20Hz Injection Kit Monitoring System

20Hz Injection Kit Monitoring System

The Display used to monitor the 20Hz and 50Hz current passing through NGT transformer. This could help to monitor the stator earth fault and could record the current every minute. The current shall be displayed in milliamps for both 20Hz and 50Hz. If an earth fault occurs in the generator star point, the 20 Hz voltage drives a current through the fault resistance. The current can be measured using clamp-on CT which would be clamped between load resistor and NGT. It gives an indication of the current values are lower or higher than the set threshold.


  • 20Hz and 50Hz current can be monitored without affecting the working of the existing system
  • Records the current every minute
  • Indicates when current values are lower or higher than the set threshold
  • Low-Cost display with high accuracy
  • Different size of displays are available


Power Supply
Standard 85 to 260V AC, 1φ, (47Hz to 63Hz)

or 90V to 370V DC

Custom 36V to 72V DC (48V), 18V to 36V DC (24V)
Power Consumption <20W
Display Type 7 Segment Display
No of Digit 2 x 6 Digit
Format 20:XXXX (XXXX = 20Hz current in mA)

50:XXXX (XXXX = 50Hz current in mA)

Display Size 50mm/100mm/300mm
Color Bright Red
Input Signal
Current From clamp-on CT connected in NGT transformer path
Note: Ethernet-based input shall be provided for the display*
Operating Temp 0°to 50°C
Humidity 95% Non-Condensing
Enclosure Wall/Panel/Table Top Mountable
Protection Class IP20
Note: * Optional

Contact SANDS for the actual dimension of each model.


  • Stator earth fault protection system in large generators.