Abstract:
The method is for testing an electrical component. The sender unit  12  may be applied to an electrical plug  24  that has a first line  28,  a second line  32  and a ground line  36.  It is determined which of the lines  28, 32, 36  that has a voltage potential relative to the surrounding. The phase configuration of the electrical plug  24  may be determined. The unit  14  is applied to a remote electrical unit and the sender sends a synchronization signal  41  to the receiver unit  14  that starts a counter providing a measurement of the time difference between corresponding phase positions of the alternating current of the plug  24  and that of the remote electrical unit. This time difference can then be converted to a phase difference value. The system may also be used to identify a specific fuse that is associated with the plug and for testing ground fault interrupting devices.

Description:
PRIOR APPLICATION  
       [0001]     This is a continuation-in-part application of U.S. patent application Ser. No. 10/250,182 filed on Jun. 10, 2003. 
     
    
     FIELD OF INVENTION  
       [0002]     The method and device system of the present invention relates to the testing of electrical components such as electrical wires, plugs and fuses.  
       BACKGROUND OF INVENTION  
       [0003]     Electricians and others often need to determine the configuration of electrical plugs and wires in electrical systems such as determining the phase or phases of a plug and the configuration of a fuse box. For example, electricians sometimes need to determine which phases the fuses are associated with and sometimes which particular fuse that is connected to a particular electrical plug. The currently used methods are not only quite cumbersome but also dangerous particularly if it is not possible to turn off the electrical system during the testing procedure. For example, when the electrical system cannot be shut off, some electricians short-circuit the plugs to trigger the fuses to determine which fuse is connected to which plug. This method can create fires and injuries to the electrician. It may also damage the devices that are connected to the electrical system. The currently available testing devices are sensitive to how the testing device is connected to the electrical plug. The voltage phase and/or the reference phase must be in the right place to make the tester show the correct result. The displayed result of the phase configuration often depends on how the testing device is turned when it was plugged in. If the testing device is turned upside down a different result is shown compared to the situation when the upside is turn upwardly. It may not be able to detect the situation when one of the wires carries a current but there is no ground or zero-reference component. It is also difficult to test ground fault devices that are used to detect ground faults to make sure the devices are triggered within a certain permitted time period. Despite many efforts, the currently available devices and methods are not satisfactory. There is a need for a reliable and effective device and method that may be used to accurately and safely determine the configuration of electrical systems while the system is in full operation.  
       SUMMARY OF INVENTION  
       [0004]     The system of the present invention provides a solution to the above-outlined problems. More particularly, the method of the present invention is for testing an electrical component. The sender unit may be applied to an electrical plug that has a first line, a second line and a ground line. It is determined if the first line, the second line or the ground line has a voltage potential relative to the surrounding. The sender unit is connected to a remote receiver unit. The phase configuration of the electrical plug may be determined. The unit is applied to a remote electrical unit and the sender sends a synchronization signal to the receiver unit that starts a counter to determine if the remote electrical unit has a phase that is different from the plug by analyzing alternating voltage of the remote electrical unit. The system may also be used to identify a specific fuse that is associated with the plug and for testing ground fault interrupting devices. 
     
    
     BRIEF DESCRIPTION OF DRAWING  
       [0005]      FIG. 1  is a schematic view of the device system of the present invention;  
         [0006]      FIG. 2  is a schematic view of a reference phase voltage and synchronization signal at a transmitter unit; and  
         [0007]      FIG. 3  is a schematic view of an unknown phase voltage at a receiver unit and the synchronization signal received from the transmitter unit. 
     
    
     DETAILED DESCRIPTION  
       [0008]     With reference to  FIG. 1 , the device system  10  has a transmitter unit  12  and a receiver unit  14  that are in communication such as by, for example, radio signals. The sender unit  12  may have protrusions or connectors  16 ,  17 ,  18  that fit into openings  20 ,  21 ,  22 , respectively, of an electrical plug  24 . The plug  24  has a first wire  26  connected to a first line  28  and a second wire  30  connected to a second line  32  and a ground wire  34  connected to a ground line  36  of a power supply system  38 . An important feature of the system  10  of the present invention is that it is not necessary to turn off the electrical system  38  to fully determine the configuration of and other information about the live plug  24 . Preferably, the system  10  is used to test single-phase systems but can also be used for multiple phase systems, if so desired.  
         [0009]     In operation, the sender  12  is connected to or plugged into the live plug  24  and turned on. The sender  12  may first determine if there is any voltage present at the connectors of the plug  24  without being in physical contact with the wires and before the microprocessor  52  is activated. At this point, it is not necessary to use the receiver  14 . When the sender unit  12  has determined that there is a voltage in at least one of the wires of the plug  24 , the microprocessor  52  may be activated to analyze the configuration of the plug  24 . The sender  12  may send information signals  40 , such as radio signals, to the receiver  14  or if the sender  12  has a processor, start analyzing the configuration of the phase of the plug. If the information is sent to the receiver  14 , the receiver  14  receives the signals  40  and uses the information in the signals  40  to determine the status and configuration of the plug  24  by activating a microprocessor  53 . The calculations may also be performed in the transmitter unit so that merely the result is sent to the receiver unit.  
