Missouri Wind and Solar Freedom II PMG 24/48 Volt Permanent Magnet Wind Turbine Generator from NO COGGING, easy to turn - Cut in speed of 6 MPH Skewed stator core with high grade electrical steel and heavy duty copper windings 17 mm stainless steel shaft compatible with all Missouri Wind and Solar hubs 2x thick polished aluminum case Fits delco bolt patterns and mounts up to our standard mounting bracket Produces battery voltage at approximately 266 RPM in parallel; 133 RPM in series Produces twice (2x) the battery voltage at approximately 506 RPM in parallel; 253 RPM in series Produces four times (4x) the battery voltage at approximately 960 RPM in parallel; 480 RPM in series Wiring the output in series is only recommended for extreme high wind conditions. Some modified alternators use power to make power. Freedom PMGs use no input power. PMAs use a thin aluminum housing and the stator is not pressed in. The Freedom PMG features a very thick aluminum housing and a pressed in stator that helps with proper alignment and durability. PMAs have only two mounting holes. The Freedom PMG has four of them bolted tightly against the mounting bracket for secure mounting. Alternators and some PMAs have a weak rear bearing. The Freedom PMG utilizes two heavy duty bearings. Most car alternators and PMAs that are repurposed use low grade/high iron electrical steel which can create a lot of heat. The Freedom PMG uses high grade electrical steel and is optimized for efficient cooling Includes two heavy-duty rectifiers, one hub spacer stabilizer &amp; two bridge rectifiers Skewed stator core with high-grade electrical steel and heavy-duty copper windings 17mm stainless steel shaft compatible with all Missouri Wind and Solar hubs 2x thick polished aluminum case Zinc-plated 28 rare earth neodymium magnet rotor Specifically designed for wind turbines Fits delco bolt patterns &amp; mounts to our standard mounting bracket 3/8&#034; diameter bolt holes 1 15/16&#034; on center between mounting holes 5 7/8&#034; OD width 6 5/16&#034; tall 9 1/2&#034; overall length Shaft thread &amp; size: M16 - 1.5 (M=metric, 1.5 = metric thread pitch)