DC Ground Fault Location                                                       
                                             
                                                   GFAL - A and GFAL-B

                                                          User's Manual                                     By Samco Engineering  

              
          Table of contents
          Sections                                                            

        1.0      Introduction                                                                                                                  
   
        2.0     GFAL- A, Description                                                     

        3.0    GFAL- A, Display meters                                                

        4.0     GFAL- A, Control switches                                             

        5.0    GFAL- A, Field applications                                             

        6.0    GFAL- A, Specifications                                                     

        7.0    GFAL- A, Appendix A,  Battery Pack Maintenance            

        8.0    GFAL- A, Appendix B, Special application
                  Find the value of the fault resistance from each polarity                                                       

        9.0    GFAL-B, DC Ground Fault Tracker unit                       

        10.0    GFAL- B, Introduction                                                  

        11.0    GFAL- B, Applications                                            

   
        12.0    GFAL- B, Specifications         

        13.0    Appendix C,  Battery Pack Maintenance

                                                         
        14.0    Appendix D, GFAL-A/B Method "Locating DC ground faults"                                              
       
        15.0    Locating DC ground faults    

        
16.0   Warranty and Contact Information                                

        1.0 –   Introduction

                  Hardware

        The GFAL-A/B method to indicate and locate DC ground faults is made up of two instruments, the GFAL-A (Fig.1)
        is the interrupter unit, also this unit can be use on its own as a DC ground fault analyzer instrument, it connect to the DC
        distribution system with a 3 cable harness.


        The GFAL-B (Fig.2) is the tracker unit, it has a removable sensor that wrap around the conductors for troubleshooting purpose,
        this unit need the GFAL-A to locate DC ground faults.


            Present methodology to indicate DC ground faults


        The existence of a DC ground fault in a multi-feeder DC distribution system is commonly indicated by voltmeters. 
        The voltmeters are attached to the DC distribution system and will indicate ground faults; however, if a second ground fault
        with an equivalent resistance is present on the opposite polarity the voltage equilibrium with respect to ground is restore and
        the voltmeters will fail to indicate the ground faults.


        There are many other variations of this voltage imbalance measurements procedure, a few examples are: the replacement of
        voltmeters with light bulbs, ground fault detector/alarm relays, or a current meter connected at the center point of a voltage divider.


        The major problem with all the cited DC ground fault indication methods is that they use the voltage imbalance technology for indication,
        consequently, as mentioned earlier, these methods and instruments will have erroneous or no indication at all on multiple ground faults
        if those faults are located on opposite polarity.


        After the DC ground fault it has been detected by the monitor equipment, the fault has to be located in order to correct the problem.


        To find the location of these faults is a very difficult task without having the proper method, instrument and personal training in the art
        of locating DC ground faults.


         The penalty for not locating these faults in a timely manner could include a complete system shutdown costing hundred of thousand
        of dollars per day.

                                   
                     GFAL- A, DC Ground fault Analyzer unit

   
           Samco Engineering  GFAL-A
                                                                          Fig 1
  
        2.0 – GFAL- A, Description

        There are 2 Input Connectors

        1) CHARGER
        Input connector for the 12-18 VDC adapter, the center is the positive polarity
        The Green LED next to the connector will light up when the charging adapter is connected.
        The Red LED BATT LOW will light up when the battery is low and need to be charge.

        2) PROBE

        Input connector for the positive and negative polarity and site ground of the DC system under test.


        3.0 – GFAL- A, Display meters

        There are 2 display meters
 

        1) VOLTS

        The voltmeter displays the AC or DC voltage from the point of connections of the PROBE.

        Remarks

        The voltmeter display is in volts e.g. 002 display representing 2 volts disregard the zeros on the left side.

        To test for AC voltages on the distribution system the Red cable has to be connected

        2) MILLIAMPS

        Display the pseudo fault current from the PROBE point of contact trough the Instrument
        Remark

        The display is in milliamps, 02.0 mA represent 2.0 mA, disregard the zeros on the left side

        4.0 – GFAL- A, Control switches


          FUNCTION SELECT,
        6 position switch

           Remark
         With the FUNCTION SELECT Switch in positions 2-6 the green LED at the upper left corner of the FUNCTION SELECT        
        switch box should light up, (otherwise the internal battery of the Instrument is discharged or disable).

