Transformer and control units for ac control
First Claim
1. A transformer unit comprising:
- a first connector for connection to an ac outlet to provide an ac supply to the transformer unit;
a second connector constituting an ac outlet of the transformer unit;
a triac, the first connector being coupled to the second connector via the triac to provide a controlled ac supply to the second connector;
an electrically isolating coupler for coupling a control signal to the triac for controlling conduction of the triac;
a transformer having primary and secondary windings, the primary winding being coupled to the first connector for receiving the ac supply; and
a third connector comprising at least three wires for connection to a control unit separate from the transformer unit, said at least three wires providing said control signal from the control unit, a low voltage supply for the control unit derived from the secondary winding of the transformer, and an indication of the timing of a waveform of the ac supply.
0 Assignments
0 Petitions
Accused Products
Abstract
A transformer unit connects to an ac outlet and provides ac controlled by an opto-coupled triac to another ac outlet. The transformer unit includes a transformer and a third connector for connection to a control unit separate from the transformer unit. The third connector provides the control signal from the control unit, a low voltage supply for the control unit derived from the transformer, and the timing of the ac waveform, provided by a zero crossing signal or an ac or rectified ac signal which can constitute the low voltage supply. The control unit, electrically isolated from the ac supply, can produce the control signal under manual control or automatically to gradually change the conduction phase angle of the triac. The brightness of a lamp connected to the ac outlet is thereby controlled manually or automatically to provide a simulated dawn or dusk.
33 Citations
20 Claims
-
1. A transformer unit comprising:
-
a first connector for connection to an ac outlet to provide an ac supply to the transformer unit;
a second connector constituting an ac outlet of the transformer unit;
a triac, the first connector being coupled to the second connector via the triac to provide a controlled ac supply to the second connector;
an electrically isolating coupler for coupling a control signal to the triac for controlling conduction of the triac;
a transformer having primary and secondary windings, the primary winding being coupled to the first connector for receiving the ac supply; and
a third connector comprising at least three wires for connection to a control unit separate from the transformer unit, said at least three wires providing said control signal from the control unit, a low voltage supply for the control unit derived from the secondary winding of the transformer, and an indication of the timing of a waveform of the ac supply. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14)
-
-
13. The control unit as claimed in 12 wherein the control circuit is responsive to initial application of said low voltage supply to produce said control signal to determine a relatively large conduction phase angle of the triac for supplying relatively little power to a load connected to the second connector of the transformer unit, and subsequently to produce said control signal to gradually decrease said conduction phase angle of the triac thereby to gradually increase power supplied to said load.
-
15. Apparatus comprising:
-
a first connector for connection to an ac outlet to provide an ac supply;
a second connector constituting an ac outlet;
a triac, the first connector being coupled to the second connector via the triac to provide a controlled ac supply to the second connector;
an electrically isolating coupler for coupling a control signal to the triac for controlling conduction of the triac;
a transformer having primary and secondary windings, the primary winding being coupled to the first connector for receiving the ac supply;
a rectifier and smoothing circuit coupled to the secondary winding of the transformer for providing a dc voltage;
a zero crossing detector arranged to produce a zero crossing signal representing zero crossings of a waveform of the ac supply; and
a control circuit powered by the dc voltage and responsive to the zero crossing signal to produce said control signal to control a conduction phase angle of the triac in successive half cycles of the waveform of the ac supply;
wherein at least the first and second connectors, the triac, the electrically isolating coupler, and the transformer are provided in a transformer unit, and at least the control circuit is provided in a control unit separate from the transformer unit for electrical connection to the transformer unit via a third connector having at least three wires, the control unit and the third connector thereby being electrically isolated from the ac supply. - View Dependent Claims (16)
-
-
17. A transformer unit comprising:
-
a first connector for connection to an ac outlet to provide an ac supply to the transformer unit;
a second connector constituting an ac outlet of the transformer unit;
a transformer having primary and secondary windings, the primary winding being coupled to the first connector to receive the ac supply;
a third connector comprising at least three wires for connection to a control unit separate from the transformer unit, said at least three wires providing to the control unit a low voltage supply derived from the secondary winding of the transformer and an indication of the timing of a waveform of the ac supply, and providing a control signal from the control unit to the transformer unit; and
a controlled device coupled between the first connector and the second connector and responsive to the control signal to provide a controlled ac supply from the first connector to the second connector, the control signal being coupled from the third connector to the controlled device in an electrically isolated manner. - View Dependent Claims (18, 19, 20)
-
Specification