         [0010]     The processors may be used to calculate and determine the configuration of the plug  24  such as determining which component is the ground, the zero-reference and the voltage component. For example, once it has been determined that there is a voltage potential in the plug  24 , the microprocessor  52  analyzes each of the wires  26 ,  30 ,  34  connected to the plug  24  and determines the configuration of the wires. If the initial analysis indicates that there is a voltage in the wire  30 , the processor  52  may start the analysis based on this information. The processor  52  may check that there is a proper voltage potential between the wire  30  and the wire  26  and between the wire  30  and the ground  34 . If there is no resulting voltage difference, the plug  24  may lack a zero-reference wire  26  and/or a ground  34 . It may also test the ground  34  and the wire  26  to make sure there is no unacceptable resistance therebetween by applying a small current therebetween and test the resulting voltage.  
         [0011]     It is important to test all three components and not just a pair in case the plug has no zero-reference component or ground. By measuring only two components, the user can only determine that there is a voltage difference but not whether the plug lacks the ground or zero-reference component and other vital information. For example, the plug may carry two phases but the ground and/or the zero-reference component is not properly connected.  
         [0012]     As indicated earlier, the sender  12  may send the information signal  40  to the receiver  14 . Upon receipt of the signal  40  from the sender, the result may be displayed in the display  48  of the receiver  14 . For example, the signal  40  may include information about the voltage and/or frequency. The shape of the signal may also be continuously displayed. Of course, the display  48  may be disposed on the sender  12  also. As discussed below, the sender  12  may continuously send a synchronization pulse  41  to the receiver  14  that the receiver  14  may use to analyze the relationship between the plug  24  and remotely located wires, plugs and fuses.  
         [0013]     As indicated above, the system  10  may also be used to determine phase configurations. The sender  12  sends the synchronization signals  41  to the receiver  14  when the wave curve of the alternating voltage is, for example, at the peak. The receiver  14  receives the signals  41  and starts a time counter as the probe  43  of the receiver  14  is applied to a remote wire or fuse to be investigated. In this way, the peak values of the wave curve of the remote wire and the position of the peak values of the plug  24  contained in the signals  41  are compared to determine if the voltage of the remote wire is in the same phase as the voltage of the plug  24 . Depending upon how long the counter has counted, i.e. the time, until it receives the peak value from the remote wire, it can be determined what the phase relationship is between the remote wire and the reference wire at the sender  12 . If the phase of the remote wire is  120  degrees ahead or behind the alternating voltage of the plug  24 , information about the phase relationship between the two voltages is displayed in the display  48 . The system  10  may also be used to determine if the three phases of a three-phase plug exist and that they are correctly connected so that there is  120  degrees difference between the three phases and that the order is correct.  
         [0014]     It is possible to determine if the remote wire, a single fuse or a group of fuses belong to the same phase as the plug  24 . The fuses in an electrical box are sometimes split up evenly between the three phases so that about ⅔ of all the fuses may belong to one of the other two phases. The system  10  may be used to determine and make sure that all the phases of the entire electrical system correctly reach the fuse box so that the correct fuses are connected to the right phases.  
         [0015]     A third important function of the system  10  is to determine which particular electrical component, for example a fuse, ciruit breaker or wire, disposed in a remote site or part of the installation, is connected to the plug  24 . If the electrical component is a fuse or circuit breaker, the proper connection can be tested without having to disengage the component. It is also possible to determine, with the help of the phase finding feature of the receiver  14 , which plugs are connected to the same component to ensure it is safe to disengage the particular component without damaging other equipment connected to the same circuit or phase.  
         [0016]     More particularly, the sender  12  at the plug  24  generates a small alternating current. This current may be modulated at a very high frequency that is easy for the receiver  14  to identify. Preferably, the frequency should be very different from 50-60 Hz or near multiples thereof because those frequencies are often used for conventional alternating current. Typically, a frequency of 1-100 kHz or any other suitable frequency may be used. The receiver  14  at the component  44  detects a magnetic field  80  that are created as a result of the small current. The magnetic field, as opposed to the electric field or voltage variations, may not spread to other components because only the component that carries the particular current will generate the magnetic field. A component  45  may be surrounded by a different magnetic field  81 . In general, the sender  12  may also send out an identification signal so that the receiver  14  can distinguish the signals from the sender  12  from other senders that may be in operation in the vicinity. The use of the identification signal may be used for all the applications of the system.  