     
        1) OFF  

        In this position, the GFAL-A instrument is turn off.
       
Remark
       
The battery charge function can be performed (and is recommended) with the FUNCTION SELECT switch in the OFF position


        2) AC CONT

        Read the AC voltage from the DC system under test with respect to site ground.
         
Remark
        To perform this test, the red (+) cable has to be attached to the system under test.


        3) POS/NEG
        Read the voltage between the Positive Polarity with respect to the Negative Polarity of the DC system under test.

        Remark
        To perform this test, the red (+), the black (-) and the green (connected to site ground) cables are to be attached to the system under test.


        4) POS/GND

        Read the DC voltage between the Positive Polarity with respect to site ground of the system under test.
       
Remark
        Also, enable the POS POLARITY TO GND and the NEG POLARITY TO GND switches.                                                                                                               
         
        5) NEG/GND
  Read the DC voltage between the Negative Polarity with respect to site ground of the system under test.
       
Remark
        Also, enable the POS POLARITY TO GND and the NEG POLARITY TO GND switches.

         
        6)
LOC
        Initiate the interrupter function of the GFAL-A. Also, enable the POS POLARITY TO GND and the NEG POLARITY TO GND switches.
        The cycle has two stages, for 6 seconds the ground fault circuit from the negative polarity close and for 6 seconds the ground fault circuit is open.
        Them
for 6 seconds the ground fault circuit from the positive polarity close (when the negative polarity open) and for 6 seconds the ground fault circuit is open,
        when the negative polarity close, them the cycle will repeat
            Remark
         When the LOC position is selected the blue LED at the upper left corner of the LOC FLASH PULSE will be on for about 1 second
         and will repeat every 12 seconds.
       
        POS POLARITY TO GND
        7 position switch

        1)    OFF
            Disconnect all the pseudo fault resistances from the positive polarity with respect to site ground

        2)     80    
            Insert a 80 Kohm resistor from the 
positive polarity to ground
        3)     60    
            Insert a 60 Kohm resistor from the 
positive polarity to ground  
        4)     40    
            Insert a 40 Kohm resistor from the 
positive polarity to ground
        5)     20    
            Insert a 20 Kohm resistor from the 
positive polarity to ground
        6)     10    
            Insert a 10 Kohm resistor from the 
positive polarity to ground
        7)     5    
            Insert a 5 Kohm resistor from the 
positive polarity to ground

          Remark
        IF the FUNCTION SELECT switch is at position POS/GND or NEG/GND and the POS POLARITY TO GND switch is at any
        position among 2-7, the red LED in the box POS POLARITY TO GND will light up, indicating that a pseudo fault resistance
        from the GFAL-A is connected to the positive polarity of the distribution system with respect to site ground.


        NEG POLARITY TO GND

        7 position switch

          1)     OFF
            Disconnect all the pseudo fault resistances from the negative polarity with respect to site ground
   
        2)     80    
            Insert a 80 Kohm resistor from the negative polarity to ground

        3)     60    
            Insert a 60 Kohm resistor from the negative polarity to ground
  
        4)     40    
            Insert a 40 Kohm resistor from the negative polarity to ground

        5)     20    
            Insert a 20 Kohm resistor from the negative polarity to ground

        6)     10    
            Insert a 10 Kohm resistor from the negative polarity to ground

        7)     5   
            Insert a 5 Kohm resistor from the negative polarity to ground


           Remark  
        IF the FUNCTION SELECT switch is at position POS/GND or NEG/GND and the NEG POLARITY TO GND switch is at any
        position among 2-7, the red LED in the box NEG POLARITY TO GND will light up, indicating that a pseudo fault resistance
       
from the GFAL-A is connected to the negative polarity of the distribution system with respect to site ground.
       
          LOC FLASH PULSE
        3 position momentary switch, enable only when the FUNCTION SELECT switch is on the LOC position 
     
          This switch increase (FAST) or decrease (SLOW) momentarily the frequency of the PULSE TRACKER to synchronize the
        GFAL-A with the GFAL-B

          At the center position the switch is off
               
        5.0 – GFAL- A, Field applications

        Application # 1     AC voltage on DC distribution systems
       
Test
        Directly read AC voltage respect to site ground on DC distribution systems
       
Used for
        Verify the amount of AC Voltage that exists between the DC distribution system with respect to site ground.

