How to use a multimeter to measure the pump motor good or bad
Our unit dormitory area has a water tower, played a deep well, and the use of deep water pump water. Leaders see that I like to mess with electrical appliances, the dormitory area pipe water water task to me part-time management, which I have time to spend on this, hands on the water tower designed to float up and down the movement to promote the lever top toggle the conversion switch, automatic power on the water, automatic shutdown.
As the AC contactor is inferior, which has a contact burned soluble and broken, which can cause the lack of phase, because the water went to check, found that the well like boiling, a check the problem, quickly power outage check, because the pumps of the enameled wire are used to insulate the plastic tube wearing in the water both heat dissipation and insulation, in order to confirm that whether it is burned? I measured it this way:
1, although the lack of phase, but did not cause tripping, indicating no leakage!
2, I know that submersible pumps are mostly star connection, each phase and ground resistance shall not be less than 0.5 megohm, the resistance between the phases should be as large.
3, but I only have a multimeter and stylus on hand, I will hit the multimeter to 10K file, measuring the resistance of each phase and ground, a measurement, very good, the head of the action is not at all, 10K file for zero. I use the ohm gear amount of resistance between the three phases, although the three phases were measured to forty or fifty ohms, the good thing is that the resistance between the three phases is equal, which is in line with the resistance value of the enameled coil.
Although the regulations set the leakage must be used to shake the meter, but in case of emergency, the multimeter 10K file to see the needle wobble can also determine the degree of insulation, because I tested the insulation of the transformer from the 10K file on the identification of the end of a certain amount of experience in measuring, where the 10K file on the pointer without the slightest movement, basically will not be a leakage.
I identified the pump no turn-to-turn short circuit and leakage, I re-bought a 380V AC contactor replacement, has been automatic water supply for a few years have not been out of order.
