Aeroelectric.com has one
Buly
>
> From: "John Downing" <downing.j@sbcglobal.net>
> Date: 2005/09/07 Wed PM 09:27:16 EDT
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Overvoltage control
>
> Does any one know of a simple inline overvoltage control that can be installed in the alternator power lead.  I have an internal regulator, alternator and the overvoltage units at ACS are part of a voltage regulator and quite pricey too.  JohnD
>