Alternator Or Battery
Primary and Secondary
NO- is normally open, energized to close the contact
I will refer to a fuse as primary or source and secondary as load. So the purpose of a fuse is to protect the wire it is attached to and also the branch circuits -A fuse block is a branch circuit of the main fuse. You never fuse your branch circuit with a fuse that is close to the main fuse. As an example, connecting a 25 amp fuse to the secondary of our 30 amp main fuse could end up blowing both the main 30 amp fuse and the 25 amp branch circuit fuse. In a situation like that, we would use a 30 amp time-delay fuse and a 25 amp fast blow fuse if it was close to 25 amp as what was needed-this is not in our automotive electrical field that I refer to-so just forget I mentioned it.
So in our motorcycle, the primary side of the fuse 30 amp fuse is connected to the battery. The battery also is connected to the start solenoid through the start solenoid NO contact to the starter. We also have a start relay within the relay box.
The secondary side of the 30 amp fuse goes to the Key switch and also to fuse block #1 and to the positive output of the regulator.
This comes up when guys install a new regulator. They think connecting the new regulator output to the battery will make things work better!!
Well, people have left this forum as I can be somewhat anal when explaining things-never intentional but I come across that way.
So I will point a few things out.
Once the motor is running, the stator and regulator are the primary source of DC-anyone that says there is AC in that is partially correct, however, this is high frequency, you need an oscilloscope to see this ripple-it is insignificant!
So the secondary of the 30 amp fuse is the same attachment point as all of the loads and the regulator.
So connecting the new regulator positive to the battery does several things, all power used must now go through the 30 amp fuse, any additional power above and beyond coming from the battery, plus the regulator must also go through the main fuse. The exception is the added connections made by the owner connected directly to the battery.
In addition, the original circuit of the regulator, the positive went to all the loads, one of those loads was the battery, in this case, the regulator in essence is connected to the primary side of the 30 amp fuse in respect to the regulator positive output. By connecting directly to the battery, we increase the voltage across the battery, basically cooking it, plus the 30 amp fuse was never meant to supply all the power for the motorcycle.
So once running, the alternator/regulator is our primary source of DC and the battery is our secondary source.
FYI all those aftermarket connections made at the battery positive, the current flows from the regulator, through the 30 amp main fuse, to the battery, through your wiring, and hopefully a properly sized fuse to your heated grips, your Denali sound bomb compressor, or some such thing.
That is why the MK-2 and newer have auxiliary wiring coming from the regulator output side, having a small gauge wire, because it is much closer to the positive power source, Regulator, than if connected directly to the battery as many of us do.
And doing that isn't a problem-if my compressor for my Denali horn was connected to the output of the regulator, and it " locked rotor" ( normally it draws around 15 to 20 amp), pushing the horn button on a locked rotor situation might kill my ignition--And I would need to scramble and restart or hope I have enough forward movement to bump start on the release of the horn button.