Patent Application
20090167537
The present invention relates to circuitry for detecting degraded electrical outlet circuitry and for preventing potentially dangerous conditions resulting therefrom.
The coming advent of plug-in hybrid electric and pure electric vehicles will soon be an integral part of the transportation system. The use of such vehicles raises a challenge that actually extends beyond the use of such vehicles, to the use of electrical appliances generally. The refueling or charging of these vehicles is from the power distribution grid, from basic duplex outlets in homes and workplaces. The refueling or charging operation can severely strain the 120 volt duplex connections of many homes, especially if those duplex connections are very old as is the case in many homes and workplaces. While such outlets can appear to be perfectly fine and may function for many lower demand appliances, these outlets may have degraded over years of service, setting up dangerous situations without the knowledge of the user.
The present invention provides a power supply apparatus for monitoring the condition of a power outlet. The device can include a power outlet; a power supply line, connected with the power outlet; and a sensor connected with the power outlet, the sensor being operable to generate a signal in response to a degradation of the power outlet.
The invention can provide a device and system for monitoring the condition of an electrical outlet such as a 110 volt or 220 volt outlet to alert a user to a dangerous situation and to interrupt power to the circuit in the event of the dangerous condition. The device can monitor the circuit for degradation to the electrical outlet. The system can include a temperature sensor, voltage meter or particle detector (smoke detector) connected with a power outlet. When a parameter of a circuit exceed a predetermined level (indicating the outlet has degraded to an unsafe level) a warning can be reported and if necessary power to the device can be adjusted or interrupted.
These and other features and advantages of the invention will be apparent upon reading of the following detailed description of preferred embodiments taken in conjunction with the Figures in which like reference numerals indicate like elements throughout.
For a more complete understanding of the nature and advantages of this invention, as well as the preferred mode of use, reference should be made to the following detailed description read in conjunction with the accompanying drawings which are not to scale.
The following description is of the best embodiments presently contemplated for carrying out this invention. This description is made for the purpose of illustrating the general principles of this invention and is not meant to limit the inventive concepts claimed herein.
As discussed above, the current and future advent of appliances such as electric vehicles have the potential to strain circuits in ways not previously experienced. For Example, duplex circuits in households and workplaces can be very old and severely degraded. While this degradation may not be a problem when using appliances that draw relatively small loads or that draw loads only for a relatively short period of time, a device such as an electrical vehicle can draw very high loads over an extended period of time, such as overnight. In a degraded duplex outlet, this can cause sever Joule heating, which can ultimately result in failure of the circuit, or could even cause a fire or other catastrophic event.
The present invention provides a device or system that can warn a user of the possibility of such an event, and that can prevent such an event from occurring in the first place, by regulating current flow or by giving a user advanced warning so that repairs can be made before a degraded circuit causes a circuit failure, fire or other catastrophic event.
With reference to
The device includes circuitry or logic 100 for determining that a temperature has reached an excessive level. First in a step 102 a base temperature can be established. This can be set by an operator or could be preset, such as to manufacture's specifications or by some other method. Then, in a step 104 power is transferred to an appliance of choice such as an electric vehicle. In a step 106, a temperature of the circuitry is measured and then, in a step 108 the current temperature of the circuit is compared with the base temperature to determine a temperature change or delta temperature (difference between the base temperature and the current temperature). If there is no temperature change, or if the temperature decreases, then the system continues to step 110 to continue detecting the temperature of the circuit, for continued comparison with the base temperature (returning to step 108).
If however, it is determined that the temperature has increased, the system continues to a decision step 112 to determine whether the temperature increases is beyond a predetermined acceptable first range or threshold (level 1). If the temperature increase is within an acceptable first range or threshold, then the system continues to step 110 to continue monitoring the temperature. If, however, the temperature increase exceeds the acceptable first range or threshold, then the system continues to step 114 to report that level 1 has been exceeded and possibly to or interrupt or reduce the power delivered to the appliance. If the temperature increase exceeds a first threshold (level 1), then the system continue to a decision step 116 to determine if the temperature exceeds a second threshold (level 2). If the temperature does exceed the second threshold (level 2), then the system continued to step 118 to interrupt power (such as by tripping a circuit breaker) and also to report that the second threshold (level 2) has been exceeded. The system then continues to step 120 to wait for an intervention (e.g. resetting the circuit breaker) or waiting for a system level reset contention.
