Equipment load safety circuit
AssigneeEntrelec-SSAC, Inc.
InventorKenneth C. Volz
Life of this patent
Estimating the term…
Abstract
A safety circuit according to the invention controls operation of an equipment load. A manual control switch of the safety circuit is connected in series with the equipment load for controlling the flow of electrical current to the equipment load. The equipment load and control switch series combination are further in communication with a relay contact switch of the safety circuit, which, like the manual control switch controls the flow of electrical current to the equipment load. Arranged in this configuration the equipment load operates only if both the mechanical switch and relay contact are closed. If either the manual control switch or the relay contact are open, the equipment load does not operate.
Claims51
A safety circuit for controlling operating of an equipment load, said safety circuit comprising:
- a control switch connected in series with said equipment load controlling a flow of electrical current to said equipment load;
- a relay contact in communication with said series connected control switch. also controlling a flow of current to said load, said load being operational only if said switch and said contact are closed to allow current to flow to said equipment load;
- a capacitor;
- and
- a relay inductor coil controlling operation of said relay contact,
- wherein said capacitor and inductor are selected so that said capacitor and said inductor form a series connected circuit operating at about a resonant frequency when said switch and said relay contact are open.
A safety circuit for controlling operation of an electrical load subsequent to a loss of supply power, said safety circuit comprising:
- a capacitor connected in parallel with a relay contact;
- a control switch connected in series with said equipment load;
- and
- a relay inductor coil controlling the opening and closing of said relay contact, said relay inductor coil connected in parallel with said series-connected control switch and equipment load combination, wherein said parallel connected combination of said relay inductor coil and said series connected load and switch is connected in series with said parallel connected combination of said capacitor and said relay contact, wherein said supply power is applied across said circuit so that said equipment load is operational only if said relay contact and said switch contact are closed.
An equipment load safety circuit comprising:
- a relay having an inductor coil and a relay contact, said relay contact controlling flow of current to said load;
- a switch controlling flow of current to said load;
- and
- a capacitor,
- wherein safety circuit is configured so that said inductor coil and said capacitor, when said relay contact and said switch are open, form a series-connected LC circuit having a resonant frequency of about a supply voltage frequency.
An equipment load safety circuit comprising:
- (A) a first circuit combination comprising a relay contact connected in parallel across a series-connected resistor and capacitor combination;
- (B) a second circuit combination comprising an inductor coil associated with said relay contact connected in parallel across a series connected switch and equipment load combination;
- wherein said first circuit combination is connected in series with said second circuit combination, and wherein said safety circuit is adapted to receive a supply voltage across said series connected first and second circuit combinations.
An equipment load safety circuit comprising:
- a relay having an inductor coil and a relay contact, said relay contact controlling flow of current to said load;
- a switch controlling flow of current to said load;
- and
- a capacitor,
- wherein said safety circuit is configured so that:
- (A) when power is applied to said safety circuit while said relay contact is open and said switch is closed, current flows through said capacitor, said inductor coil and said equipment load;
- (B) when power is applied to said safety circuit while said relay contact is open and said switch is open, current flows through said capacitor and said inductor but not said equipment load.
An equipment load safety circuit comprising:
- a relay having an inductor coil and a relay contact, said relay contact controlling flow of current to said load;
- a switch controlling flow of current to said load;
- and
- a capacitor,
- wherein said safety circuit is configured so that said inductor coil and said capacitor, when said relay contact and said switch are open, share a common current.
Dependencies are inferred from the claim text.