Abstract:
An uninterruptible photosensing power controller for streetlight has a control box and a photosensing device. The control box has two sets of power cables and a socket. One set of power cables is connected to a utility pole and the other set of power cables is connected to a streetlight. The socket serves for the photosensing device to be plugged therein and fixed thereon. The photosensing device triggers the control box according to a luminance level of ambient light to control to supply a power from the utility pole to the streetlight. Since the photosensing device is directly fixed on the control box, the present invention simplifies the process and reduces the labor in installing a conventional power controller for streetlight.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention is related to a streetlight power controller, and more particularly to a streetlight power controller simplifying wiring procedure and ensuring to constantly turn on streetlight under thunder and lighting in the nighttime. 
         [0003]    2. Description of the Related Art 
         [0004]    With reference to  FIG. 7 , a conventional streetlight power controller has a control box  70  and a photosensing device  80 . The control box  70  has a power switch (not shown) mounted therein. The photosensing device  80  is electrically connected with the power switch inside the control box  80  by using power wires and sends a sensed luminance level of ambient light to the power controller inside the control box. 
         [0005]    The control box  70  has three power cables. Two of the power cables are connected with the power lines  61  (R, N) of a streetlight  60 , and the remaining one is connected with photosensing device  80 . Similarly, the photosensing device  80  has three power wires. One of the power wires is connected with the control box  70 . The rest of two power wires are connected with the power lines  51  (S, N) of a utility pole  50 . The control box  70  acquires the power from the power lines  51  of the utility pole through the photosensing device  80 . The power is not outputted to the control box  70  unless the luminance level of ambient light sensed by the photosensing device is low. The power switch in the control box further transmits the power to the power lines  61  of the streetlight  60  to turn on the streetlight  60 . Hence, when ambient light is bright, the control box  70  receives no power from the power lines  51  and the streetlight  60  goes off. 
         [0006]    To acquire the power of the power lines  51  of the utility pole  50 , the control box  70  must be connected with the power lines of the streetlight  60  and the photosensing device  80  must be connected with the power lines  51  of the utility pole  50 . Therefore, installation workers must carefully pay attention to the wiring correctness. Besides, for sake of being independent devices, the control box  70  and the photosensing device  80  need to be separately fixed on the streetlight pole with a fixing member. With reference to  FIG. 8 , the photosensing device  80  is fastened on a streetlight pole in collaboration with an inverted-L fixture and the control box  70  is separately fastened on a streetlight pole with screw. Accordingly, an installation worker must separately fix the control box  70  and the photosensing device  80  on the streetlight pole first, then connect the three power wires of the photosensing device with the power lines of the utility pole and the corresponding power cables of the control box  70 , and connect the remaining power cables of the control box  70  with the power lines of the streetlight  60 . All installation procedures are complicated, time consuming and do not allow to make mistake to the wiring connection. 
         [0007]    Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
       SUMMARY OF THE INVENTION 
       [0008]    A first objective of the present invention is to provide a photosensing power controller for streetlight capable of simplifying installation procedures. 
         [0009]    To achieve the foregoing objective, the photosensing power controller for streetlight has a control box and a photosensing device. 
         [0010]    The control box has a body, a socket, two sets of power cables and a power switch. The socket is mounted on the body. The two sets of power cables are mounted through the body. The power switch is mounted inside the body, is electrically connected with the socket and the two sets of power cables, and has a trigger terminal. 
         [0011]    The photosensing device is plugged in the socket of the control box, is electrically connected with the trigger terminal and one set of power cables through the socket, and triggers to switch the power switch in accordance with a luminance level of ambient light. 
         [0012]    The socket is mounted on the body and is directly and electrically connected with the power switch inside the control box. Installation workers only need to plug in the photosensing device on the control box in advance and fix the control box on the streetlight pole and further correctly connect the power cables of the control box with the power lines of the utility pole and the streetlight, thereby effectively reducing the procedures and labor of the installation. 
         [0013]    A second objective of the present invention is to provide an uninterruptible photosensing power controller for streetlight. 
         [0014]    The photosensing device of the uninterruptible photosensing power controller for streetlight has a relay. The relay has a first switch and a second switch. During nighttime, the first and second switches are switched on while the current from the utility pole flows through the first switch without going through the second switch connected with a resistor. When the first switch is damaged by a surge, the second switch provides a backup path to supply power to the streetlight through the first switching unit. The aforementioned power switch further has a second switching unit. The second switching unit has a transfer switch, a normally-open line and a normally-closed terminal. The transfer switch is connected with the trigger terminal and is activated by the first excitation coil of the power switch to selectively connect with the normally-open line or the normally-closed terminal. The control box further has a third switching unit. The third switching unit has a third excitation coil connected with the normally-open line of the second switching unit and a third switch connected between the two sets of power cables. 
         [0015]    When the first excitation coil of the power switch breaks down, the third switch is activated to switch on through the second switching unit and provide a path to supply power to the streetlight. Accordingly, even if subjected to thunder and lightening and faulty conditions, the present invention can be continuously triggered to light up the streetlight. 
