Electrical power supply for short term power interruptions

A direct current power supply for instantaneously providing tens of kilowatts of electrical energy for brief periods, such as 100 ms, during momentary power interruptions between a load and an electrical power source having a supply voltage includes a capacitor having an initial voltage charge preferably greater than the supply voltage. The cathode of a zener diode is operably coupled to the capacitor. The anode of a second diode is operably coupled to the anode of the zener diode. A solid state switch has a power input operably coupled between the capacitor and the cathode of the zener diode, a power output operably coupled between the anodes of the zener diode and second diode, and an enabling input, so that the switch may be triggered to conduct electrical power whereby voltage from the capacitor is conducted through the switch to the anode of the second diode when an enabling signal is provided to the enabling input. The anode of a third diode is operably coupled to the voltage supply, and the cathode of the third diode is connnected to the load. The cathode of the second diode is connected between the cathode of the third diode and the load. A low supply voltage detecting circuit operably coupled between the enabling input of the solid-switch and the supply voltage provides the enabling signal to trigger the switch into a conduction mode when the supply voltage is below a predetermined voltage level.