Patent Publication Number: US-2016233664-A1

Title: Automatic wiring board

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a non-provisional of US Application Serial No. 61/903,633, filed on Nov. 13, 2013. 
    
    
     BACKGROUND 
     The present disclosure relates generally to systems for dispensing hot melt adhesive. More particularly, the present disclosure relates to providing electrical power to heaters of a hot melt dispensing system. 
     Hot melt dispensing systems are typically used in manufacturing assembly lines to automatically disperse an adhesive used in the construction of packaging materials such as boxes, cartons and the like. Hot melt dispensing systems conventionally comprise a material tank, heating elements, a pump and a dispenser. Solid polymer pellets are melted in the tank using a heating element before being supplied to the dispenser by the pump. Because the melted pellets will re-solidify into solid form if permitted to cool, the melted pellets must be maintained at temperature from the tank to the dispenser. This typically requires placement of heating elements in the tank or melter, the pump and the dispenser, as well as heating any tubing or hoses that connect those components. 
     The heating elements of a hot melt system may be operated using alternating current (AC) power. Temperature controllers can be used to connect and disconnect electrical loads to AC input power such as a heating element in order to heat the hot melt adhesive to a temperature of about 350° F. The controllers can make use of a switch, such as a relay or a solid state switch connected between the source of input power and the load. A processor within the controller controls the operation of the switch to connect the load to input power when the load is to be operated and to disconnect the load under certain conditions, such as when the desired temperature has been exceeded. The available AC input power for operating heating elements of a hot melt system may be single-phase AC power, three-phase 230 volt AC power or three-phase 400 volt AC power and may be supplied by a two, three, or four wire electrical service. 
     SUMMARY 
     A system for supplying AC power to loads includes a terminal block, a voltage sensing circuit, an auto-wiring relay circuit, and a digital processor. The terminal block includes a plurality of terminals for connection to input AC power. The voltage sensing circuit senses AC voltage between the terminals of the terminal block. A plurality of controllers provides AC power to loads. The auto-wiring relay circuit selectively connects terminals of the terminal block to the plurality of controllers. The digital processor controls the auto-wiring relay circuit based upon the sensed AC voltages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an electrical block diagram of a system for providing AC power to selected heating elements of a hot melt dispensing system. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is an electrical block diagram of electrical power distribution system  10  of a hot melt dispensing system. System  10  includes automatic wiring board  12  (which includes terminal block  14 , power supply protection circuit  16 , indicator  18 , voltage sensing circuit  20 , microprocessor  22 , and auto-wiring circuit relay circuit  24 ), DC power supply  26 , display  28 , and controllers  30 ,  32 , and  34 . Controller  30  controls AC power to melter heater  36 , dispenser heaters  38  and  40 , and hose heaters  42  and  44 . Power controller  32  controls AC power to dispenser heaters  46  and  48  and hose heaters  50  and  52 . Controller  34  controls AC power supply to dispenser heaters  54  and  56  and hose heaters  58  and  60 . 
     Input AC power to automatic wiring board  12  to be supplied on two, three, or four wires which are connected to terminals T 1 -T 4  of terminal block  14 . Connection to earth ground is provided at terminal T 5  of terminal block  14 . 
     When single-phase AC power is supplied to automatic wiring board  12 , wires carrying the two-phase AC should be connected to terminals T 1  and T 2  of terminal block  14 . When three-phase  240  volt AC power is supplied, wires connecting the three-phases should be connected to terminals T 1 , T 2 , and T 3 . When three-phase  400  volt AC power is supplied, the wires for the three-phases should be connected to T 1 -T 3 , and neutral line should be connected to terminal T 4 . 
     Power supply protection circuit  16  is connected to terminals T 1  and T 2 . It receives single-phase AC power from terminals T 1  and T 2 . Power supply protection circuit  16  supplies protected power to DC power supply  26 . In the event of an over voltage condition, power supply protection circuit  16  protects DC power supply from damage due to high voltages. Power supply protection circuit  16  allows DC power supply to operate even during an over-voltage condition. Indicator  18  provides an indication of whether an over-voltage or an under voltage condition is present. 
     DC power supply  26  provides DC supply voltages to the circuitry control system  10 . These supply voltages are provided to voltage sensing circuit  20 , microprocessor  22 , auto-wiring relay circuit  24 , display  28 , and power controllers  30 ,  32 , and  34 . 
