System for control of lights and motors

A method for communicating between a first control circuit portion having a first current responsive element and a remote second control circuit portion having a second current responsive element over electrical power wiring of a building to control the operation of an electrical load, the first control circuit portion having a user actuable control for remotely controlling the load controlled by the second control circuit portion, the method comprising the steps of:

• conducting a load current through the electrical load from an AC voltage source;
• coupling the first current responsive element to the electrical power wiring, such that the first current responsive element conducts the load current;
• coupling the second current responsive element to the electrical power wiring, such that the second current responsive element conducts the load current whereby the first and second current responsive elements are in series connection with each other and the AC voltage source;
• establishing a current signal loop in the electrical power wiring between the first and second current responsive elements;
• transmitting control information over the electrical power wiring from the first control circuit portion to the second control circuit portion;
• and
• receiving the control information at the second circuit portion for controlling the load, wherein said step of establishing a current signal loop in the electrical power wiring comprises the steps of:
• providing first and second current transformers as the first and second current responsive elements, respectively, each of the first and second current transformers having a winding;
• and
• coupling the windings of the first and second current transformers to the electrical power wiring.

A load control system for controlling the power delivered to an electrical load from an AC voltage source, the system comprising:

• a load control device coupled to the electrical load for control of the load, such that a load current is operable to flow from the AC voltage source to the electrical load through the load control device, the load control device comprising a first current responsive element operatively coupled in series electrical connection between the AC source and the electrical load and operable to conduct the load current, the load control device further comprising a first communication circuit coupled to the first current responsive element for receiving message signals;
• and
• a two-wire remote control device comprising a second current responsive element operatively coupled in series electrical connection between the AC source and the electrical load and operable to conduct the load current, the remote control device further comprising a second communication circuit coupled to the second current responsive element for transmitting the message signals, the second current responsive element in series electrical connection with the first current responsive element and the AC voltage source;
• and
• wherein the first current responsive element and the second current responsive element are operable to conduct a communication loop current, the first communication circuit operable to transmit and the second communication circuit operable to receive the message signals via the communication loop current,
• wherein the first current responsive element comprises a first current transformer having a primary winding coupled in series electrical connection between the AC source and the electrical load, and a second winding coupled to the first communication circuit, and
• the second current responsive element comprises a second current transformer having a primary winding coupled in series electrical connection between the AC source and the electrical load, and a second winding coupled to the second communication circuit;
• wherein the primary windings of the first and second current transformers conduct the load current.

A two-wire load control system for control of the power delivered to a plurality of electrical loads from an AC voltage source, the plurality of loads and the AC voltage source coupled together at a common neutral connection, the system comprising:

• a load control device coupled to the plurality of loads and operable to individually control each of the plurality of loads;
• the load control device comprising a first current responsive element coupled in series electrical connection between the AC source and the plurality of loads and a first communication circuit coupled to the first current responsive element for receipt of a message signal for controlling the plurality of loads;
• a two-wire remote control device comprising a second current responsive element coupled in series electrical connection between the AC source and the plurality of loads and a second communication circuit coupled to the second current responsive element for transmission of the message signal for controlling the plurality of loads, the second current responsive element being connected in series relationship with the first current responsive element and the AC voltage source and the first and second current responsive elements conducting load currents to the plurality of loads;
• and
• a capacitor coupled in shunt electrical connection with the plurality of loads;
• wherein the capacitor, the AC source, the first current responsive element, and the second current responsive element are operable to conduct a communication loop current, the second communication circuit operable to transmit communication signals to the first communication circuit via the communication loop current, further wherein said first and current responsive elements each comprise a current transformer having a winding coupled for establishing a current signal loop for the exchange of the message signal, the windings of the current transformers coupled in series electrical connection with the AC voltage source and with each other.

A method for communicating a digital message from a two-wire remote control device to a load control device for independently controlling the power delivered to a plurality of loads from an AC voltage source, the method comprising the steps of:

• coupling the two-wire remote control device in series electrical connection between the AC source and the load control device;
• the two-wire remote control device comprising a current transformer having a winding in series electrical connection between the AC voltage source and the load control device;
• coupling a capacitor in shunt electrical connection across the plurality of loads;
• conducting a communication loop current through the AC source, the two-wire remote control device, the load control device, and the capacitor;
• and transmitting the digital message from the two-wire remote control device to the load control device via the current loop.