PW-VP50 Polarity Checker
PW-VP50 CT Polarity checker is the favorable meter which can be used for field CT and transformer polarity test in power plants, substations and any other application which may need to check the polarity. There are 2 units included in PW-VP50. One master machine which can automatically inject high-precision pulse current with adjustable amplitude and period to the primary side of CT, three-phase at the same time. The other slave machine will receive and analysis the waveform of induced pulse current at the secondary side so as to judge the polarity is positive or negative automatically by the LED indicator on the kits.
This testing method is very simple, reliable and easy to use. There are built-in battery inside the kits and very small size so that engineer can use it to quickly complete the polarity detection work not only for CT, but also the the secondary protection relay circuit’s polarity check.
  • The master machine supports both single pulse trigger mode and cyclic pulse trigger mode. The sending period and current amplitude of pulse can be set freely, and three-phase output or single-phase output mode can be also selected.
  • The slave machine is connected to each secondary terminal of CT one by one, and the slave machine will automatically collect the waveform of induced pulse current for auto-judgment.
  • The test result, CT polarity, will be indicated through the indicator light and buzzer.
  • PW-VP50 adopts special design of constant current output mode so that it is with high load capacity.
  • Within built-in Li-Battery, The kits can work continuously for 8 hours with one full charging.
  • The test result of PW-VP50 will not be affected by the length of wiring, to ensure the stability and reliability of polarity test process.
  • The PW-VP50 adopts the hand-held structure design, small size, light weight,only 0.25 to0.5kg each unit.


Main Specifications




Master Machine


Phase Output Option       A phase/ B phase/ C phase / three-phase

Period Output Option      2s/3s/4s/5s

Current Output Option    1A/2A/3A/5A

Output Mode                   Single trigger/ Cyclic trigger

Power Supply                 Li-Battery

Battery Capacity            DC 7.4V(5000mAh)

Weight                            450g


Slave Machine

Polarity Check Mode           Automatic Check

Test Result Indication         LED light indicator and Buzzer

Power Supply                    4pcs AAA Alkaline 

Weight                               250g