I. How to measure the quality of submersible pumps
There are single-phase submersible pumps and three-phase submersible pumps, and the measurement methods of the two submersible pumps are somewhat different.
1. Single-phase submersible pump
Use the 2K digital multimeter to measure the DC resistance of the running winding and the starting winding, respectively. Adding up, it is approximately equal to the operation measured with a multimeter, and the resistance value of the series connection of the starting winding is normal.
In addition to checking the windings, the single-phase submersible pump also needs to check the capacity of the capacitor. To judge the capacity of the capacitor, set the gear of the digital multimeter to a gear slightly larger than the capacity of the capacitor, and then measure it directly.
2. Three-phase submersible pump
Use the 200Ω or 2K gear of the digital multimeter to judge the balance of the DC resistance of the three-phase windings. The DC resistance balance of the winding is close to or the same as normal. The error of the three-phase winding resistance value of high power is less than 1Ω, and it is better to be less than 3Ω for low power.
The only thing left is to check the insulation resistance. The inspection methods for single-phase and three-phase are the same. Use a shaker to shake the winding and the casing to insulate, and it is normal if it is greater than 0.5MΩ. To check the phase-to-phase insulation, it is necessary to disconnect the connection between the windings of each phase, and use a shaker to shake the insulation between the three-phase windings.
Second, how to use a multimeter to measure the quality of a submersible pump
Tools: an electronic clamp multimeter with an AC current measurement range.
Measurement method:
When measuring the water pump, first turn the multimeter to AC current above 20A. Open the “pliers”, cover any one of the live wire or the neutral wire, and turn on the power switch. Pay attention to see if there is current. If there is no current, there are generally two reasons: one is that the wire is broken, and the other is that the motor is broken. If there is current, and the current is relatively large, such as a submersible pump of one kilowatt, the working current should be about 5A. If the measured current is much larger than this value, there are two situations: one is that the rotor of the motor is blocked, cannot rotate, and is blocked. Turned, the current is very large. The second is that the insulation between turns of the stator winding of the motor is damaged, that is, the motor is burned.
The above is the method of measuring the current, and the method of measuring the resistance can also be used. Turn off the power switch, turn the multimeter to 200 ohm gear, and connect the two test leads to the live wire and the neutral wire respectively. If the water pump is normal, there should be a certain resistance value. If there is no resistance value at all, it can basically be judged that the motor coil is broken. .
Finally, pull the submersible pump out of the well, check the wire first, after confirming that there is no problem with the wire, turn on the power again to observe, if there is no movement, it can be determined that the motor is broken. If there is a heavy humming sound, it may be that the motor bearing is broken, or the water pump may be broken, please ask the master who repairs the submersible pump to repair it.
