Introduction of Kunshan voltmeter manufacturers classification of voltmeters

Mechanical indicating ammeter for measuring DC voltage and AC voltage. It is divided into DC voltmeter and AC voltmeter.

DC type

It mainly adopts the measuring mechanism of magnetoelectric ammeter and electrostatic ammeter. The magnetoelectric voltmeter consists of a small range magnetoelectric ammeter and a series resistor (also known as a voltage divider). The low range is more than ten millivolts. In order to expand the range of voltmeter, the resistance value of voltage divider can be increased. For example, when using a 50 microampere ammeter to form a 250 volt voltmeter, the total resistance of the voltage divider and the measuring mechanism should be 250 / [50] × 10^(-6)]=5 × 10 ^ 6 ohm = 5 megohm, which is equivalent to the internal resistance of the voltmeter of 20 Ka ohm / v. In order to avoid too much access to the voltmeter affect the original working state, the voltmeter is required to have high internal resistance. A multi range voltmeter can be formed by series connection of a voltage divider composed of several resistors and a measuring mechanism. The low range of electrostatic voltmeter is tens of volts, and the expansion of the range is achieved by changing the internal structure and the distance between electrodes. In addition, the measuring mechanism of electromagnetic meter can also be used to measure DC voltage in theory.

Types of communication

It mainly adopts the measuring mechanism of rectifying ammeter, electromagnetic ammeter, electric ammeter and electrostatic ammeter. In addition to the static voltage meter, other voltage meters are made of small range ammeter and voltage divider in series. A multi range voltmeter can also be formed by series connection of a voltage divider composed of several resistors and a measuring mechanism. It is difficult to make AC voltmeters of these series into low range ones. The low range ranges from a few volts to several tens of volts, while the high range ranges from 1 kV to 2 kV. The low range of electrostatic voltmeter is about 30 V, while the high range is very high. The high voltage voltmeter used in power system is composed of electromagnetic voltmeter with rated voltage range of 100 V and voltage transformer with appropriate voltage transformation ratio. Due to the limitation of the coil inductance of the measuring mechanism, the frequency range of the electromagnetic system voltmeter and the electric system voltmeter is narrow, and the upper limit frequency is less than 1 ~ 2 kHz. The electric system is slightly better than the electromagnetic system. The use frequency range of electrometer and thermoelectric voltmeter is wide. The upper limit frequency of the rectifier voltmeter is about several kilohertz, but it should be noted that the reading of the rectifier voltmeter is correct only when the AC voltage is sinusoidal. The range, frequency range, internal resistance and accuracy level of each voltmeter are shown in the table.