engine without the charging system as long as the battery is charged enough to run the starter. If you do need to include the alternator, you need to establish what type you have. Finally, a charging system of any type should not be fused. If the circuit goes open due to a blown fuse, the voltage will surge and likely damage the generator or alternator, and any components directly connected to them.
This message was edited by supereal on 4-24-11 @ 10:09 AM
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Flatbob |
04-24-2011 @ 10:54 AM
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Thanks Bob, so once the engine goes from test stand and then into the car I will have no need for a voltage regulator; in other words voltage regulator is only required with a generator?
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supereal |
04-24-2011 @ 1:43 PM
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I haven't seen an alternator that needs a separate regulator, but you do need to know which alternator hookup you need of the types I outlined.
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Early46 |
04-24-2011 @ 4:21 PM
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Bob, It really depends on your definition of an alternator. If you define a generator as having brushes and directly creating DC and an alternator as using slip rings and creating AC with the AC being converted to DC by diodes, then I would have to say that there are many cases of external regulators being used with alternators! Take a look at a 65 T'bird wiring diagram as an example. Flatbob - Are you just trying to run your engine on a test stand with 12V or are you going to install the engine into a 12V car??
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supereal |
04-24-2011 @ 6:01 PM
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My definition of an alternator is a device that produces AC, which is converted to DC by a diode trio. I haven't seen an alternator with an external regulator that wasn't a special purpose unit such as used on high demand equipment such as ambulances or fire trucks. I was referring to the usual units such as the common GM type. We did encounter an unusual alternator in a German built Ford. It was actually controlled by the ECM, which monitors the AC waveform, but it was a tough one to diagnose. There are exceptions to every rule, of course, but the "garden variety" alternators almost always have internal regulation, and can't be confused with generators.
This message was edited by supereal on 4-24-11 @ 6:05 PM
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Flatbob |
04-24-2011 @ 8:04 PM
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Yes, my plans are to run 12V system on test stand & then convert my '36 6V system to a 12V negative ground.
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