US 2019/0264950 A1Published application

Power supply system for an electrically powered resistive element

AssigneeSolarhotty Limited

InventorNeill HUMAN

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Abstract

A power supply system for an a.c. resistive element (10) comprises a first input point for an a.c. mains power source (14) and a second input point for d.c. power derived from photovoltaic panels and/or wind generators (24). Switches (18, 36) are provided between the power input points and the element (10). Timers (60, 62) are provided for delaying closing of that one of the switches (18, 36) that is open on change over from one power source to the other whereby the closed switch opens before the open switch closes. The voltage at the d.c. power input point is detected by a voltage sensor (42). The output from the sensor (42) powers an optical switch (46) which operates a relay (58) which in turn supplies power to one or other of the timers (60, 62) and one or other of the switches (18, 36).

Claims10

Dependent claims

A power supply system for powering a resistive element, the system comprising:

a first power input point for connection to an a.c mains supply;
first terminals for connection to said element;
a first switch having a closed position in which said input point is connected to said terminals and an open position in which said input point is disconnected from said terminals;
a first timer for delaying closure of said first switch;
a second power input point for connection to a d.c source of electrical energy;
second terminals for connection to said element;
means for converting the d.c input at said second power input point to a.c power at said second terminals;
a second switch having a closed position in which said converting means is connected to said second terminals and an open position in which said converting means is disconnected from the second terminals;
a second timer for delaying closure of said second switch;
and
a control circuit for detecting the presence of voltage at said second power input point and, upon the d.c voltage being detected being above a predetermined threshold level, in sequence opening said first switch and closing said second switch.

8 more elements

Dependencies are inferred from the claim text.