Lawnmower Generator AC to DC sharing common ground / neutral???
Question is general because I am trying understand fundamentals. I will give specifics as to what I am trying to do so you can understand. I am adding a charging system and electric start to an engine that never had one. I replaced the flywheel with one from a different engine and got the stator associated with that flywheel.
The stator I am using has a single lead. I believe this means the other end of the coil is grounded to the engine block through the stator’s mounting bolts.
The output of the stator is AC. When tested, the voltage was reading about 28-32VAC (RMS) at around 3600 RPM.
If the output is ran through a diode for half wave rectification, I was measuring around 14.5VDC across the battery terminals at around 3600 RPM. This sounds great, just use the diode and be done. However, this engine may turn 5500 RPM, instead of 3600 RPM. I want to use a Rectifier/Regulator instead of a simple diode to regulate the charging voltage. Looking at Rectifier / Regulator options, I soon ran into issues wondering how to wire it with only one lead from the stator.
I am using a Honda GX style key-switch box and starter motor. I was told the starter motor is “case grounded” to the engine and uses DC. My stator is also “case grounded” to the engine block for AC. I believe the ignition coil is grounded to the engine block as well (not sure if that is DC as well?)
When I first did testing (using a diode for rectification), I ran a jumper from the neg side of the battery to a bolt on the crankcase. So here I’m sure the engine block is being used as DC ground.
How does the stator being “grounded” to the engine block interact with the battery and DC circuitry also being ground to the engine block?
Trying to find a rectifier/regulator I was told that I couldn’t get it to work properly because I was using the engine block as ground/neutral for both AC and DC. I was told I needed a 2 wire stator so that I could isolate the AC from the rest of the DC system. But even without the Regulator (when just using a diode) wasn’t I already using the engine block for DC ground and AC neutral? Wouldn’t problems have shown themselves there?
I then came across the B&S 5/9 Amp regulated charging systems. These systems use a single wire stator that produces 28-40VAC RMS (28V for the 5A system and 40V for the 9A system) at 3600 RPM. This is very similar to the output of my stator/flywheel combo. This system uses a 2 wire rectifier/regulator. The two wire regulator is mounted to the engine via a bolt through its center. I assume since there is only 1 input lead and only 1 output lead, the R/R is “case grounded” through this mounting bolt. I assume this is using the same point on the block as ground/neutral for AC and DC.
Can anybody explain to me how this Briggs 5/9A regulated system works? Is a common ground for AC and DC even an issue? Is there a concept I am missing? Is there a hidden isolated ground being used somewhere somehow?
Question is general because I am trying understand fundamentals. I will give specifics as to what I am trying to do so you can understand. I am adding a charging system and electric start to an engine that never had one. I replaced the flywheel with one from a different engine and got the stator associated with that flywheel.
The stator I am using has a single lead. I believe this means the other end of the coil is grounded to the engine block through the stator’s mounting bolts.
The output of the stator is AC. When tested, the voltage was reading about 28-32VAC (RMS) at around 3600 RPM.
If the output is ran through a diode for half wave rectification, I was measuring around 14.5VDC across the battery terminals at around 3600 RPM. This sounds great, just use the diode and be done. However, this engine may turn 5500 RPM, instead of 3600 RPM. I want to use a Rectifier/Regulator instead of a simple diode to regulate the charging voltage. Looking at Rectifier / Regulator options, I soon ran into issues wondering how to wire it with only one lead from the stator.
I am using a Honda GX style key-switch box and starter motor. I was told the starter motor is “case grounded” to the engine and uses DC. My stator is also “case grounded” to the engine block for AC. I believe the ignition coil is grounded to the engine block as well (not sure if that is DC as well?)
When I first did testing (using a diode for rectification), I ran a jumper from the neg side of the battery to a bolt on the crankcase. So here I’m sure the engine block is being used as DC ground.
How does the stator being “grounded” to the engine block interact with the battery and DC circuitry also being ground to the engine block?
Trying to find a rectifier/regulator I was told that I couldn’t get it to work properly because I was using the engine block as ground/neutral for both AC and DC. I was told I needed a 2 wire stator so that I could isolate the AC from the rest of the DC system. But even without the Regulator (when just using a diode) wasn’t I already using the engine block for DC ground and AC neutral? Wouldn’t problems have shown themselves there?
I then came across the B&S 5/9 Amp regulated charging systems. These systems use a single wire stator that produces 28-40VAC RMS (28V for the 5A system and 40V for the 9A system) at 3600 RPM. This is very similar to the output of my stator/flywheel combo. This system uses a 2 wire rectifier/regulator. The two wire regulator is mounted to the engine via a bolt through its center. I assume since there is only 1 input lead and only 1 output lead, the R/R is “case grounded” through this mounting bolt. I assume this is using the same point on the block as ground/neutral for AC and DC.
Can anybody explain to me how this Briggs 5/9A regulated system works? Is a common ground for AC and DC even an issue? Is there a concept I am missing? Is there a hidden isolated ground being used somewhere somehow?