• Mulit-voltage inverter with center switch for uninterruptible power supply
• Low-cost standby power system
• Dynamic voltage regulation stabilization for AC power supply systems
• Software method for adaptive determination of battery run-time
• Advanced uninterruptible power system
• Software method for line power monitoring
• Automatic inverter and battery testing
• Low-cost front panel display for electronic equipment
• Brushless exciter for controlling excitation of a synchronous machine
• Simplified gating arrangement for thyristors in a tap-changing regulator
• Microprocessor controlled overload relay
• Time-ratio-control for large contactor coils
• Electronic control system for overload relay
• Solid state protection system and method
• Low-cost signal processing system for overload relay
• Circuit interrupter having unique flash plates
• Arcless tap changer for voltage regulator
• Electronic means to provide assisted mechanical switching
• Power circuit for variable frequency, variable magnitude power conditioning system
• Adjustible speed electric motor drive having constant harmonic content
• Inverter having constant frequency chopper synchronized to modulation frequency
• Transistor inverter motor drive having voltage boost at low speeds
• Transistor bridge inverter motor drive having reduced harmonics
• Electronic commutation system having motor stator windings in push-pull
• Control having conduction limit means to protect power switches
• Electronically commutated motor
• Variable duty cycle traction motor control providing controlled plugging
• Variable time-ratio control having speed potentiometer failure protection
• Control for commutatorless motor
• Capacitive position sensor
• Electronic scanpoint matrix with switch monitoring
• Phase shift detector for reverse power flow control
• Sink-source voltage regulator