        It also will indicate the presence of DC ground fault spikes in the DC distribution systems.

        Caution:    “Phantom” Earth Grounds

          A path to ground through UPS can result in extremely hazardous AC voltages being present between the DC system
        and the grounded racks and switchgear enclosures. 

          This condition in case of person come in direct contact with any conductor of the DC distribution system can result in a fatal shot.
       
        Application # 2    
DC Voltage between polarities
        Test

        Directly read the DC voltage between the positive polarity of a DC distribution system with respect to the negative polarity.

        Used for    
        This test will verify any site voltage indication attached to the DC distribution system.


        Application # 3    Positive voltage respect to site ground
          
Test
        Directly read the DC voltage between the positive polarity with respect to site ground
       
Used for
        This test will verify any site voltmeter(s) attached to the DC distribution system, and there is not crossover contamination  
        between two battery assembles of independent systems.

        Application # 4     Negative voltage respect to site Gnd.
        Test
        Directly read the DC voltage between the negative polarity respect to site ground.
        Used for
        This test will verify any site voltmeter(s) attached to the DC distribution system, and there is not crossover
        contamination between two battery of independent systems.


        Application # 5    DC alarm trip points of operation
        Test
        By introducing a variable resistance between a polarity of a DC system and site ground.
        Used for
        It will test the operation and response of the DC alarm system.
          If the site DC Alarm it is properly working should trip when the introduced resistance is below the set point
        needed to trip the alarm.

        Disconnected, out of commission and out of specifications site DC alarms are quickly exposed by the
        GFAL-A instrument, if the alarm does not respond when the test resistance value is below the trip point
        specify for the alarm.


        Application # 6       Finding the value of fault resistance from each polarity of a battery distribution system
                                       with respect to site ground.

        Test
        By performing two field tests, the second test with the help of a pseudo resistor from the GFAL-A unit connected between
        the DC system with respect to site ground and the use of calculations, the value of the fault resistance from each polarity with
        respect to site ground could be found.

        Used for
        The voltage imbalance readings on DC system are normally performed by voltmeter(s).  The voltmeter(s) data can not give
        information on the actual value of the fault resistance that exists from each polarity respect to site ground. 

        One resistance respect to ground in one polarity cancels the effect (voltage imbalance cancellation) from another resistance
        respect to ground over the other polarity.

        Note
        To know how to perform this method use Appendix B


        Application # 7     Extreme DC system voltages respect to site ground
        Test
         The GFAL-A can determent if the readings of 0.0 VDC from one polarity, and full DC voltage reading from the other polarity,
       with respect to site ground is the result of a short circuit of one of the polarity with respect to ground, an instrument failure
        or is the result of an open connection from the site ground detector unit. 

         Used for
        When a short circuit occurs in a DC distribution system the voltage imbalance readings are: full battery voltage from the polarity
          without the short circuit and near 0.0 VDC from the polarity with the short circuit.     
        When one side of a relay on a DC alarm system fails open or a resistor on a voltage divider fails open, the voltage imbalance
        readings are; full battery voltage from the polarity with the open resistance and near 0.0 VDC from the other polarity.

        Remark
        The point is that an open connection and a short circuit to ground will yield the similar voltage readings from the DC system with
        respect to site ground.

          The reliability of a DC System having an open relay or resistor is totally opposite to the reliability of the same system having a short
        circuit from one polarity to ground.


        Application # 8      Predict Maintenance Program
        Test
        Performing periodic readings and creating data base files from both polarities of a DC System.
        Important data to collect are: DC Voltage between polarities and respect to site ground, AC contamination in the DC system,
        DC ground fault resistance from each polarity and DC Alarm system response and operation.

        Used for
        The base line readings from a good working DC system are a very important data to have when grounds fault materialize.

