Use a multimeter or a megohmmeter to check the wiring?
Check the AC and DC voltage of the line; it is convenient to use a pointer type multimeter or set a multimeter for the connection and disconnection of the line. The picture below shows the UT61C digital multimeter.
If you check the AC current in the line, it is more convenient to purchase a digital clamp meter.
The motor and cable conductors that need to measure the insulation resistance of the circuit should be checked with a megohmmeter;
They determine the scope of use according to their functions, and the megohmmeter is the best choice for detecting the insulation of electrical equipment; it cannot be replaced by a multimeter; because the resistance value of the insulation resistance of the electrical equipment to be tested is relatively large, all in the range of several megohms Or more than tens of megohms, the scale of the multimeter is very inaccurate in this range. In addition, the power supply voltage used by the multimeter to measure the resistance is very low (below 9V), and the resistance value presented under the low voltage cannot reflect the true value of the insulation resistance under the action of the high voltage. Therefore, although the multimeter can also measure the insulation resistance value of thousands of ohms, the insulation resistance value measured by it can only be used as a reference. When testing the insulation resistance of electrical equipment, only a high-voltage and low-current megohmmeter (250~2500V) can be used for measurement, and a multimeter cannot be used.
The multimeter is a multi-function, multi-range portable instrument. According to different measurement principles and display methods, it can be divided into pointer multimeter and digital multimeter.
Multimeters can generally be used to measure DC current, DC voltage, AC voltage, resistance, level, etc., and some can also measure AC current, capacitance, inductance, and the magnification of transistors, etc., so it is indispensable for electronic engineering, electromechanical and maintenance departments. It is widely used in electrical measurement.
The pointer type multimeter, also known as the analog type multimeter, is a multi-purpose measuring instrument with the meter head as the core component. The measured value is read by the pointer of the meter head. It can continuously observe the dynamic changes of the measured value. The MF47 pointer type multimeter As shown below.
The digital multimeter is an instrument that integrates electronic technology and microcomputer technology. It uses a liquid crystal display to directly display the measured value, which fundamentally changes the circuit and structure of the traditional pointer multimeter. It has the advantages of small size, light weight, wide measurement range, It has the advantages of multiple measurement functions, intuitive reading, fast measurement speed, high measurement accuracy, high sensitivity, and strong overload capacity.