         [0016]    Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a partially exploded view of a first embodiment of an uninterruptible photosensing power controller for streetlight in accordance with the present invention; 
           [0018]      FIG. 2  is a perspective view of the uninterruptible photosensing power controller for streetlight in  FIG. 1 ; 
           [0019]      FIG. 3  is a schematic view of the uninterruptible photosensing power controller for streetlight in  FIG. 1  connected with a utility pole and a streetlight; 
           [0020]      FIGS. 4A to 4C  are detailed circuit diagrams of the uninterruptible photosensing power controller for streetlight in  FIG. 1 ; 
           [0021]      FIG. 5  is a front view of a second embodiment of an uninterruptible photosensing power controller for streetlight in accordance with the present invention; 
           [0022]      FIGS. 6A to 6D  are detailed circuit diagrams of the uninterruptible photosensing power controller for streetlight in  FIG. 5 ; 
           [0023]      FIG. 7  is a schematic view of a conventional power controller for streetlight connected with a utility pole and a streetlight; and 
           [0024]      FIG. 8  is a side view of the conventional power controller for streetlight in  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    With reference to  FIGS. 1 to 3 , a first embodiment of an uninterruptible photosensing power controller for streetlight in accordance with the present invention has a control box  10  and a photosensing device  20 . 
         [0026]    The control box  10  has a body  11 , a socket  12 , two sets of power cables (S, R, N) and a power switch  30 . The socket  12  is mounted on a top of the body and the power cables (S, R, N) are mounted through the body  11 . In the first embodiment, the socket  12  has three plug holes  121 . One set of power cables (S, N) is adapted to connect with power lines  51  of a utility pole  50 . The other set of power cables (R, N) is adapted to connect with power lines of a streetlight. The socket  12  is electrically connected with a trigger terminal (I/P) of the power switch  30  and the set of power cables (S, R, N) connected to the streetlight  60 . 
         [0027]    The photosensing device  20  is plugged in the socket  12  of the control box  10  and is electrically connected with the trigger terminal (I/P) of the power switch  30  through the socket  12  and triggers the power switch  30  to switch on or off in accordance with a luminance level of ambient light. In the first embodiment, the photosensing device  20  has three blades  201  to correspond to the three plug holes  121  and the three blades  201  are plugged in the three plug holes  121  of the socket  12 . 
         [0028]    With reference to  FIG. 4 , the photosensing device  20  has a relay and a photovaristor  21 . The relay has an excitation coil  212 , a first switch S 1  and a second switch S 2 . The first switch S 1  and the second switch S 2  are parallelly connected between the power line S connected to the utility pole and the excitation coil  212  and connected with the trigger terminal I/P of the power switch  30 . The second switch S 2  is serially connected with a resistor R. The photovaristor  21  is serially connected between the S line of the set of power cable connected to the utility pole and the N line of the set of power cable connected to the streetlight  60  through a resistor  211  and the excitation coil  212  of the relay. 
         [0029]    The power switch  30  has a first switching unit  32  and a first excitation coil  31 . The first switching unit  32  is connected across the S line of the set of power cable connected to the utility pole and the R line of the set of power cable connected to the streetlight  60 . One end of the first excitation coil  31  is connected with the trigger terminal I/P and is connected with the first switch S 1  and the second switch S 2  of the photosensing device  20 . The first switching unit  32  is switched on by a current outputted from the first switch S 1  or the second switch S 2  and flowing through the first excitation coil  31 . 
         [0030]    During daytime, the photovaristor  21  has a low resistance value (below 50Ω) due to the bright luminance. The excitation coil  212  of the relay is induced so that the first switch S 1  and the second switch S 2  switch off. Hence, the set of power cable  51  of the utility pole  50  is disconnected from the first switch S 1  and the second switch S 2 . Meanwhile, the first excitation coil  31  of the power switch  30  has no current flowing in, the first switching unit  32  switches off, and the set of power cable connected to the streetlights  60  is disconnected. As a result, the streetlights  60  go off. 
         [0031]    With reference to  FIG. 4B , during nighttime, the photovaristor  21  has a high resistance value (1MΩ) due to the deficient luminance. The first switch S 1  and the second switch S 2  of the relay simultaneously switch on. As the second switch is serially connected with the resistor R, a current from the utility pole flows to the trigger terminal I/P of the power switch  30  through the first switch S 1  instead of the second switch S 2 . The first excitation coil  31  of the power switch then activates the first switching unit  32  to switch on to connect to the power cable connected to the streetlight  60 . The power of the utility pole is outputted to the streetlight and the streetlight turns on. 
         [0032]    With reference to  FIG. 4C , when the current of the power of the utility pole  50  increases due to a thunder and lightening in the nighttime, the first switch S 1  breaks down but the second switch S 2  remains to be on as an alternative power input path. A current flowing through the first excitation coil  31  continuously activates the first switching unit  32  to switch on. Therefore, the power from the utility pole is outputted to the streetlights  60  through the first switching unit  32 . 
