The circuitry of the R448 Automatic Voltage Regulator (AVR) provides closed loop control of the alternator output voltage by regulating the exciter field current. The primary winding has a voltage in ratio to that of the alternator (characteristic shunt), the next has a voltage in proportion to the stator current (compound characteristic: booster effect).Which is powered by two auxiliary windings which are independent of the voltage equal circuit. The power supply voltage is rectified and filtered before being used by the AVR monitoring transistor. With PMG excitatioin, a permanent magnet generator (PMG) added to the alternator supplies the AVR with voltage which is free of the main alternator winding. This is built-in at the rear of the machine and connected to the R448 AVR, and the ST9 jumper must be disconnected.Quadrature droop adjustmentAVR Voltage adjustmentStability adjustmentLAM Threshold (underspeed) adjustmentExcitation ceiling adjustmentSelection of single phase or three phaseVoltage sensingSelection of normal or rapid response time50 Hz or 60 Hz frequency optionRemote voltage adjustment optionLAM enable/disable optionAlternator frame selectionExcitation system selectionInput voltage: 70-140V AC, (PMG, or auxiliary winding, single, three phases)Reaction is measured : 90-480V ACMAX. output :DC 10A 125VFunction: Built-in low-speed , over excitationLAMREGULATION: +/-0.5%Colour: blackMaterial: plasticPackage Contents:1 * Voltage RegulatorOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.