OVERLOAD PROTECTING SYSTEM FOR STABILIZED POWER SOURCE

PURPOSE: To rationally perform protection countermeasure suitable for overload state when the light overload caused by load fluctuation or the like or the heavy overload caused by load short-circuiting, etc., is applied to a stabilized power source. CONSTITUTION: An auxiliary output voltage Vc of a stabilized power source 60 is always monitored by a voltage monitoring means 30 and when that voltage rises to a prescribed threshold value after start, an operation of a control system 10 of the stabilized power source 60 is started. In the first overload state in which that voltage Vc is lowered under a first critical value by load short- circuiting, etc., the operation of the control system 10 is stopped until the stabilized power source 60 is started again by the manual operation of an input switch 1 or the like and a normal output voltage Vo of the stabilized power source 60 is monitored by an overload detecting means 40 built in the control system 10. In the second overload state in which that voltage Vo is lowered to a second critical value by load fluctuation, etc., the operation of the control system 10 is temporarily stopped by operating a voltage control means 50 by an overload signal So and then automatically started again later after the lapse of a prescribed time.