         [0033]    With reference to  FIGS. 5 and 6A , a second embodiment of an uninterruptible photosensing power controller for streetlight in accordance with the present invention has a photosensing device  20  and a control box  10   a.    
         [0034]    The photosensing device  20  is the same as that of the first embodiment. The control box  10   a  is similar to that of the first embodiment except that the power device  30   a  further has a second switching unit  33  and the control box  10   a  further has an third switching unit  40 . The second switching unit  33  has a transfer switch  331 , a normally-open terminal NO and a normally-closed terminal NC. The transfer switch  331  is also activated by the first excitation coil  31  of the power switch  30   a  to selectively connect with the normally-open terminal NO or the normally-closed terminal NC. The third switching unit  40  has a third excitation coil  41  and a third switch  42 . One end of the third excitation coil  41  is connected with the normally-open terminal NO of the second switching unit  33 , and the other end is connected with the N line of the set of power cable connected to the streetlight  60 . The third switch  42  is connected across the S line of the set of power cable connected to the utility pole and the R line of the set of power cable connected to the streetlight  60 . 
         [0035]    With reference to  FIGS. 3 and 6A , the second embodiment of the uninterruptible photosensing power controller for streetlight is operated in the daytime. Because the resistance value of the photovaristor  21  is low, the power of the utility pole  50  is not inputted to the first excitation coil  31  of the power switch  30   a , the first switching unit  32  is not switched on, and the transfer switch  331  of the second switching unit  33  is connected with the normally-open line NO. Accordingly, the streetlights  60  go off. 
         [0036]    With reference to  FIG. 6B , during nighttime, the resistance value of the photovaristor  31  increases and the current of the utility pole  50  is inputted to the first excitation coil  31  of the power switch  30   a  through the first switch S 1 . Thus, the first switching unit  32  is switched on, the power from the utility pole  50  is outputted to the streetlights  60 , and the streetlights turn on. Meanwhile, the transfer switch  331  of the second switching unit  33  is activated by the first excitation coil  31  to connect with the normally-closed terminal NC and protect the power through the first switch from flowing in the streetlights  60  through the third switch  40 , so that the second switching unit can be continuously switched on. 
         [0037]    With reference to  FIG. 6C , when the power of the utility pole  50  encounters a surge due to thunder and lightening and the first switch S 1  breaks down, the second switch S 2  remains intact due to the resistor R and switches on, and the transfer switch  331  of the second switching unit  33  is activated by the first excitation coil  31  to connect with the normally-closed terminal NC. Meanwhile, the current of the utility pole  50  is outputted to the first excitation coil  31  of the power switch  30   a  through the second switch S 2 , and the first switching unit  32  is switched on. Therefore, the power of the utility pole  50  is outputted to the streetlight  60  through the first switching unit  32 , and the streetlight turns on. As the transfer switch  331  is connected with the normally-closed terminal NC, the power of the utility pole  50  is protected from flowing in the streetlight  60  through the third switch  40  so that the first switching unit  32  can be continuously switched on and the transfer switch  331  of the second switching unit  33  can be continuously connected with the normally-closed terminal NC. 
         [0038]    With reference to  FIG. 6D , when the first excitation coil  31  of the power switch  30   a  breaks down, the transfer switch  331  is connected with the normally-open terminal NO for sake of the unavailable first extraction coil  31 . When the power of the utility pole  50  is outputted to the third excitation coil  41  through the first switch S 1  and the second switching unit  33 , the third switch  42  is activated by the third excitation coil  41  to switch on, the power from the utility pole is outputted to the streetlights  60  through the third switch  42 , and the streetlights  60  turn on. 
         [0039]    Given the socket  12  mounted on the control box  10  and electrically connected with the power switch  30  inside the control box  10 , the photosensing device  20  can be directly plugged in and fixed on the control box  10 , and electrically connected with the power switch  30  inside the control box  10 . Consequently, installation workers only need to mount the photosensing device  20  on the control box  10  beforehand and fix the control box on the streetlight pole. Furthermore, installation workers just need to correctly connect the power cables of the control box  10  with the power lines of the utility pole  50  and the streetlight  60 , thereby effectively simplifying the process and reducing labor of the installation. Moreover, the first switch S 1  of the relay inside the photosensing device  20  is parallelly connected with the second switch S 2  serially connected with a resistor. After the first switch S 1  is damaged by a surge current, the second switch S 2  provides a backup path to supply power to the streetlight  60  through the first switching unit  32 . When the first excitation coil  31  of the power switch  30   a  breaks down, the power from the utility pole  50  flowing through the normally-open terminal NO of the second switching unit  33  activates the third switch  40  to switch on and supplies power to the streetlights  60  through the third switch  40 . Accordingly, even if subjected to thunder and lightening and faulty conditions, the present invention can be continuously lighted up to safeguard passersby. 
         [0040]    Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.