What Is an Electrostatic Voltmeter?

Electrostatic voltmeter refers to a meter or device that measures the steady-state voltage using the principle of electrostatic force. Direct measurement of DC high voltage and AC high voltage up to 1MHz.

Common voltmeter

The advantage of electrostatic voltmeter is that it can directly measure high voltage, the highest range can reach 500 ~ 1000 kV, the input impedance is extremely large and it basically does not draw power from the circuit.

Its disadvantages are large volume, inconvenient carrying, measurement accuracy and reliability are easily affected by mechanical vibration and wind, and it is generally not suitable for outdoor use. Nowadays, there are insulated and sealed electrostatic voltmeters, which are small in size and less affected by the environment during use, but the overall structure is more complicated. ^[2]

There are two types of electrostatic voltmeters, one is an absolute voltmeter, and the other is an engineering voltmeter, which is a non-absolute meter.

The so-called absolute meter electrostatic voltmeter means that when

The electrostatic voltmeter can be used to measure DC voltage and AC voltage, and it can also measure voltage up to 1MHz.

The advantage of an electrostatic voltmeter is that it basically does not absorb power from the circuit, or it absorbs only a very small amount of power. When measuring DC voltage, the meter does not absorb power from the circuit except for a moment when the circuit is turned on (the electrode of the meter is charged). When measuring AC voltage, the amount of current passed by the meter depends on the frequency of the measured voltage Because the capacitance of the meter is generally only a few picofarads to tens of picofarads, the power absorbed is also very small, so the internal impedance of the electrostatic voltmeter is extremely large. ^[3]

(1) Before use, place the electrostatic voltmeter stably, adjust it to a horizontal position, adjust the reflected light to the zero position of the scale, and stand firmly on a flat floor to prevent it from falling over.

(2) Check whether the power supply voltage meets the switching position of the light source voltage, so as not to burn out the light source bulb.

(3) The scale of the electrostatic voltmeter is not uniform. The range of the meter should be accurately selected so that the measured voltage value is about half of the scale. It is strictly prohibited to use it under overpressure to avoid damage to the instrument and pay attention to the cleanness and dryness of the surface.

(4) Attention should be paid to prevent errors caused by on-site stray electric fields, micro vibration, and wind.

(5) Ground the base of the electrostatic voltmeter well.

(6) Connect the tested high-voltage lead to the pressure equalizing ball on the top of the electrostatic voltmeter firmly, and protect a sufficient safety distance from the ground wire.

(7) After checking the wiring of all parts, you can measure. If measuring AC voltage, place the meter stop on the AC voltage block. If measuring DC voltage, place the meter on the DC voltage block.

(8) Load high voltage, strictly pay attention to the safety distance of operation, ensure the safety of operation, and record the data.

(9) After the measurement is completed, reduce the voltage until the meter displays 0, and then remove the test circuit after discharging.

(10) The capacitance of the electrostatic voltmeter is very small, it is 5 50pF. It can measure the large-capacitance test object and use it at low-frequency voltage, and the accuracy is higher; There is a certain error when measuring under the condition of voltage. ^[4]