With reference now to
As mentioned above, the invention can be embodied in an outlet to monitor the condition (ie. deterioration) of a power outlet circuit. With reference, then, to
With reference now to
Reporting Circuit Condition:
The invention can be embodied in a device incorporated into an outlet circuit itself to either alert a user of circuit degradation or to interrupt the circuit to prevent circuit failure. With reference now to
One or more of the receptacles 504 (or some other relevant part of the outlet 502) is connected with a temperature sensor 510 such as a thermistor. It should be pointed out that the invention is being described as using a temperature sensor 510, however the temperature sensor could be replaced with another device that can monitor some other parameter of the circuit such as a voltage or particle sensor. Therefore, the sensor 502 could also be a voltmeter or particle sensor.
The temperature sensor monitors the temperature of the tine 504 and, if the temperature exceeds a certain predetermined threshold, the temperature sensor 510 sends a signal to a warning indicator 512, which is activated to alert a user of a dangerous condition. The warning indicator can be a visual display (such as a steady or flashing LED) display, or could be an audible warning such as an alarm buzzer. Furthermore, the warning indicator need not be located directly at the location of outlet, but could be a remote device that can warn a user such as a home owner at some remote location, or could alert a centralized agency such as a local fire department, alarm company, etc. that a potentially dangerous situation exists.
With reference now to
With reference now to
With reference now to
Circuits 800(a) and 800(b) show the circuit during normal operation when there is no short to ground and no excessive temperature increase. As can be seen, the hot line 802 and the neutral line 804 both pass through the transformer. Since the currents are flowing in opposite direction through the lines 802, 804 there is a zero net magnetic field generated by the two lines, and the transformer 806 does not generate a current. Also, since no high temperature condition exists, the temperature sensor also does not generate a signal in the form of a resistance change. In this case, no current is applied to the solenoid 810 and the associated switch 814 remains closed.
The example shown as 800(c) shows the circuit in a ground fault condition. This is the situation where the hot line 802 has been grounded. In that case, current flows to ground and does not return through the neutral line 804. The transformer detects this net difference in currents between lines 802, 804 (which no longer cancel one another out) and generates a current 816 which at level 1 signals a condition of concern and level 2 condition that trips the solenoid 810 opening the circuit switch 814 and reporting the condition on 809.
The example shown as 800(d) shows the circuit responding to a high temperature condition, such as from outlet degradation described above. The temperature sensor 812 detects this increase in temperature and by generating a signal in the form of a resistance change in the temperature sensor 812. The sensor electronics circuitry 808 detects this resistance change and generates a current 818 to report a level 1 signal a condition and level 2 condition that trip the solenoid 810, thereby opening the switch 814 and deactivating the circuit. As can be seen, then, the temperature sensor 812 and sensor circuitry 808 used to prevent damage due to a degraded circuit, can be integrated into a system that gives the benefits of existing GFI function to utilize the solenoid 810 and switch 814.
The sensor circuitry 808 can be programmed to account for ambient conditions in order to prevent false trips. For example, the sensor circuitry can be programmed to monitor ambient temperature and factor that temperature when determining the amount of resistance change needed to trigger a signal to trip the solenoid 810. The sensor can, therefore, on a very hot day, determine that a resistance change of the temperature sensor is due to this ambient temperature increase on not to overheating of the circuit. Similarly, the sensor circuitry can, on a very cold day, determine that a lower increase in resistance is necessary to determine that the circuit has degraded and can generate a signal current 818 in response to a smaller resistance change of the temperature sensor.
While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Other embodiments falling within the scope of the invention may also become apparent to those skilled in the art. Thus, the breadth and scope of the invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
