charging system conversion

[peanut budda]

Took on a project today involving swapping a Kawasaki engine over to a B&S engine. Only because of costs as this Snapper 48" wide area walk behind is a tired beast. This information provided is going to be dealing with an "unregulated" charging system for a non battery electric clutch only system.

I should mention electrical is something I am very good at. I have been formally trained in 12/24/36 volt dc electrical systems and have developed a taste for it throughout my mechanical career. I also like letting the "smoke" out and learning from these mistakes !!!

The Snapper mower had a 17 hp v-twin with a non-regulated charging system to power the electric clutch only. Briggs doesn't make such a beast and the customer wanted to keep it as cheap as possible and Briggs was having a sale. SO the mower was tossed my way with a 17.5 hp Briggs single cylinder and I was told to see if it's doable ?!?!?! Typical Briggs 12 volt system with a single wire stator, 9 amp regulated system and a fuel shut off in the float bowl.

Well as long as the rectifier is good from the old Kawasaki engine and you have a dual wire AC stator from another donor Briggs you can make this work.
Make sure you mark your ground and power wires on the rectifier as the two stator wires can be interchanged. Didn't research here so this may or may not matter so for safety's sake, let's go with it DOES matter. Clutch system fires right up and works as designed. I did not do an amp draw test to see what kind of amps this system could put out but I did some math in my head ( not always reliable LOL ) and figured with the magnets in the flywheel this system should have no problem loading up to 13 amps. Just hoping it doesn't load more keeping the customer from adjusting the clutch which could lead to a catastrophic melt down.

I suggest you DO NOT use this setup for anything other than a NON BATTERY installation...

I can supply part numbers or engine numbers if needed I just didn't bring any home with me today. If you need answers for this or anything else, I am always willing to help

[madmantrapper]

Amperage depends on the supply voltage and resistance of the coil. You could have a 12 volt system capable of 100 amp but if the coil resistance is 12 ohms, you are only going to have 1 amp flowing.

Paul

[RoyM]

I would like to know which alternator you used. This question comes up periodically and as you say Briggs does not make a suitable engine for this application.

[KE4AVB]

He didn't mention the wire colors coming the alternator in his post. I suspect he used the 10/16 version as the electric clutches that I have worked with requires around 5/7 amps depending the coil resistance. They will pull more in an unregulated circuit as voltage is not stable; otherwords, 6 amps @12VDC and around 8 amps @ 16 VDC on the average. BTW you don't need a battery in the circuit to use a regulated system just need the regulator/rectifier setup if you want a stable output. I would be very cautious using the system without the regulator as the PTO is going to overheat from the excess voltage and current draw causing early failure.

Briggs has two versions that are dual wire output. One is the dual circuit version which produces an 12v 3 amp DC current and an 14 VAC circuit for lighting. And then there is the 10/16 amp version. Identification as follows:

Dual Circuit wires > Black = AC Red = DC @3 amps
Has diode encased in wiring harness for conversion to DC in the Red lead which is a half wave rectifier setup.

10/16 amp version > Both wires are black. The output is AC before the regulator/rectifier unit. This voltage can be anywhere form 20vac to 30vac at 3600 rpm depending on the magnet size. Here the maximum amperage available is controlled by the flywheel magnets size.

V-twin Magnets
Small 7/8” x 21/32” (22 mm x 17 mm) 10 amp
Large 7/8” x 29/32” (22 mm x 23 mm) 16 amp

Others Briggs Magnets
Small Magnet 7/8” x 11/16” (22mm x 18mm) 10 amp
Large Magnet 1-1/16” x 15/16” (27mm x 24mm) 16 amp

The tri-circuit alternator which is a one wire version can also be use if you install a rectifier in the circuit. Again it produces around 28+ vac before the rectifier but it only to produces around 5 amps DC max when rectified.

I do have a copy of the Briggs Re-power alternator guide if anyone is needing it that explains most of the conversions that are needed.

[Deere2me]

I would like to know which alternator you used. This question comes up periodically and as you say Briggs does not make a suitable engine for this application.

An alt. ID can be had here :http://www.perr.com/tip17.html and/or here: [url]
http://www.tulsaenginewarehouse.com/dra ... wiring.pdf[/url]