        Application # 9      Miscellaneous Applications         
           Help identify and quantified DC ground faults on DC systems.                   
        Can create balance or imbalance loads respect to site ground on a DC systems up to 6 different values, from 5 K Ohm to 80 K Ohm
          With the help of a DC external power source can analyze de-energize circuits.
        With the help of a decade resistor box can increase the input impedance of the Instrument respect to site ground.
        Useful to train technical people on DC Ground fault theory and troubleshooting.

        6.0 – GFAL- A, Specifications
        Operating DC range                  12 to 270 VDC

        Impedance Range                     5 K to 10 M Ohm (5% accuracy)
        Switching pseudo grounds         By opto-isolation, “Cold Switching”
        Accuracy (full scale)                 Minimum 5%
        Environmental                          30 to 125 Degrees F
        Power source input                  12-18 VDC
        Internal battery operation          24 hr (Rechargeable)
        Display (volts and mA)             2, 3 Digit LCD
          Dimensions                              12” x 7.5” x 11” 
        Weight                                     6 Lb.
        Case (2 colors)                         Gray and yellow
        Warranty                                 1 yr. Parts and Labor


        7.0 – GFAL- A, Appendix A, Battery Pack Maintenance
        The internal battery assembly consists of four AA Nickel Metal Hydride (NiMH) cells.
        The voltage of the pack is approximate 5.6 VDC at full charge.

         Charging the Pack

          If the red LED BATT LOW turns on is time to recharge the battery pack.
        A battery charging adapter unit is furnished with the GFAL-A, the adapter has a nominal output voltage of 12-18 VDC and
        a current capacity no less of 500 mA.

        Continuously charging the batteries will not damage the Instrument or the battery pack.
        Also, it is recommended to leave the charging unit a least one-day prior to using the Instrument.
        It is no recommended to use the GFAL-A when the BATT LOW alarm LED is light up, to continue operating the instrument.
          Install the charging unit and when the BATT LOW alarm LED turns off the GFAL-A is ready to be use again.
        If the battery assembly is completely discharged the Instrument has to be charge for a least 2 hr. before can be use.
        The GFAL-A can be used with the charger connected to the main AC line. 
        The GFAL-A should provide 24 hr of continuous operation when the battery pack is full charge.

          Battery pack replacement
          Remove only the 10 screws around the edge of the front panel.
        The battery pack is attached to the PCC, remove the tie-wrap and installs a new pack
        It is recommended to leave the charging unit a least one-day prior to using the Instrument.
          If after 2 hr. of charging the Instrument the BATT LOW alarm turns off the GFAL-A can be use with the charging AC adapter
        unit connected to the AC power.


        Battery Specifications

        Four AA, NiMH, 1.2 VDC batteries, the voltage at full charge about: 5.6 VDC
        Current Capacity:   2300 mA
        CAUTION:  
        Replace the battery pack only with NiMH batteries with the same nominal voltage and current capacity to avoid damaging the Instrument.

       
          8.0 – GFAL- A, Appendix B, Special application
        To find the value of fault resistances from each polarity with respect to site ground on a DC distribution system. 
           Let calculate these fault resistance in a 130 VDC distribution system with a predominant negative ground fault.
           Note: All the voltage readings are in absolute value no signs attach to the readings.

        1) Measuring the voltage of the Positive polarity with respect to site ground:

                                        V1 = 90.0 V

           2) Measuring the voltage of the Negative polarity with respect to site ground: Used for
                                          V2 = 40.0 V

           From the positive polarity of the GFAL-A select a resistor Rfix with respect to ground that will change the distribution system
         positive voltage with respect to ground for no more of 5% to 10% of it original value, assume that this resistor is:

                                          Rfix = 40 K Ohm
 

        There will be some voltages changes with respect to site ground now.
          Voltage from the Positive polarity with respect to ground after the Rfix resistor has been installed
                                        V11 = 81.0 V
                             
        Voltage from the Negative polarity with respect to ground after the Rfix resistor has been installed
                                        V22 = 49.0 V

        To calculate the fault resistance from the negative polarity (Rneg)
    
        Rneg = Rfix (V22 / V11 - V2 / V1)
           
          Rneg = 40 K (49.0 / 81.0 - 40.0 / 90.0)
    
        Rneg = 40 K (0.605 - 0.444) = 6.44 Kohm

        To calculate the fault resistance from the positive polarity (Rpos)
    
        Rpos = Rneg ( V1/ V2 ) = 6.44 K ( 90.0 / 40.0) = 14.49 Kohm
           
          If there is a predominant positive ground fault just apply the same procedure, however install the fix resistor
        Rfix in the negative polarity to do the calculations.


