WatchfulEye WTH-CS-1000V Manual

Portable Surge Protective Device Tester
Of all similar SPD testers, it is probably the lightest,
smallest tester with the most accurate test data
and the most durable battery
Working Principle of a Surge Protective Device
The core component of a surge protector is a nonlinear component inside. According to the different nonlinear
components, surge protectors can be classified as switch-type (the core component is mainly GDT) and voltage-limiting
type (the core component is mainly MOV).
Although the working principles of GDT and MOV are different, the basic characteristics are very similar: when there is no
over voltage, their impedance is very high, generally megohm level, which is almost equivalent to an open circuit. When
an over voltage occurs, the impedance quickly drops to a few ohms, and the surge current will flow into the ground
through the surge protector instead of entering the equipment. At the same time, as the impedance of the surge protector
at this time is small, the voltage on both sides is also relatively small, and it is connected in parallel with the protected
equipment, it also prevents the equipment from withstanding large surge voltages. In this way, it has the effect of draining
and limiting the pressure.
Importance of Leakage Current Parameters
With the extension of the service life of the voltage-limiting surge protector, the gradual aging of the MOV chip will be
accompanied by an increase in leakage current. The increase in leakage current will cause overheating, accelerated
aging, and failure of the surge protector.
If we do not pay attention to the aging curve of the surge protector and replace it in time, once the surge protector cannot
disconnect in time when getting overheating due to increasing in leakage current, it will more likely cause an explosion,
and more seriously, it may cause a fire.
Importance of Break-over Voltage Parameters
The break-over voltage of surge protector is the voltage value measured when the current flowing through the surge
protector is 1 mA when the test voltage increases.
Has the surge protector in the system been broken down?
Can the SPD which has been used for years continue to be used?
If the L-PE voltage of the power grid system is 277V, is the selected surge protector correct?
Normally only the value of UC is marked on the surge protector. What is the actual break-over voltage in response to the
surge current?
All of problems above will be solved when break-over voltage parameters are measured.
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