How to measure the quality of 220v submersible pump with digital multimeter

How to measure the quality of 220v submersible pump with digital multimeter

How to judge whether the 220V submersible pump is good or not, we first use a digital multimeter to measure the power supply voltage, and then turn on the power to see if the submersible pump rotates, and there is still a buzzing sound. If it does not rotate, you check the following conditions, three wires One of them may be disconnected, open circuit, the pump motor winding is burnt out or the winding is short-circuited to ground, the capacitor is damaged, the bearing is worn, and there are foreign objects in the impeller and the shaft body is stuck.

1. First, set the digital meter to the maximum range, and use the red and black test pens to check the resistance values of the three wires and the casing of the pump motor. (The grounding must be good.) The closer the measured resistance value is to infinity, the better. Ten ohms is a short circuit to ground.

2. How to judge whether a capacitor is good or bad. Generally, digital multimeters have the function of measuring capacitors. When measuring, you can directly insert the two pins of the discharged capacitor into the Cx jack on the meter board, and select an appropriate range to read. Display capacity data. If the capacitor is good, the capacitance value of the capacitor will be close to the value picked up by the multimeter.

3. The method of measuring and judging the resistance value of the main and auxiliary windings. Generally, the resistance value of the running winding is a few ohms, and the resistance of the starting winding is more than ten ohms or tens of ohms. If the measured resistance is zero or a few ohms, it means that the winding turns are short-circuited, and if it is infinite, it means that the winding is open.

Fourth, the single-phase submersible pump has three terminals, use a digital multimeter
Measure the resistance value between the three wire ends, connect the capacitor in parallel between the two wire ends with the largest resistance, and connect the other wire end (common end) to one end of the power supply, and then use the electric barrier of the multimeter to measure the distance between the common end and the wire ends connected to the two ends of the capacitor. The resistor between them, the end with slightly larger resistance is the other end of the power supply.

Under normal circumstances, a multimeter can be used to basically judge whether the motor is burned. Before the measurement, the connecting piece of the three-phase motor should be removed, and then the three windings are short-circuited with the ohm range of the multimeter. The highest resistance range of the multimeter can be used.

If there is no resistance value in the measurement, it is basically confirmed that there is no short circuit between phases in the three-phase winding, and then measure each phase of the three-phase winding to the ground. If the resistance error of the three windings measured is very small, it can be determined that the motor is not faulty.

If one or two of the phases have an open circuit or a large resistance error, it can be determined that the motor is burned. If there is still doubt, you can remove the end cover for further confirmation.

Ohm Ω range, measuring the coil impedance, the resistance value is generally not large, 10k range is used to measure the leakage of the shell, the smaller the resistance value, the greater the leakage current, it is better to measure with a shaker, do not touch the metal part when measuring, it will affect the human body Measurement accuracy, the measurement of the inter-turn short circuit of the coil is somewhat difficult.