        Note: If some resistance of knowing value still attached to the DC distribution system with respect to site ground, like the
        voltage divider by an extra step in the calculation the value of the fault resistances with respect to ground from each
        polarity can accurately be calculated.

        Consult Samco Engineering to obtain these extra steps.

            --------------------------------------------------------------------------------------------------------------------------------------------------
        9.0 – GFAL- B
                                GFAL- B, DC Ground fault Tracker unit

    GFAL-B locator unit
                                                        Fig 2

       
10.0 – GFAL- B
        Introduction
        The GFAL-A/B method to indicate and locate DC ground faults is made up of two parts instruments.

          Instrument A
        GFAL-A is the interrupter unit, this unit also can be use as a separate DC ground fault analyzer instrument.

        Instrument B
        The GFAL-B is the “tracker” instrument, this unit require the GFAL-A to operate.

        10.1) Description     Input connectors on the GFAL-B

        CHARGER
        Input connector for the 12-18 VDC battery charger unit, the center point is the positive polrity
        The green LED will be on when the charger unit is connected to the GFAL-B.

        SENSOR
        Input connector for the sensor test probe.
        Note: The connector is a keyed and Snap-On type of operation
       
        10.2)  
 

        POWER switch
        In the ON position turn the unit on, in the OFF position turn the unit off.
        With the POWER switch at the OFF position it is OK to re-charge the battery assembly.

        10.3)    
        Alphanumeric display, MILLIAMPS

        For software, battery low and milliamps information.
        The default or maximum mA current that can be display is plus (+) or minus (–) 50.0 mA.

        PULSE TRACKER LED
        Will be briefly on (every 12 seconds a part) at the beginner of each tracking pulse cycle and will be off for the
        rest of the cycle.


        CHARGER LED

        The charger LED will be illuminate when the power adapter is connected to the power main.

        11)    GFAL- B, Applications

          The main application of the GFAL-B instrument is to track with the attached sensor unit the signal produce by
        the GFAL-A throughout the DC distribution system to locate the ground fault.
        Also is use to find magnetic interferences
        If there are one or several ground faults in the range of the instrument specification, it will locate these faults.
       
        AImportant Note:

        The GFAL-B will stop working after 12 hrs of continuos operation, need to be turn off and on again and re-synchronize

        12)    GFAL- B, Specifications
          Operating DC range                  12 to 270 VDC
        Impedance Range                     No load to the DC system
        Environmental                         30 to 125 Degrees F
        Power source input                  12-18 VDC
        Internal battery operation          24 hr (Rechargeable)
        Display                                    LCD Alphanumeric       
        Dimensions                              12” x 7.5” x 11” 
        Weight                                    4 Lb.
        Case in 2 colors                       Gray and yellow
        Warranty                                1 yr. Parts and Labor

        13) GFAL- B, Appendix C, Battery Pack Maintenance

        The internal battery assembly consists of four (4) AA Nickel Metal Hydride (NiMH) cells. Current capacity 2,300 ma
        The final voltage of the pack at full charge is approximate 5.6 VDC.

         Charging the Pack

        If the letter “b” (low battery alarm indication) appears in the alphanumeric display, is time to recharge the battery pack.

        A battery charging adapter unit is furnish with the GFAL-B, the adapter has a nominal output voltage of 12 to 18 VDC
        and a current capacity no less of 500 mA


        Continuously charging the batteries will not damage the Instrument or the battery pack.

        The GFAL-B can be used with the charger connected to the main AC line
        Is recommended to leave the charging unit connect to the GFAL-B a least one-day in advance to use the Instrument.
        It is not recommended to use the GFAL-B when the letter “b” is displayed.
        To continue operating the Instrument, install the charging unit and when the “b” alarm disappear, the GFAL-B is ready    
        to be use again.


        If the battery assembly is completely discharged, will be no alphanumeric display, the Instrument has to be charge for
        a least 2 hr. before can be use.

