Regulator/Rectifier

[frankfast]

s-l640.jpg

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Anybody familiar with this regulator/rectifier and it's connections?

[ducwiz]

As far as I know this a SAPRISA (E) 12 Volt R_R used in the spanish made DUCATI parallel twins. It cannot be used on the w/c singles for a 12 Volt conversion, because it is designed for a 2-phase circuit with center-tap, right as the 6 Volt version in the singles. Both alternators have 2 yellow and a single red wire.
It might work in the 750/860 L-twins.

Hans

[frankfast]

Are you saying that it CAN be used on 6-volt W/C singles?

[ducwiz]

No, you can't use it ! For a conversion, you need an R-R with an internal rectifier bridge, not only two SCRs.

Hans

[frankfast]

I'm not interested in converting to 12 volts and purchased this because it was advertised for singles. If it can't be used I'll keep it in my unused parts museum. I'm trying to find an inexpensive R/R for a three wire alternator for my W/C Scrambler with a schematic.

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Is this the proper schematic for a W/C Scrambler

[ducwiz]

OK, I have to be a bit more precise: It can be used for some newer spanish singles, which were originally produced with 12V systems. Italian w/c singles always had 6V systems with different alternator windings. If you connect it to an italian 6V alternator it will not give the maximum electric power (90/75 W), and charging at low revs is bad, especially with headlights switched on.
A 6V R-R with a moderate price seems to be still in production, or at least available:
https://www.ebay.com/itm/1967-72-Ducati-160-250-350-450-Morini-125-250-6V-14A-voltage-regulator-179006/173881283954?hash=item287c21d572:g:tbsAAOSwBKBcvmS~
https://www.ebay.com/itm/REGOLATORE-DI-TENSIONE-6V-14A-MOTO-DEPOCA-DUCATI-SCRAMBLER-250-350-450/362771737691?hash=item5476e16c5b:g:n9EAAOSwTrldlNAF#shpCntId
As a 12V R-R from a chinese scooter is available for less then 10$, so you might reconsider your decision against a conversion to 12V.

Hans

[frankfast]

I thank you for your time and response. I don't mean to persist but since I've already purchased this unit I would like to run the bike with it connected and then check the charge. I have connected the terminals according to the schematic above without success in getting a spark and I'm suspicious that the terminal marked 'brown' is not meant for the coil. I do get spark when I abandon that terminal and connect the coil to a hot lead directly from the battery and am certain that the bike will run but not sure it will charge in that configuration. Not having a schematic including this particular R/R, would you expect that the terminal marked 'brown' is meant to be connected to the coil? If so, the R/R is probably not working as it should. The unit may still charge without a connection to that terminal.

[ducwiz]

The SAPRISA R-R works the same way as the original DUCATI R-R, and features the same terminals, clearly visible in the picture; 2x yellow/1x red from the alternator stator, 1x brown from the ignition switch, 1x red from/to battery +.
Very important: The R-R's case has to be properly gronded. Best method: make a short piece of cable with eyelet terminals on both ends, and connect the R-R's case via one of it's mounting screws directly to battery- ! If it has a weak ground connection or none at all, it will not work !

Your "test" will not damage anything as long as the R-R is properly connected, and the battery and all loads in the electric circuit of your bike are made for 12V. If you use it with a 6V battery, it cannot do anything at all, because 6V is to low to start the electronic circuit inside!
You wrote

I'm not interested in converting to 12 volts

. So why you want to use this R-R anyway and make a conversion against your intention? It will definitely source 12 Volts into your wire loom, but only in combination with a 12Volt battery ! Hence, you have to change the battery, all incandescent bulbs, the ignition coil, the horn, otherwise all these parts will be supposedly damaged/burned.
If the "brown" terminal is left open, the R-R cannot pass any power to the battery and loads, as this terminal is it's control input - here it "sees" or "measures" the system voltage. So, the brown wire in the bike's loom has to be connected to the "brown" terminal. Voltage appears on this wire, when you switch on ignition. But - if this brown wire's opposite end was connected to the wrong coil terminal (the points side!), sparking may be inhibited, and the R-R even might be damaged. So, check carefully if the connection is in the right manner, at the primary input terminal of the coil.
Generally, use a fully charged battery (12 Volt) while checking/measuring.

good luck! Hans

p.s. Please, quote in your profile where in this crazy world you are located

[frankfast]

Took the Saprisa R/R off the bike and replaced it with a bridge rectifier. As per a discussion with Dew-Ca-Ti Bob a long time ago, connected one yellow lead from the alternator to an AC terminal on the rectifier. Connected the red lead to the + terminal and ran a ground to the - terminal. I left one of the yellow leads disconnected and one of the AC terminals abandoned. Except for the brake light I don't usually have the lights on and I don't ride at night. Other than concern of the bike overcharging or undercharging the bike will run since I now have a healthy spark. If I find that I'm overcharging I could incorporate a zener diode to soak up any excessive charge. Since the alternator is operating at half capacity I doubt that will be a problem. If I'm undercharging I could connect the other yellow lead from the alternator. I could then use a zener diode to absorb the excessive charge. It's definitely a balancing act. According to Dew-Ca-Ti Bob this system will work with the addition of a switch or two but I don't know if he ever expanded on it with a schematic.

[tobydmv]

Took the Saprisa R/R off the bike and replaced it with a bridge rectifier. As per a discussion with Dew-Ca-Ti Bob a long time ago, connected one yellow lead from the alternator to an AC terminal on the rectifier. Connected the red lead to the + terminal and ran a ground to the - terminal. I left one of the yellow leads disconnected and one of the AC terminals abandoned. Except for the brake light I don't usually have the lights on and I don't ride at night. Other than concern of the bike overcharging or undercharging the bike will run since I now have a healthy spark. If I find that I'm overcharging I could incorporate a zener diode to soak up any excessive charge. Since the alternator is operating at half capacity I doubt that will be a problem. If I'm undercharging I could connect the other yellow lead from the alternator. I could then use a zener diode to absorb the excessive charge. It's definitely a balancing act. According to Dew-Ca-Ti Bob this system will work with the addition of a switch or two but I don't know if he ever expanded on it with a schematic.

If you dont need lights and just want to ride the bike and maybe charge the battery your pretty much there already. My scrambler only uses a bridge rectifier and I run the bike off the battery. If thats what you are after I could share a wiring diagram but its pretty straight forward. Just run a hot wire from the battery to a toggle or push button switch and then to the coil. The coil should ground to the points and cap/condenser. Run the stator leads into the rectifier and then directly back to the battery.

I used to run something similar on my old Motobi street bikes and mounted the rectifier in the headlight shell. I had a LED tail light at the time which may have prevented the headlight from burning out,not sure the output was enough to pop the bulbs. You could also just change your bulb to 12v and not worry about it...