Nortech F20 User Manual Download

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F20

Twin Earth Fault Indicator

Page 8 of 16

3.3

Indication with DC reset signal

time

fault current

time

LED indication

and relay contacts

time

DC reset signal

Fault 1

Fault 2

Fault 3

In all cases RTU sends DC

reset signal as soon as F20

indication is detected. F20

resets within 1 second of

DC reset signal

Indications with DC reset connected

Summary of Contents for F20

Page 1: ... Nortech Management Ltd United Kingdom November 2016 www nortechonline co uk Doc ref D_001116 F20 Twin Earth Fault Indicator USER MANUAL Version 1 2 ...

Page 2: ...ess for a particular purpose NML may make changes or improvements in the software equipment or specifications described in this document at any time and without notice These changes may be incorporated in new releases of this document This publication could contain technical inaccuracies or typographical errors NML shall not be liable for any damages including but not limited to consequential indi...

Page 3: ...Indication with no electrical reset 7 3 2 Indication with AC reset signal 7 3 3 Indication with DC reset signal 8 4 Installation 9 4 1 Physical 9 4 2 CT earthing 9 4 3 CT connections 10 4 4 Wiring connections 11 4 5 Enclosure Mounting 12 4 5 1 Enclosure options 12 5 Maintenance 13 5 1 Technical Assistance 13 5 2 Simple Test 13 5 3 Primary Injection 13 5 4 Replace battery 13 5 5 Recycling 13 6 Spec...

Page 4: ...the passage of fault current is given by a flashing LED for a pre set time period At the same time the relay contacts operate giving an electrical remote alarm On completion of the time period the unit will automatically self reset and is then ready to detect subsequent faults The F20 may also be manually reset remotely reset via a telecontrol DC reset signal or on restoration of AC supplies Each ...

Page 5: ...F20 may be reset early at any time during the indication period by pressing the RESET button on the front of the F20 Once the button is released the F20 will be reset to the ready state Each Earth fault element has its own reset button Electrical The F20 may be reset early at any time during the indication period by either a DC pulse from a telecontrol RTU or on restoration of a local AC supply El...

Page 6: ...f the F20 is achieved by pressing each of the TEST buttons When pressed the associated LED will flash however the output contacts will not operate This simple test proves the processor LED test button and battery are healthy It does not test the integrity of the CT connections or output contacts A primary injection into the CT arrangement is the best local test available Nortech supply a portable ...

Page 7: ... while Fault 3 is on the network 3 1 Indication with no electrical reset time fault current time LED indication and relay contacts 3 hours 3 hours Fault 1 Fault 2 Fault 3 Unit starts indication for fault 1 Fault 2 not detected as already indicating Reset at end of 3 hour timer Indications with timer reset only 3 2 Indication with AC reset signal time fault current time LED indication and relay con...

Page 8: ...ication with DC reset signal time fault current time LED indication and relay contacts time DC reset signal Fault 1 Fault 2 Fault 3 In all cases RTU sends DC reset signal as soon as F20 indication is detected F20 resets within 1 second of DC reset signal Indications with DC reset connected ...

Page 9: ... position over the cable sheath or screening tape and in accordance with local safety regulations When an earth fault occurs in a cable network the majority of return current will flow through the cable sheath thus resulting in a null output from the core balance CT as shown in the figure below INCORRECT Earthing Incorrect Earthing This effect can be prevented if the cable earthing connection betw...

Page 10: ...is a factory set option Wire the summated output from the CT secondary s to the CT terminals of the F20 The current transformers should be connected as shown in the diagram it is important that the polarities are as shown Wire the output from the CT secondary to the CT terminals of the F20 3 phase CT connections Single core balanced CT connection ...

Page 11: ...correct polarity DC Reset Apply 12V 24V dc between terminals 15 16 for 1s to reset both of the EF elements Observe correct polarity EF element 1 CT connections Observe the CT ratio expected in the example above 500 1 Connect CT secondary positive outputs to terminals 1 2 3 Terminals 1 2 3 are internally connected together on the F20 pcb Connect CT secondary common output to terminal 4 EF element 1...

Page 12: ... 122 0mm 90 0mm 4 off Mounting holes 110 0mm Rear view of F20 enclosure F20 enclosure fixing holes 4 5 1 Enclosure options The F20 can be supplied with custom drillings cable entry glands and blanking The F20 can be supplied with different depth enclosures if required An optional switchgear leg mounting bracket is available Please contact Nortech with your requirements or ask for a full list of av...

Page 13: ...rent into the CT s is recommended For core balanced CTs mounted external to the switchgear Nortech manufacture a Test Set which can be used for this purpose For phase CTs mounted internal to the switchgear it is often considered unnecessary to retest the CT wiring to the F20 5 4 Replace battery The battery will provide up to 20 years life and 1000 hours of flashing indication or 500 hours if both ...

Page 14: ...e Reset 12V 24V dc for 1000ms AC Remote Reset 90V 240V ac for 10 seconds 6 2 EMC The F20 indicator has been designed for compliance in accordance with the high level standard 61326 1 2006 industrial class Immunity ESD IEC61000 4 2 4kV contact 8kV air EM Field IEC61000 4 3 10V m 80MHz 1GHz 3V m 1GHz 2GHz 3V m 2 0GHz 2 7GHz Power Freq Mag Field IEC61000 4 8 Not Applicable Power and I O Signal Lines ...

Page 15: ...dity 0 95 non condensing Storage In addition to the above environmental considerations the F20 should be stored in an environment that is dry corrosive free and not in direct sunlight Correct storage Prevents premature component failures caused by environmental factors such as moisture or corrosive gases Exposure to high humidity or corrosive environments will prematurely degrade the electronic co...

Page 16: ...ircuit crush dissemble or heat above 100 C incinerate or expose contents to water LEDs Warning the EFI element LEDs are very bright Do not look directly at the LEDs AC Reset only where connected by user Isolate from mains before removing cover 100 240V AC 50 60Hz 100mA rated current Disposal Battery and F20 unit should be disposed of in accordance with local regulations ...

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