         [0017]     In practice, the receiver  14  has the sensor  42  disposed in a testing probe  43  that may be held close to an electrical component such as a fuse  44  or a wire  46  to determine if the plug  24  is connected to the fuse  44  or if the plug  24  is connected to the same phase as the wire  46  or if the phase of the wire  46  is 120 degrees ahead or behind the phase of the plug  24 . The receiver  14  has the display  48  that indicates the correct fuse or wire and shows the voltage and frequency of the plug  24  at the time of the testing. By using radio communication, the user may determine if the voltage in the plug  24  is present although a fuse  44  or circuit breaker has been disconnected. The sender  12  has a built in power supply  50 , such as a battery, so that the sender  12  functions even if the plug  24  has no voltage. For example, if the fuse  44  is connected to the plug  24  and the fuse  44  is disconnected to cut off the current to the plug  24 , the sender  12  may still send information to the receiver  14 .  
         [0018]     A fourth important function is that the system  10  may also be used to test and make sure that residual current detectors  51  are functioning properly and that the detectors turn off the electricity within a permitted time period such as  200  milliseconds or any other time limit. The system  10  may also be used to determine which particular residual current detector  51  that is connected to the plug  24  by analyzing the phases, as outlined above. To test the functionality of the residual current detector, the sender  12  may apply a very small controlled faulty current between the phase and the ground, but not the zero-reference wire, of the plug, and the receiver  14  measures the time it takes until the detector  51  releases. The receiver  14  may transmit a trigger signal  47  to the sender  12  to apply the current at the source plug  24  and the time it takes before the residual current detector  51  is released is measured.  
         [0019]     The determination of a reference voltage value in a system  100  is described in more detail below and shown in  FIG. 2 . In the following case it is assumed that the voltages that are tested are sinusoidal or near sinusoidal. The principles of the present invention will however work with any curve form that is periodical and with a basic frequency in the range for which the system is designed, assuming the different phases have similar waveforms.  
         [0020]     A reference time, that may represent the time for reaching a peak value or any reference voltage value, may be calculated by starting a counter from the time it takes from the first time (t 1 ) at the voltage level  108   a  of a reference phase voltage  110  (while in positive slope) until a time (t 2 ) is reached of the same reference phase voltage (V 1 ) at a second voltage level  112 , that is identical to the voltage level  108   a,  is reached again (while in negative slope) and the counter stops. In other words, the counter counts while the reference phase voltage is greater than the reference phase voltage at the first voltage level  108 . It is then assumed that the reference value (i.e. peak value of a sinusoidal curve) is in the middle of the first time (t 1 ) at the voltage level  108  and the second time (t 2 ) at the second voltage level  112 . The time difference between the first time (t 1 ) and the second time (t 2 ) has the total length ( 2 L). A length (L) of the synchronization pulse  114  is then adjusted and determined so that it is half of the time difference between the first time (t 1 ) and second time (t 2 ).  
         [0021]     The synchronization pulse  114  is sent at the voltage level  108   b  at a third time (t 3 ) of a second cycle  116  and the length (L) of the pulse  114  is half of the time between the first time (t 1 ) and second time (t 2 ). In this way, the synchronization pulse ends at a fourth time (t 4 ) at a reference point or peak  118  of the reference phase voltage  110 .  
         [0022]     The determination of the corresponding reference point, i.e. peak value in time, that represents the corresponding reference point or peak value  120  of an unknown phase voltage  122  is carried out in a similar way. As an illustrative example, the peak value  120  is selected as the reference point although another reference point on the unknown phase voltage  122  and the reference phase voltage  110  may be selected.  
         [0023]     As best shown in  FIG. 3 , the time to the reference value (i.e. the peak value of a sinusoidal curve) of the unknown phase  122  may be calculated by starting a counter at the termination of the synchronization pulse at a fifth time (t 5 ). The fifth time (t 5 ) may represent the time of a reference point, such as the peak value at the time (t 4 ) or a later time of a subsequent peak value, of the periodical reference phase voltage  110 . A time (t 6 ) is read at the voltage level  130  of the unknown phase  122  (while in positive slope) until a subsequent time (t 7 ) is reached of the same reference phase voltage (V 2 ) at a second voltage level  132 , that is identical to the voltage level  130 , is reached again (while in negative slope) and the counter stops. The counter counts while the voltage of the unknown phase  122  is greater than the reference phase voltage at the voltage level  132 . It is then again assumed that the reference value (i.e. the peak value of a sinusoidal unknown phase curve) is in the middle of the time (t 6 ) at the voltage level  130  and the time (t 7 ) at the second voltage level  132 .  
         [0024]     The time difference between the time t 6  and the time t 7  is  2 P. The time from termination of the synchronization pulse at the time (t 5 ) and the mean value of the time between the time (t 6 ) and the time (t 7 ) is then calculated to determine the phase difference between the reference voltage phase  110  and the unknown voltage phase  122 .  
         [0025]     While the present invention has been described in accordance with preferred compositions and embodiments, it is to be understood that certain substitutions and alterations may be made thereto without departing from the spirit and scope of the following claims.