Method and device for measuring no-load back electromotive force of pumping unit and permanent magnet motor of pumping unit

Abstract

The invention provides a pumping unit and a method and a device for measuring no-load counter electromotive force of a permanent magnet motor of the pumping unit.According to the method for measuring the counter electromotive force, active power of a to-be-tested permanent magnet motor is calculated in real time, the travel process of the pumping unit is determined, when the pumping unit is determined to be in the travel process, the currently calculated active power PK is compared with the preset power threshold value, when the active power PK is determined to be equal to the preset power threshold value, power supply to the to-be-tested permanent magnet motor is stopped, then the currently collected rotation speed n of the to-be-tested permanent magnet motor is compared with the rated speed N of the to-be-tested permanent magnet motor, and when n is equal to N, the currently collected voltage of the open circuit on the stator winding side is the counter electromotive force of the permanent magnet motor of the measured pumping unit.The device and the method can conveniently measure the no-load counter electromotive force of the permanent magnet motor on a whole pumping unit on a pumping unit working site.

Description

technical field [0001] The invention relates to the field of an oil pumping unit and a permanent magnet motor of an oil field pumping unit, in particular to a method and a device for measuring no-load counter electromotive force of an oil pumping unit and a permanent magnet motor of the oil pumping unit. Background technique [0002] The permanent magnet motor has three characteristics, and the motor has high efficiency: the rotor uses NdFeB permanent magnet material to replace the traditional electric excitation, which reduces the excitation loss. Small no-load loss Po < 4%Pe, asynchronous motor no-load loss Po > 12%Pe, efficiency can reach 94%, which is more than 12% higher than that of asynchronous motor; large starting torque: starting torque multiple is 3.8 times, ordinary motor 1.6 to 1.8; high operating power factor: high power factor can be obtained when operating at rated voltage, power factor > 0.9, reactive power saving effect is quite significant, so per...

AI Technical Summary

Problems solved by technology

However, both of these two measurement methods need to transport the permanent magnet motor of the pumping unit back to the test site for testing, which requires a lot of manpower and material resources, and is extremely inconvenient to use

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