Circuit breaker remote activation and anti counterfeit function

Background Art

A large number of circuit protection devices are copied mainly because of their relative mechanical and electronic simplicity. In the vast majority of cases the external appearance of most copies compares with a genuine product whilst their interior construction is somewhat different from the genuine design resulting usually in a much reduced performance and in some cases dangerous behaviour.

A number of solutions exist to identify counterfeit products, for example serial numbers, holograms etc, and while these do allow manufacturers to trace product and identify how counterfeit products are entering the distribution channels there is no real method to distinguish between a genuine product and a copy no mater how sophisticated it is at the point of sale.

The purpose of this invention is to disclose a method of product activation at the point of purchase thereby allowing end users and installers to clearly identify genuine parts from counterfeit ones. Additionally this method allows manufacturers to offer greater support to end users and installers.

Summary of invention

All electro-mechanical circuit protection devices have an active protection component this can be a bi-metallic or eutectic element which is connected to the main switch located in the main current path, in the former case this has a resistance which changes with the amount of current flowing through the component, this change in resistance can be measured. In the case of the bi mental this resistance value significantly changes with increased current flow thus inducing a large deflection of the bimetal due to differential thermal expansion of the differing bimetal materials.

As an example, a typical circuit breaker will incorporate a short circuit solenoid and a bi metal element. During manufacture the bimetal is calibrated using a known current and published time current characteristics to set the required performance for the circuit breaker rating. The adjustment changes the position of the bi metal strip in relation to the circuit breaker main switch contacts & mechanism and hence the amount of deflection caused by the heating of the bi metal by the overcurrent required to cause the contacts to separate under over current conditions.

The proposed invention uses a fixture at the point of sale to measure the time current characteristic of a circuit protection device or a plurality of circuit protection devices, and verify this characteristic against known data for each individual circuit protection device. Once validated the overcurrent characteristic is re-calibrated in a pre determined manner to enable each circuit protection device to function at its rated current.

During the manufacturing process each completed circuit protection device is tested and calibrated. The calibration process uses a fixed current applied to the circuit protection device to measure the time taken for the circuit protection device main contacts to open. The calibration screw that acts on the bi metal is adjusted to either increase or decrease the trip time in order to calibrate the device. The amount of adjustment is calculated with reference to the time current characteristic of the bi-metal being used.

The proposed invention requires each circuit protection device after testing and calibration to be deliberately taken out of calibration in a pre determined manner by the manufacturer by adjustment of the calibration screw therefore ensuring the circuit protection device main contacts will always be open due to the effect of the position of the bimetal on the contact mechanism thus rendering the device un-usable. The amount of adjustment is recorded and stored within a database located and secured under the manufacturers control along with the device serial number and the measured resistance of the main current path and the external marking data that is a requirement of the relevant device standard. The device is then distributed to the point of sale in a safe and in-operable condition. The amount of adjustment to the calibration screw prior to distribution can be either random or from a set of predetermined values i.e. part or full rotations of the calibration screw

Brief description of drawings

Figure 1 is a block level diagram of the fixture and the components within it.

The invention is a device 100 incorporating a resistance measurement means 106, current generation means 105, timing means 107, calibration screw adjustment means103 & 104 and calibration screw security device 112 which when coupled to a circuit breaker101 can measure the main circuit resistance path, time taken for the breaker to respond to a fixed current generated by the fixture, validate the measured parameters with a secure remote server111, apply an adjustment to the calibration means of the circuit breaker and secure the final position of the circuit breakers calibration screw 102.

The calibration adjustment is done by using a motor unit 104 coupled through a shaft to a blade 103 which interfaces to the calibration screw 102 of the circuit breaker 101. The angular rotation of the shaft is measured by either a linear or rotary encoder. The amount of rotation is controlled by an electronic controller 108 which receives adjustment parameters and turns the calibration screw 102 the required number of full or part turns as required. The electronic controller 108 can be embedded within the device or be a control programme running on an external personal computer.

There are a number of options to secure the circuit breakers 101 calibration screw 102 once adjustment has completed. The fixture may incorporate a glue dispense system place a small amount of glue onto the calibration screw 102, an alternative solution could be a heating element which heats the circuit breaker 101 casing around the calibration screw 102 deforming it in a manner to prevent further adjustment or a means of inserting a small plug into the aperture in which a calibration screw 102 is accessed.

Circuit breaker identification is by a serial number printed on the exterior surface of the breaker. This is sent along with measured parameters of the circuit breakers performance, namely the primary current path resistance, and the time to trip when a fixed current is applied by the current generation means 105 to a validation server 111. Measurement of the primary current path is achieved by connecting resistance measurement means106 between the line in and line out phase or phases of the circuit breaker 101. Time to trip the breaker is measured by monitoring the line in and line out phases of the circuit breaker 101 when a fixed current is applied to the line in phase or phases of the circuit breaker 101. The timing means 107 measures the time to interruption of the test current at the circuit breaker 101 output.

To start the validation process the user inputs the device serial number and other relevant information (end customer, application type, purchase date etc) using either a manual or automated procedure. The fixture 100 measures the parameters of the circuit breaker 100. This measurement data is sent electronically to the manufacturer's validation service or server 111. The stored data for the device is looked up in the manufacturing database and then compared with the measured data obtained by the fixture 100. If there is a correct comparison and the device is judged to be valid the required adjustment parameters for the calibration screw 102 are transmitted to the fixture100.

The device is then activated by starting the fixture adjustment method which applies the required adjustment to the calibration screw102, the calibration screw security 112 is then applied to prevent the calibration screw 102 from being tampered with or its position changed. When completed the fixture 102 applies the fixed current to verify the device performance in an over current condition and in relation to the exterior markings required by the relevant device standard and these values are sent to the validation service 111 for updating in the manufacturers database.

A further aspect of this invention is a method of device activation incorporating a circuit protection device 101 having a calibration means 102 a fixture 100 measuring parameters of said circuit protection device to enable device identification said measurement data to be transacted between the said fixture 100 and a remote authentication server 101 which validates the identity of the said device and transmits adjustment parameters to said fixture 100 for the adjustment of the circuit breaker 101.

At the point of activation the device 101 is attached to an activation fixture 100. The serial number from the device along with customer information is then transmitted to an authentication server 101 which generates the adjustment parameters. This data is transmitted to the fixture. The fixture then adjusts the device's calibration means 102.

The authorization server 101 uses the devices serial number as the reference key to look up the device parameters in a data base. These parameters are transmitted in an encrypted manner using a public network interface 110 typically using TCP/IP as the transmission protocol.

In either aspect of this invention, If a counterfeit device is identified by either being in an activated or operational state before being placed in the activation fixture or during the activation method then the device can be de-activated & rendered safe & secure. The vendor will be notified locally & information relating to the location, vendor & date of sale can be sent to the manufacturer's validation service.

The third aspect of the invention is method of de-activating a circuit protection device 101 by adjusting said devices calibration means 102 causing the main contacts to open due to the effect of the position of the bimetal on the contact mechanism thus rendering the device un-usable.

The circuit protection device 101 is distributed to the point of sale in a de-activated & safe state. During the de-activation process if the circuit protection device 101 has been identified as a counterfeit device can be de-activated & made safe and details such as location of point of sale, vendor description, sale date etc can be transmitted to the original device manufacturer validation service or server 111 and is added to a database of identified counterfeit devices. A further option would be for a security feature added to the counterfeit device to prevent it being re-activated by manually adjusting the calibration screw 102 and a warning feature indicates locally that a counterfeit device has been detected