How to use a digital multimeter to measure the quality of a 220V submersible pump
How to judge the quality of a 220V submersible pump? First, we use a digital multimeter to measure the power voltage. Then, we turn on the power to see if the submersible pump rotates or there is a buzzing sound. If it does not rotate, you can check the following situations: one of the three wires of the electric pump may be disconnected or disconnected, the water pump motor winding may be burnt or the winding may be short circuited to ground, the capacitor may be damaged, the bearing may be worn, and there may be foreign objects in the impeller and the shaft may be stuck.
1、 Firstly, set the digital meter to its maximum range and use a red and black pen to check the resistance values between the three wires and the water pump motor casing. (The grounding must be good) The closer the measured resistance value is to infinity, the better. If the measured resistance is close to zero or tens of ohms, it is a short circuit to ground.
2、 How to determine the quality of a capacitor? Generally, a digital multimeter has the function of measuring capacitors. When measuring, the two pins of the discharged capacitor can be directly inserted into the Cx socket on the meter board. By selecting an appropriate range, the displayed capacity data can be read. If the capacitor is good, the capacity value of the capacitor will be close to the value found on the multimeter.
3、 The method for measuring and judging the resistance values of the main and secondary windings is generally a few ohms for the running winding, while the resistance of the starting winding is between ten or tens of ohms. If the measured resistance value is zero or a few ohms, it indicates a short circuit between turns in the winding, and infinity indicates a open circuit in the winding.
4、 Single-phase submersible pumps have three terminals, using a digital multimeter
Measure the resistance value between three wire terminals. The two wire terminals with the highest resistance are connected in parallel with a capacitor, and the other wire terminal (common end) is connected to one end of the power supply. Then use the resistance value of a multimeter to measure the resistance between the common end and the wire terminals at both ends of the capacitor. The slightly higher resistance value is at the other end of the power supply.
