Remote dummy load
View Patent ↗The inventive dummy load is mounted on the input power cables of a traffic signal while managing the heat load generated by either a resistive and/or capacitive load. Using the inventive dummy load, there is no thermal path back to the light emitting diode (LED) board. The inventive dummy load may be easly installed, removed, or replaced. The dummy load can be retrofit to adapt to a new controller, either by adding to or replacing the dummy load after initial installation or by removing part or all of the dummy load. There is no need to breach the sealed lamp to adjust the dummy load. Thus, field-adjustments can be made. Further, the number of parts required to manufacture lamps for a variety of retrofit applications are reduced, which in turn reduces the cost and complexity of the lamp.
1. A traffic signal comprising:
a traffic signal housing,
electronics and an LED array inside the housing,
a power cable to power the LED array, wherein at least a portion of the power cable is outside the housing, and
a dummy load integrally connected to and supported by the power cable remote from the housing.
2. The traffic signal of claim 1 wherein the dummy load is removeably connected to the power cable.
3. The traffic signal of claim 1 further comprising a heat sink, wherein the dummy load is connected to the heat sink.
4. The traffic signal of claim 2 further comprising a heat sink, wherein the dummy load is connected to the heat sink and the heat sink and dummy load are removeably connected to the power cable.
5. The traffic signals of claim 1 wherein the dummy load is connected to the power cable using quick connect/disconnect connectors.
6. The traffic signal of claim 1 wherein the dummy load is connected to the power cable using a clamshell type connector or an insulation displacement connector.
7. The traffic signal of claim 3 wherein the heat sink is in direct thermal contact with the dummy load.
8. The traffic signal of claim 3 wherein there is a thermal interface between the dummy load and the heat sink.
9. The traffic signal of claim 1 wherein the power cable is a two-conductor cable.
10. The traffic signal of claim 1 wherein the power cable is a multi-wire input wire pair.
11. The traffic signal of claim 1 wherein the dummy load comprises a capacitive load.
12. The traffic signal of claim 1 wherein the dummy load comprises a resistive load.
13. The traffic signal of claim 1 wherein the dummy load comprises active and passive loads.
14. The traffic signal of claim 3 wherein the heat sink comprises a plurality of radial fins.
15. A method of retrofitting a traffic signal, comprising the steps of:
determining a desired dummy load based on at least one of a controller, a light array and any existing loads,
adding, removing or replacing a dummy load integrally attached to and supported by a power cable of the traffic signal via an insulation displacement connector to achieve the desired dummy load.