Alternator modification by ungrounding the brush and using a solid state regulator/rectifier.

[BobXs1]

Hello can anyone help me to understand how the alternator modification I've mentioned in the thread title works. I have a basic understanding of how the brushes magnetize the rotor but I'm wondering how the regulator portion of the solid state unit works to control it's voltage output. My regulator/rectifier is putting out 15v at a very high idle and 13v at a normal idle, but I'm wanting to understand how.
1972 model motorcycle
Stock engine
Modified charging system by isolating the inner brush and using a type A R/R.
Wire harness was made personally

 

[Jim]

There's 2 types of regulators, type A and type B.

The "A" type operates by regulating the ground to the rotor (outer brush).
The inner brush is supplied 12v any time the key is on and the regulator controls the grounding of the outer brush (completes the circuit) to control (regulate) the charge current from the stator to the rectifier.... and ultimately the battery.
This type is used on '80 and up bikes.

The type "B" operates by regulating the power to the rotor (outer brush).
The inner brush is grounded.... both with a black wire and through the screws holding it to the stator. The regulator controls (regulates) the power going to the outer brush.
This type is used on '70 to '79 bikes.

To convert a type B to a type A involves removing the 3 screws attaching the inner brush and replacing them with nylon screws to unground it from the stator. You then need to run a (switched) power wire to the inner brush and the outer (green) brush wire is connected to the regulator at the correct place.

Oh... and welcome to the forum!

 

[BobXs1]

I'm concerned about the 15v output charge of the unit. So much that I've installed a toggle switch to allow me to activate/deactivate the charging system as a whole. It's a point and condenser ignition system with led lighting. Thanks

 

[Jim]

15V at a high idle is on the high side. Do the volts continue to climb as you rev the bike, or do they stay at 15v? That's the main concern.
Also, you don't have to change it to a combined R/R. An automotive type B regulator might be a better option.
Have a read here.

 

[BobXs1]

15V at a high idle is on the high side. Do the volts continue to climb as you rev the bike, or do they stay at 15v? That's the main concern.
Also, you don't have to change it to a combined R/R. An automotive type B regulator might be a better option.
Have a read here.

Jim my first R/R unit was off an old XJ650 (type A) I had. It apparently was bad because it's output voltage read 17v plus..
I had this R/R unit of a 1980 model XS650 also so I changed to it and it put out a better (lower) voltage. It seems to level out at around 15.5v max but at a normal idle it drops to a tolerable 13-13.5v.

 

[Jim]

I had this R/R unit of a 1980 model XS650 also so I changed to it....

So you've already done the nylon screw mod?

 

[BobXs1]

So you've already done the nylon screw mod?

Yes sir I have but I'm not dedicated to it particularly, I could swap it back to the original type. Jim I'll add I dont have a factory wiring harness. Its a one I've made myself

 

[BobXs1]

I'll also add...............From the Factory any points model XS650 came with seperate Regulators, (B type) and seperate rectifiers. Any SS reg/rect used on a points model XS650 is aftermarket.

For anyone to help you solve problems it is best to let us know the year and model of your bike. If your not sure thaen post up the Vin # and pics of the bike. So may parts can swap between models and so may years have passed there is no way of telling when a PO has modified or swapped parts around............Posting pics I, and others, will spot any changes made that may require a different answer to a specific part, when an answer to the Model may not be right

 

[BobXs1]

I understand what you are saying. I do not have any good pics currently but I will edit the post to show more details of the motorcycle.

