Voltage Regulation

... or lack of voltage regulation as the case is.  The alternator actually works too well.  I bought this cheap regulator/rectifier intended for scooters.  Its voltage stability is horrendous.  Naturally the Permanent Magnet alternator increases in voltage and frequency as I rev the S7 Deluxe engine.  The regulator should compensate for this and keep the voltage around 6.x volts and not too high such as the 7.x volts that I saw this morning.  At highway revs the ammeter was reading nearly full scale of 8 amps!  "That's WAY TOO much current", I said to myself as I sat beside the road this morning.  The voltage kept going up with the revs... its supposed to be regulated to limit the voltage so that the battery won't get overcharged.  Well, the reason I was sitting beside the road this morning was that the battery WAS being overcharged and had blown the 7.5 Amp fuse that I had installed in series with it.  I was trundling along until I dropped the revs and the alternator wouldn't produce enough voltage to keep the ignition going... at which time the bike stopped running at the intersection.

A quick disconnection of the stator leads and a jumper across the fuse, limped KYL95 back home to the workshop.

So, now I need to replace that cheap scooter regulator.  I imagine its just a simple series pass transistor regulator in there, and its not yielding good results.  The correct solution is to use a switching regulator.  Like this one:

http://www.national.com/pf/LM/LM3150.html#Overview

Oh, and I've purchased a resettable circuit breaker too.  I HATE fuses.

Awesome day!

Alternator - First Test on bike Unregulated

I finished the construction of the frame that holds the dynamo case to the front of the engine. My buddy Mark was kind enough to do the welding. A few minor adjustments and some precision holes drilled and I was ready to fully assemble the alternator to the bike.

First the cage must be installed with one arm out.

Then the magnet cup can be installed and the center bolt attached to the crankshaft and torqued down.  The fourth arm is then installed.

The casing can be placed over the cage and the screws installed where the pole shoes used to be.  The critical alignment of the stator inside the magnet cup was done with extreme care and precise drilling.  The stator will have some larger screws holding it to the plate in the final assembly, and a spacer to make sure it stays parallel to the plate.

Everything gets tightened.  In the final assembly the wires would go to the stock terminal block, but for this test without the regulator, I'm just going to hook some jumper leads out through the front.

Old KYL95 started on the first kick and we had LIGHT!!!!!  The automobile headlamp provided some visual load.  The voltage was around 6 at tickover.  It increased to 12 if I revved it up a little.  The regulator/rectifier will be installed in the electrical box, after the cage is sandblasted and painted.