Electrical transmission or interconnection systems – Plural load circuit systems – Circuit arrangements or layouts
Reexamination Certificate
2000-03-22
2002-04-02
Nguyen, Matthew (Department: 2838)
Electrical transmission or interconnection systems
Plural load circuit systems
Circuit arrangements or layouts
Reexamination Certificate
active
06365989
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the field of electronic controlling devices and methods. More particularly, the present invention relates to a controlling system for use in a room or area of a building such as a house or office, to provide various control methods for devices such as light fixtures, receptacles and electrical devices attached thereto, and heating devices, all of which operate from AC mains electrical supply voltages, by means of conveniently grouped or individual controlling devices which operate from an extra low voltage supply.
BACKGROUND OF THE INVENTION
For several years there have been known methods of controlling the brightness of incandescent light bulbs to create an ambiance in rooms. More recently there have been methods to control the brightness of fluorescent lamps. Still more recently there has been a desire to control the power output from a wall receptacle in order to vary the brightness of a lamp which is electrically attached to the receptacle.
Early methods of light dimming used large variable resistors that carried the same current as the dimmed light bulb. This method produced a great deal of heat and wasted a great deal of power. More recent methods make use of semi-conductor devices known as triacs. Several variations are known and they are based on the fact that power output from a triac can be controlled by varying the point in the AC waveform at which the triac is turned on. In so doing the portion of the AC waveform reaching the load is controlled. In order to control the point at which the triac is turned on, a variable resistance is provided and this is usually connected to a rotating knob or a sliding lever. In either case, the variable resistor, which is adjusted by a human being moving the knob or sliding lever is part of the same electrical circuit as the triac and is housed in a container together with the triac.
The previously mentioned triac and variable resistor, together with other electronic components such as capacitors are assembled into a device which has become commonly known as a dimmer switch. A typical dimmer switch is designed for installation in an electrical outlet box. Traditionally, when separate dimming control has been required for more than one light or group of lights, additional dimmer switches and additional electrical outlet boxes to contain said additional dimmer switches are required. Each dimmer switch requires a separate electrical outlet box. A problem arises when these traditional dimmer switches are grouped or ganged. Because the components produce heat while controlling a load, the rated load carrying capability for each dimmer switch must be reduced. In large rooms such as banquet rooms in a hotel for example, where several lights are controlled by a single dimmer switch, and several groups of lights are controlled from a common location, it is often necessary to use large dimmer switches with metal heat sinks attached. Alternatively, several individual boxes must be spaced apart on the wall. Neither situation is aesthetically pleasing.
Recently there has been a desire to control all lights and receptacles in certain rooms of homes so that a great degree of flexibility is available to the occupant for creating lighting scenarios. The occupant may want a bright room for entertaining and a dim room for relaxation. The occupant may wish to have all lights on, only one light on or no lights on. There are numerous possibilities if the occupant has control over all lights and receptacles. Because the receptacles are normally rated for 15 Amps and there is the possibility that a device requiring 12 amps may be connected to the receptacle, a dimmer switch controlling an individual receptacle must be capable of handling such a load. The dimmer switches normally found in homes are usually approved for use with a permanently connected incandescent load of 600 Watts. This load must be reduced if the dimmer switches are grouped or ganged. For example the Leviton 6602 dimmer switch has CSA approval as a 600 Watt device. This is reduced to 500 Watts if two are ganged and reduced to 400 Watts if more than two are ganged. If the occupant of a home had a desire to control, for example, six receptacles and two lighting outlets in a room, this would require using eight boxes and eight large dimming devices. This would be very expensive and would not be very pleasing to the eye since there is not enough space between wall studs in standard construction to allow for a continuous row of boxes.
Very recently, a number of companies have tried to provide methods of controlling individual devices in a room by providing control modules that plug into existing electrical receptacles and receive a control signal from a remote source. One such system, known as X10 uses the power line carrier method to convey a signal for control purposes. Another system, provides control by sending radio frequency signals to the controlled device. Both of the methods mentioned are referred to as wireless control and these systems were used because of restrictions in the electrical code which require that:
a) Wiring of extra low voltage systems must be physically separated from the wiring of mains voltage systems and if present in the same box must be separated by a suitable barrier.
b) The connection terminals for both systems must be accessible for the purposes of maintenance and inspection after installation.
Since electronic components normally operate at extra low voltages, there was no way to satisfy the code requirements where a wired system was desired, other than to use a central controlling panel. When a central control panel is used there must be a separate mains voltage cable run from the panel to each controlled device or to each controlled group of devices. This is very expensive to do and very wasteful of material. In comparison to the central panel method, the wireless methods allow for wire to be looped from one receptacle to the next in the normal manner and these systems are less wasteful of material. However, both the power line carrier method and the radio frequency method of wireless control experience problems from interference and this affects their reliability.
The power line carrier technology is vulnerable to power spikes on the electrical power system, over which it has not control. Power line carrier devices are expensive and must use other expensive components to attempt to deal with interference problems. Even with surge protection devices present in a circuit the reliability is questionable.
The radio frequency technology experiences a number of problems. For example, if a control signal is strong enough to travel from one end of a home to the opposite end of the home, it is also likely to be strong enough to enter a neighboring home. For this reason the radio frequency wireless method is claimed to be best suited where ample space exists between neighboring homes. When a lower signal strength is used, it may not be strong enough to pass through the walls in a home and signal boosting devices may be needed.
Additional problems occur for both systems, which can switch on power devices when they should be off. For example a baby monitor or a garage door opener from a neighboring home can cause false switching in the radio frequency system. A power line carrier signal can travel back through the electrical panel and onto the utility company power lines into a neighboring home, possibly causing fals switching.
Disclosed in the prior technical literature are several inventions which make use of wireless methods of control. Other inventions disclose control systems and wiring systems using a central control panel, for example Spira and Zaharchuck, Canada Patent No. 1243728 discloses a lighting scene control panel and control circuit. This system uses a central dimming panel and does not distribute control to individual controlled devices. With this system, individual mains voltage wires would be required to be routed from the central dimming panel to each light or group of lights to be dimmed. This sys
Black Lowe & Graham PLLC
Nguyen Matthew
O'Donnell Patrick
LandOfFree
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