Stabilized DC power supply device

Claim 1

A stabilized DC power supply device for providing a plurality of different DC powers with regulated voltage levels and with different rated currents, comprising: a DC power source, a main DC-AC inverter circuit coupled to said DC power source and providing high frequency AC outputs from said DC power source, said main inverter circuit comprising transistor circuit means and an inverter transformer coupled to said transistor circuit means, said transformer having first, second and third secondary windings, from each of which a high frequency AC output is taken out, a rectifier circuit coupled to said first secondary windings of said inverter transformer for rectifying the AC output presented on said first secondary windings of said inverter transformer to provide a DC output, a transistor switching regulator circuit coupled to the DC output from said rectifier circuit and providing a predetermined first DC power with a regulated voltage level at a DC output thereof, a DC-DC converter circuit coupled with said DC output of said transistor switching regulator circuit, a transistor series regulator circuit coupled to an output of said DC-DC converter and having an output providing a predetermined second DC power with a regulated voltage level and with a lower rated current than said first DC power, a magnetic amplifier regulator circuit coupled to said second and third secondary windings of said inverter in said main DC-AC inverter circuit, said magnetic amplifier regulator circuit having an output providing a predetermined third DC power with a regulated voltage level and with a higher rated current than said first DC power, means coupled to said magnetic amplifier regulator circuit for detecting overvoltage of the output from said magnetic amplifier regulator circuit and having an output indicating an overvoltage condition, said overvoltage detecting means including a zener diode coupled to said magnetic amplifier regulator circuit and which conducts when the output voltage of said magnetic amplifier regulator circuit exceeds a predetermined voltage level, a transistor coupled to said zener diode so as to conduct when said zener diode is conducting, and a relay coupled to said transistor and which is switched on when said transistor is conducting. means coupled to said magnetic amplifier regulator circuit for detecting overcurrent of the output from said magnetic amplifier regulator circuit and having an output indicating an overcurrent condition, said overcurrent detecting means including an overcurrent relay coupled to said magnetic amplifier regulator circuit and which is switched on when the output current of said magnetic amplifier regulator circuit exceeds a predetermined current level, and control means including a thyristor coupled to said main DC-AC inverter circuit and to said relays of both said overvoltage detecting means and said overcurrent detecting means, said thyristor being actuated responsive to at least one of said relays being switched on, and a further relay coupled to said thyristor and to said main DC-AC inverter circuit, said further relay being switched on when said thyristor is actuated to short-circuit a partial circuit path of said main DC-AC inverter circuit to stop the operation of said main DC-AC inverter circuit.