 

[BobXs1]

Think of the SS Reg/Rect as 2 different types. An A type and B type charging system..................with a third option using the A type SS Reg/Rect on a B type charging system

The first type, (Yamaha supplied and Aftermarket) is for the 80-83/4 factory electronic ignition, (TCI), with both brushes energized and the unit is Earthed/grounded in its wiring to the loom wiring................This is also classed as an A type charging system

The second type is and aftermarket SS Reg/Rect for points models from 1970-1979 in the US and for all points models else-ware up to 82/3 with one brush energized and the other brush is earthed/grounded..................This is also classed as a B type charging system

Third option................Is to use a Factory or aftermarket SS reg/rect, for a TCI ignition model, (80-83/4 B type system), and use it in a points model, (1970-1979 in the US and for all points models else-ware up to 82/3, A type system), and this has to have modifications done to the wiring to power/enrgize the second brush and to also change the screws on the old Earth/ground brush to nylon, so as to isolate that brush and change it from an earth/ground to a powerd/energized brush

Wiring in an Aftermarket SS/Reg/Rect for a points model, B type charging system.
https://www.xs650.com/threads/wiring-in-a-70-79-combined-reg-rect-to-a-points-model-xs650.52339/

On your SS Reg/rect The charging output is in line with a normal operating SS Reg/Rect. As long as it is working, (not charging when the battery is fully charged). Reg part of the SS Reg/Rect cuts power to battery when the battery is fully charged. If your battery is failing and wont hold a charge the Reg part of your SS reg/rect will continuously charge the battery and this can cause the battery to overcharge, heat up and in an extreme case blow up.

The other componant in this chain is the rotor. If the reg is continuisly letting power from the rotor charge a faulty battery then the rotor doesn't get a rest and will burn out one or more of its phases. This in turn means the battery cannot get charged and ultimately you can get stranded

 

[BobXs1]

Ok I'll start by saying my battery is a known good one. I've installed a toggle switch to control the power to the inner brush just in case it does start to over charge.
In a charging system like mine where both brushes are capable of carrying current how does the regulator regulate the grounding and un-grounding of the outer brush (green wire)? Because the black wire (inner brush) is constantly hot as long as I have power switched on to it.

 

[Jim]

Ok I'll start by saying my battery is a known good one. I've installed a toggle switch to control the power to the inner brush just in case it does start to over charge.
In a charging system like mine where both brushes are capable of carrying current how does the regulator regulate the grounding and un-grounding of the outer brush (green wire)? Because the black wire (inner brush) is constantly hot as long as I have power switched on to it.

Not sure I understand your question?

 

[5twins]

But both brushes in your set-up don't carry current, only the inner one does. The outer one is fed a regulated ground (switched on and off) by the regulator. When the regulator senses the battery charge is too low, it sends a ground to the outer brush. This completes the circuit, energizes the rotor, and the alternator starts charging.

I think your 15+ volt max output is too much. Ideally you want to see low to mid 14's. A local guy had an output like that and I told him it was too much. But he said the mechanic where he worked told him it was fine. Well, OK then, lol. It took about a month but he ended up burning out his rotor. A problem we could have fixed with a $20 automotive regulator now needed a $100 rotor, lol.

 

[BobXs1]

[QUOTE="Jim, post: 744223, member: 27347
Not sure I understand your question?
[/QUOTE]
Lol that is an all familiar response that I hear quite often Jim.

 

[BobXs1]

But both brushes in your set-up don't carry current, only the inner one does. The outer one is fed a regulated ground (switched on and off) by the regulator. Wuhen the regulator senses the battery charge is too low, it sends a ground to the outer brush. This completes the circuit, energizes the rotor, and the alternator starts charging.T

I think your 15+ volt max output is too much. Ideally you want to see low to mid 14's. A local guy had an output like that and I told him it was too much. But he said the mechanic where he worked told him it was fine. Well, OK then, lol. It took about a month but he ended up burning out his rotor. A problem we could have fixed with a $20 automotive regulator now needed a $100 rotor, lol.