     Voltage sensing circuit  20  and microprocessor  22  monitor line voltages to identify whether single-phase or three-phase power is being supplied and whether  400  volt power is present. Voltage sensing circuit  20  is connected to each of terminals T 1 -T 4 . It provides an input to microprocessor  22  of the voltage between each combination of two terminals. Based upon the inputs from voltage sensing circuit  20 , microprocessor  22  identifies whether power is single-phase or three-phase, and whether the three-phase voltage is  400  volt power. It also determines whether the user has connected the input power wires to terminals T 1 -T 4  in the expected configuration, or in a different configuration than expected. Based upon this determination, microprocessor  22  provides control signals to auto-wiring relay circuit  24 . If voltage is too high, microprocessor  22  will not allow auto-wiring relay circuit  24  to connect power to any power controllers  30 ,  32 , and  34 . If voltage is too high, indicator  18 , which may be a red light emitting diode, will also turn on. If input voltage is too low, microprocessor  22  will not allow auto-wiring relay circuit  24  to connect controllers  30 ,  32 , and  34  to terminal block  14 , and will cause display  28  to display an error code. 
     If microprocessor  22  determines that the supplied AC power is single-phase, and the voltage is within a normal range, it will provide control signals to auto-wiring relay circuit  24  to connect each controller  30 ,  32 , and  34  to the same two terminals at which the single-phase AC power is present. Normally this will be terminals T 1  and T 2 . 
     If microprocessor  22  determines that voltage is within an acceptable range and  400  volt three-phase AC power is present, microprocessor  22  will provide control signals to auto-wiring relay circuit  24  to selectively connect controllers  30 ,  32 , and  34  to terminal block  14 . Three wires are provided to controller  30  from auto-wiring relay circuit  24 . Assuming that T 1 -T 3  receive the three-phases and T 4  is neutral, auto-wiring relay circuit  24  connects the three wires to terminal T 1 , terminal T 2 , and terminal T 4  (the neutral line). Controller  30  uses one phase of AC power to provide power to melter heater  36 . The other phase of AC power is used to power dispenser heaters  38  and  40  and hose heaters  42  and  44 . 
     Two wires are provided from auto-wiring relay circuit  24  to controller  32 . Auto-wiring relay circuit uses these two wires to connect controller  32  to terminals T 3  and T 4 . The single-phase power received by controller  32  is used to energize dispenser heaters  46  and  48  and hose heaters  50  and  52 . 
     Two wires are provided from auto-wiring relay circuit  24  to controller  34 . Auto-wiring relay circuit uses the two wires to connect terminals T 1  and T 4  through auto-wiring relay circuit  24  to power controller  34 . The single phase AC power is used by power controller  34  to energize dispenser heaters  54  and  56  and hose heaters  58  and  60 . 
     In the case of  230  volt three-phase AC power with no neutral wire, microprocessor  22  controls auto-wiring relay circuit in a similar manner, except that earth ground at terminal T 5  is used rather than a neutral wire at terminal T 4 . 
     In other words, microprocessor  22 , in conjunction with voltage sensing circuit  20 , reads the line voltages and determines the user supply of wiring configuration. If an acceptable configuration is detected, microprocessor  22  causes the appropriate relays within auto-wiring relay circuit  24  to close, so that controllers  30 ,  32 , and  34  are connected to the terminals that will supply the AC input power to the heaters. If the wiring is incorrect or if voltages are outside of a safe voltage range, microprocessor  22  causes the relays of auto-wiring relay circuit  24  to remain open. This protects the electronics of controllers  30 ,  32 , and  34  and the heaters that they are connected to from damage due to unsafe voltages. 
     Microprocessor  22  includes associated memory, such as flash memory, in order to log and track the wiring configuration detected and the measured voltages. This data can be made available for troubleshooting, such as through a USB data download. 
     Amperage allowed to each power controller  30 ,  32 , and  34  is calculated by microprocessor  22  and is divided up based upon the voltage configuration and the amperage setting on display screen  28 . The user can select a permitted amperage, and the voltage distribution needed is automatically determined by microprocessor  22  in conjunction with auto-wiring relay circuit  24 . 
     Control system  10 , and in particular automatic wiring board  12  provides a number of advantages. First, end user electrical insulation is reduced and simplified through simple connection of the power wires to the auto-wiring relay circuit  24 . Second, over voltage and mis-wiring protection is provided. Third, display  28  still powers up and shows an error when a mis-wired or over-voltage condition is present. Fourth, over voltage diagnostics are provided through data storage by microprocessor  22 . Fifth, the use of configurable jumpers for accommodating different AC input configurations is eliminated, because microprocessor  22  can detect the actual wiring configuration and control auto-wiring relay circuit  24  appropriately. Sixth, the use of preconfigured jumpers and the need for part numbers for those jumpers is eliminated. Seventh, customer voltage and wiring configurations are logged by microprocessor  22  and can be used for troubleshooting. 
     While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. For example, although the specific example described involves controllers supplying power to heating elements, in other embodiments other types of electrical loads can be supplied power. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.