X16300B

SOLID STATE REGULATOR -12V NEG. GROUND- USED vintage 12-volt, negative ground solid-state voltage regulator primarily utilized in general aviation aircraft, specifically featured in the electrical charging systems of several Piper Cherokee models (such as the PA-28-140, PA-28R-201 Arrow, and PA-32 Cherokee Six).Technical Overview & DesignInternal Components: The legacy Prestolite maintenance documentation details that this solid-state system operates using three NPN silicon transistors.Built-in Filtering: It features an integrated internal capacitor (C1) designed to filter alternating current (AC) ripple and alternator diode switching spikes, allowing the system to handle "batteryless" emergency operation moments without blowing electronics.Transient Protection: It utilizes a specialized neon lamp (L-1) that serves as a robust surge suppressor against voltage spikes.Adjustability: Includes a built-in control potentiometer (P1) allowing a limited range to manually adjust and fine-tune system bus voltage, which is typically configured to maintain a continuous stable 14-volt bus charge.Critical Installation & Maintenance RulesThe Companion Overvoltage Relay: In standard Piper aircraft configurations, the X16300B regulator works in immediate tandem with a Wico X16799B Overvoltage Relay. If the regulator suffers an internal malfunction and commands full-field alternator output, this separate relay trips to isolate the field circuit and protect sensitive avionics from burning out.Thermal Management: The regulator must always be mounted directly to a bare metal plate or structural member away from high engine compartment heat zones to serve as a thermal heat sink.Grounding Requirements: For a secure negative ground loop, technical manuals demand a permanent, separate ground lead wire explicitly connected between the regulator’s mounting bolt and the physical frame of the alternator. Bad grounds are noted as the primary cause of charging fluctuation faults.