Folks Right now I'm on a huge learning curve with my permanent magnet alternator and regulator. It would appear there are two basic types of regulator.
The first is called a "shunt" and regulates by diverting excess power (voltage) to a heat sink or some other load besides the battery. The other is called a "series" and it operates by using thyristors to switch the output leads from the dynamo on and off thereby regulating voltage. The latter can cause reverse voltage spikes as it switches leading to noise and other damage. If you overspin the former it can overheat and fail unless it has another load (eg landing light) whilst in the latter the thyristor duty cycle can be exceeded (it can't switch on and off quick enough without overheating). The result in both can be run away overvoltage and cascading failure....multiple smoke columns. Further, if the signal wire (yellow one in Kubotas) is disconnected, eg., by turning off the master switch in flight, then the reference zener diode thinks the battery is at zero voltage and will force the regulator to again run away in both shunts (trys to charge an apparently flat battery but can't as it actually charged up and so diverts full power to the heat sink) and series (thyristors kept on). So...don't overspin and don't disconnect whilst running unless you can switch out the unregulated dynamo leads (blue ones) at the same time, eg., via a relay off the master. There is an interesting thread on this topic lead by Mike Sharkey on the KR net archives around the end of January in 1998 and a google search on shunts and series regulators will give thousands of sites. I'm leaning more and more towards a small field controlled alternator. Does anyone know of a unit no deeper than about 3" with similiar mountings. Hope this warning can save someone the expense of a new regulator. Regards John and Janet Martindale 29 Jane Circuit TOORMINA NSW 2452 AUSTRALIA ph: 61 2 6658 4767 email: johnj...@chc.net.au