        When the battery pack is full charge, the GFAL-B should provide 24 hr of continuous operation.
       
        Battery pack replacement

          Remove only the 4 screws around the edge of the front panel.
        The battery pack is attached to the PCC, remove the tie-wrap and install a new pack
        It is recommended to leave the charging unit a least one-day prior to using the Instrument.

        Battery Specification
        4 NiMH, 1.2 VDC AA batteries, the voltage at full charge about: 5.6 VDC

        Current Capacity:   2300 mA
        CAUTION
        Replace the battery pack only with NiMH with the same nominal voltage and current capacity to avoid
        damaging the Instrument.


        14.0 – Appendix D, GFAL-A/B Method “Locating DC ground Faults”
       
NOTE:
                    It is very important to read all the "Application Notes" about the GFAL-A/B to master the art
                    of DC ground fault location


        14.1)    Introduction
        The GFAL-A (Fig.1) unit provides the means to analyze the DC distribution system  by introducing
        a fix resistor to site ground and complete an electrical circuit through the site ground fault resistance and the
        battery system (Fig.3).

        Also, makeup synchronization with the detector unit GFAL-B (Fig.2) via the LOC FLASH PULSE switch, and front
        panel FLASH PULSE LED visualization.


        GFAL a b setup
        14.2)    Troubleshooting a DC Distribution System (DS)
        To begin troubleshooting a DC DS Install the GFAL-A in a location close to the Battery Room or main DC circuit breaker panel
         be very carefull wh
en making connections or working on DC DS energized line or equipment. 
        The operation of the GFAL-A Interrupter will disrupt the Control Room DC ground fault display and or DC alarm system. 
        Always communicate with the control room operator before install and turn on the GFAL-A interrupter.


        Before attach the interrupter to the DC DS disconnect as possible any instrumentation or electrical apparatus that has a
        connection or resistance between the DC 
distribution system and site ground  e.g. voltmeter, DC alarm light bulbs or relays.
        This operation will eliminate unwanted activation of such equipment and will increase the sensitivity and range of the
        troubleshooting procedure.


        A) Set the GFAL-A FUNCTION SELECT switch to the OFF position.
        Connect the PROBE GREEN ground cable to site ground.
        Connect the PROBE RED positive cable to the battery positive polarity.
        Connect the PROBE BLACK negative cable to the battery negative polarity.

        B) Turn the GFAL-A FUNCTION SELECT switch to the AC/CONT position.
        Verify that the AC voltage with respect to the site ground is within the limits established by the site DC DS specifications.
        Normally this reading should be no more than 5.0 VAC in DC DS, however UPS installations without input transformer
        could have a substantial VAC reading.


          C)  Turn the GFAL-A FUNCTION SELECT switch to the POS/NEG position.
        Verify that the positive polarity voltage with respect to the negative polarity voltage (battery voltage) is within the limits
        
established by the site DC DS specifications.
   
        D) Turn the GFAL-A FUNCTION SELECT switch to the POS/GND position.

        Verify that the positive polarity voltage with respect to site ground is within the limits established by the site DC DS specifications.
        Normally this reading is half of the battery voltage plus or minus 10%.

        If the voltage reading of the positive polarity is bigger for more than 20% of the voltage reading of the negative polarity,
        then the distri-bution system has a predominantly negative fault.

        Remark    
        Using the voltage imbalance as an indication of DC ground fault activity is valid only if the method to calculate the ground fault
        from each polarity is applied first and the value of the fault resistance from each polarity is calculated.

   
        Look at:  Application 8.0 – GFAL-A Appendix B
        To find the value of the fault resistance from each polarity with respect to site ground on a DC distribution system.

        E) Turn the GFAL-A FUNCTION SELECT switch to the NEG/GND position.

        Verify that the negative polarity voltage with respect to site ground is within the limits established by the site
        DC DS specifications.

         Normally this reading is half of the battery voltage plus or minus 10%.

        If the voltage reading of the positive polarity is smaller for more than 20% of the voltage reading of the negative polarity,
        then the distri-bution system has a predominantly positive fault.


        F) How to locate a predominant positive fault
        For a predominant positive fault set the FUNCTION SELECT switch to the NEG/GND position.