I agree with you about the excessive voltage output and the Type B separate regulator and rectifier you've suggested. I also understand more now how the regulator regulates the output voltage of the stator. Thanks for that. Just for the sake of curiosity I've ordered a new Type A S/S regulator/rectifier off Amazon. If it corrects my problem all the better, if I get the same results with it as I did the current one I can return it and I will start over and build the Type B regulator/rectifier like you suggest. Ive read the threads you've sent me and like the idea of it. I might need some guidance on wiring into my stator and brush wires. I have none of the factory loom or pin connectors. Thank you

 

[BobXs1]

But both brushes in your set-up don't carry current, only the inner one does. The outer one is fed a regulated ground (switched on and off) by the regulator. When the regulator senses the battery charge is too low, it sends a ground to the outer brush. This completes the circuit, energizes the rotor, and the alternator starts charging.

I think your 15+ volt max output is too much. Ideally you want to see low to mid 14's. A local guy had an output like that and I told him it was too much. But he said the mechanic where he worked told him it was fine. Well, OK then, lol. It took about a month but he ended up burning out his rotor. A problem we could have fixed with a $20 automotive regulator now needed a $100 rotor, lol.

5twins I'm sure you have better things to do today than try to help me understand solid state type A regulator/rectifiers but I'm having a hard time wrapping my head around the understanding of it. Most normal folks would accept the fact that A it works or B it doesn't but I have alot of spare time on my hands and don't like TV.
I understand that both brushes would carry voltage through them to magnetize the rotor and one grounds intermittently controlled by the s/s unit to control voltage output but when I check the voltage at the brushes with the engine not running and the power to the brushes switched on I only get voltage to one brush. That being the black wire or inner brush

 

[jetmechmarty]

This is not solid state, but it may be the explanation you're looking for.

 

[BobXs1]

This is not solid state, but it may be the explanation you're looking for.

Marty where have you been all my life?

 

[BobXs1]

But both brushes in your set-up don't carry current, only the inner one does. The outer one is fed a regulated ground (switched on and off) by the regulator. When the regulator senses the battery charge is too low, it sends a ground to the outer brush. This completes the circuit, energizes the rotor, and the alternator starts charging.

I think your 15+ volt max output is too much. Ideally you want to see low to mid 14's. A local guy had an output like that and I told him it was too much. But he said the mechanic where he worked told him it was fine. Well, OK then, lol. It took about a month but he ended up burning out his rotor. A problem we could have fixed with a $20 automotive regulator now needed a $100 rotor, lol.

Hey I appreciate your offering to help me. Im gonna try and do the separate regulator/rectifier mod like you have recommend using the automotive regulator. Can you help me with understanding how I would wire it all up to my engine? I've read the links you sent me and it's written in a format that the motorcycle the mod is being performed on has a factory wiring harness and connectors. I have a 71 model engine and no factory harness, connectors or switches ect. I understand the rectifier portion of connecting the wires but how do I incorporate the regulator with no prior factory wiring harness. I am using a battery and the points ignition just to let you know and I have the ignition already wired and working. Thanks for your help

 

[5twins]

If you have the early type alternator (with the full time grounded inner brush), I would leave it stock. Don't do the nylon screw mod and unground the inner brush. Since you have to buy a regulator anyway, just get the proper power regulating 'B' type that's needed for the early alternator. The VR115 is a common one we use but go to that link in Jim's post #4 above for a list of part numbers from other manufacturers.

The new regulator will have 4 wires. The green goes to the outer brush and is the regulated power signal (power turned on and off) that controls the charging output. The black wire is a ground. It can be run to the inner brush or just grounded to the frame or engine somewhere. The battery box is rubber mounted so it is not a suitable connection point for a ground wire. The last two wires, a red or orange and a yellow, will be combined and hooked to a switched power wire in the harness, one that only has power when the key is on.

On the original set-up, a black wire was run from the grounded inner brush to the regulator. This wasn't supplying a ground to the brush as it's mounting screws ground it. It was sending a ground to the regulator. I'm not sure why Yamaha chose to do it this way rather than just ground the regulator elsewhere. So, if you do ground the regulator elsewhere, you don't even need the black wire run to the inner brush.