        Set the NEG POLARITY TO GND switch to the 80 K-OHM position.
        If the MILLIAMPS display is less than 03.0 mA rotate the NEG POLARITY TO GND switch to 60 K-OHM position
        or less untill the reading is more than 03.0 mA.

        It is recommended no to increase the tracing current for more than 10.0 mA.

        14.3)    GFAL- B, Set up
        The Ground Fault Analyzer and Locator GFAL-B (Fig. 2) is a hand held microprocessor based unit, that provide
        a display signal with a blue LED to help synchronize the GFAL-A, takes the signals from the attach PROBE sensor
        and display fault current measurements in mA.


        A)    Synchronization procedure
        A synchronize visual signal is needed to synchronize the GFAL-A with the GFAL- B.
          The GFAL-A and the GFAL-B repeats a cycle every 12 seconds, where 6 seconds are used for test and 6 seconds are
         used for reference.

          Because there is not hardware connection or a transmitted signal between the two units the synchronization process
         is accomplish by direct operator intervention.  

   
        Turn the POWER switch of the GFAL-B to the ON position.
        When the PULSE TRACKER LED on the GFAL-B turn momentarily on is an indication that the test cycle has begun
        and the reference part of the cycle has ended.  


        After the PULSE TRACKER LED at the GFAL-B turn on and them off wait for approximate 5 seconds, them rotate
        the FUNCTION SELECT switch at the GFAL-A to the LOC p
23.22.44.45osition.

        On the next several cycles of the two units there will be a shift between the FLASH PULSE LED at the GFAL-A and
        the PULSE TRACKER LED at the GFAL-B.


        By activating the GFAL-A PULSE TRACKER switch to the FAST or SLOW position, the cycle on the GFAL-A and
        GFAL-B should be available to synchronize.


        Hint
        If the FLASH PULSE LED at the GFAL-A turn on before the PULSE TRACKER LED at the GFAL-B turn on, move
        the PULSE TRACKER switch to the SLOW position.

        If the FLASH PULSE LED at the GFAL-A turn on after the PULSE TRACKER LED at the GFAL-B turn on, move
        the PULSE TRACKER switch to the FAST position.

        When the two flashing LED’s turn on and off about the same time the two unit are synchronize

          
          15.0)   Locating DC ground faults
        15.1) Install the GFAL-A as explained in Appendix D
          15.2) Synchronize the 2 units as explained in Appendix D 
        15.3) Connect the magnetic sensor attach to the GFAL-B around the positive and negative cable of a branch of a DC
                distribution system where a search for a ground fault is suspected to exist.

                The main DC breaker panel is the best choice for this initiation task.
                Wait for at least four complete cycles and observe the GFAL-B MILLIAMPS reading.
                If no fault exists in the first branch tested, select another branch until the ground fault has been located.
                If the MILLIAMPS reading on the GFAL-B is continuously more than + or - 3 mA a branch with a ground fault
                has been identify.


        NOTE:
                It is very possible that more the one branch will have ground fault, in this case adding all the reading from the
                GFAL-B should be near or equal to the reading of the GFAL-A.


        15.4)   At the end of the test
        Disconnect the GFAL-A and reinstall any equipment or apparatus removed before ground fault troubleshooting.      
        Inform the Control Room or supervisor authority immediately after finishing troubleshooting.

        16.0 – GFAL- A/B, Warranty and Contact Information
        Samco Engineering warrants this product the GFAL-A/B to be free from defects in material and workmanship
        for a period of 1 year from the date of shipment.


         LIMITATION OF WARRANTY
        This warranty does not apply to defects resulting from unauthorized modification or misuse of the Instrument. 
          This warranty does not apply to the replacement of the battery unit.
          This warranty is instead of all other warranties, expressed or implied.
        Repairs will be made and the instrument returned with transportation prepaid.

          REMARK
        Samco Engineering shall not be liable for any indirect, special or consequential damages resulting from the use    
        of this instrument.


        Contact Information:
        Samco Engineering

          Fountain Valley, CA 92708
        Phone: (714) 235 - 5901
        E-mail: samcoeng@aol.com
        Web-site: http://www.samcoeng.com
                                                                   2017                                           Return to Home page