Double-motor energy-saving device of oil pumping unit

Abstract

The invention relates to the field of oil field and oil well oil extraction equipment, and particularly discloses a pumping unit double-motor energy-saving device which comprises a starting motor, an operation motor, a motor control cabinet, a speed reducing mechanism and a pumping unit. The motor control cabinet controls the starting motor to start and drives the pumping unit to reciprocate up and down through the speed reducing mechanism; after the pumping unit runs for a set time, the motor control box controls the running motor to start, the starting motor stops, and the running motor drives the pumping unit to reciprocate up and down through the speed reducing mechanism. The starting state and the running state of the pumping unit are respectively provided with the motor, so that the requirements of the pumping unit on abnormal production states such as starting, wax blocking, sand blocking and scale blocking can be met, and long-term high-efficiency operation can be met. The original operation mode of the oil pumping unit is not affected when the operation motor is dismounted or damaged. The principle is simple, the energy-saving effect is obvious, novel equipment (such as a frequency converter and a permanent magnet motor) is not added, and daily operation, maintenance and management are the same as those of an original mode.

Description

Technical Field

[0001] The invention relates to the field of oil field and oil well production equipment, and in particular to a double-motor energy-saving device for an oil pumping unit. Background Art

[0002] The oil pump is the main mechanical equipment for oilfields. Since the oil pump has its own mechanical balance device and periodic pulsating load characteristics, the motor is required to have a high starting torque to ensure that the oil pump starts in a stationary state. In view of the particularity of the oil pump load, in order to ensure the smooth progress of oil production, the selection of the oil pump motor is generally based on the maximum torque as a reference value. At the same time, the oil pump cannot reduce the load torque to enable the motor to achieve light load start, which will extend the starting current time of the motor by 5-7 times, affecting the service life of the motor. In summary, the rated power of the motor can only be selected to be very large (generally 2-3 times). When the oil pump is started and the load decreases during normal operation, the motor works under light load. The average torque of the normal operation of the oil pump generally does not exceed one-third of the maximum torque. The load rate of most oil pumps is between 20% and 30%, and the maximum will not exceed 50%, forming a "big horse pulling a small cart" phenomenon, causing the power factor and efficiency of the motor to drop sharply. Test data show that the efficiency of the oil pump motor is mostly between 40% and 60%, and the power factor is between 0.2 and 0.5, causing serious losses.

[0003] The commonly used energy-saving methods for oil pump motors are: using the high-slip motor's large starting torque to reduce the equipped power of the oil pump motor; using the permanent magnet motor's large starting torque and high motor efficiency to reduce the equipped power of the oil pump motor and improve the operating efficiency of the oil pump motor; using the frequency converter to reduce the starting current of the oil pump motor and reduce the equipped power of the oil pump motor. However, the above technologies all have their own advantages and disadvantages: the high-slip motor has a large starting torque, but compared with the motors of the same specifications and power, the copper loss and iron loss increase; the permanent magnet motor is small in size, has a large starting torque, and has a high operating efficiency, but is expensive, and is easily demagnetized by heat, vibration, and long-term operation, forming a vicious cycle and causing permanent magnet motor damage; the frequency converter can reduce the starting current and the starting torque of the motor (the oil pump is a constant torque load), and can realize the convenient adjustment of the pump stroke, but after the AC-DC-AC voltage and current conversion, it is also an energy-consuming device, and when the filtering function is not strong, it is used in large quantities, and high-frequency harmonics will increase grid pollution. These energy-saving methods only reduce the power of the motor to a certain extent, and do not fundamentally solve the problem of the oil pump being "a big horse pulling a small cart". Moreover, some technologies increase the copper loss and iron loss of the motor and reduce the hardness of the mechanical properties, so the energy-saving effect is not ideal. Summary of the invention

[0004] Aiming at the deficiencies of various commonly used energy-saving technologies for oil pump motors, this invention provides an oil pump dual-motor energy-saving device, which uses two motors to be responsible for the oil pump startup state and the running state respectively, so as to improve the running load rate and running efficiency of the oil pump motor, since one oil pump motor needs to take into account both the startup state and the running state, which is difficult to achieve the best situation.

[0005] The technical route of this invention is:

[0006] First, analyze the start-up and operation status of the oil pump. The motor of the oil pump is started with load. Each time the oil pump is started, it starts from the dead point of the upper and lower strokes, that is, the maximum load torque. At the same time, the oil pump system has a large inertia and a long start-up time, which objectively requires the motor to have good starting performance. During the operation of the oil pump, affected by factors such as sand jam, wax jam, scale jam, viscosity, gas, vibration, leakage, etc., the load presents an impact periodic alternating load, which fluctuates greatly within a cycle, causing the irregularity and large volatility of the net torque curve of the crankshaft, especially sand jam, wax jam, and scale jam, which causes the load of the oil pump to increase sharply. The operation characteristics of the oil pump are large starting current and short running time; sand jam, wax jam, scale jam and other factors cause the load of the oil pump to increase sharply, and various treatment measures can be used to reduce the probability of this situation; the load fluctuation of the oil pump caused by factors such as viscosity, gas, vibration, leakage, etc. is relatively stable and has a long running time, which is the main state of the operation of the oil pump.

[0007] The second is to analyze the configuration principle of the pumping unit motor. Generally, the starting torque of a three-phase asynchronous motor is 1-1.2 times the rated torque, the maximum torque is 1.8-2.3 times the rated torque, and the starting current is 5-7 times the rated current. The motor generally adopts light load starting to reduce the starting current time and rated load operation, so that the motor operating efficiency and power factor are in a better state. However, the pumping unit is a constant torque load and cannot achieve light load starting. The general configuration principle of the motor rated power will prolong the motor starting time and the starting current operation time, which is easy to cause motor insulation damage and affect the service life of the motor. Therefore, it can only increase the motor power, on the one hand, increase the motor starting torque, on the other hand, it is equivalent to reducing the motor starting current (5-7 times the rated current of the rated power motor, equivalent to 2-3 times the high configuration power motor), thus causing the "big horse pulling a small cart" of the pumping unit motor configuration, which has become a common phenomenon in the configuration of the pumping unit motor, making the pumping unit motor operation efficiency very low.

[0008] The technical solution of this invention is:

[0009] Analyzing the operation of the pumping unit, three states can be obtained: one is the starting state, the second is the normal operating state, and the third is the abnormal production state where the load increases sharply due to factors such as sand jam, wax jam, and scale jam. The normal production state is the basis for the long-term and stable operation of the pumping unit. The existing pumping unit motor matching can only meet the instantaneous starting requirements at the expense of the long-term and efficient operation of the motor. The various conventional pumping unit energy-saving technologies are mainly to reduce the matching power of the pumping unit motor as much as possible to save energy. The energy-saving test effect is very good, but the ability to cope with changes in well conditions is weak. For this reason, dual motor processing can be used, that is, the starting motor is only responsible for the operation of the pumping unit starting and the state of sharp increase in load. Since it is a short-term operation, the motor power can be high-matched and the operating energy consumption is not high; the operating motor is responsible for the daily state operation, the motor power is optimally matched, and the efficiency of long-term operation is improved, so as to achieve the best energy-saving operation effect of the pumping unit without affecting the pumping unit startup and the abnormal production state response.

[0010] The dual-motor energy-saving device for the oil pumping unit invented in this invention includes a starting motor, a running motor, a motor control cabinet, a reduction mechanism and an oil pumping unit; the motor control cabinet controls the starting motor to start, and drives the oil pumping unit to reciprocate up and down through the reduction mechanism; after running for a set time, the motor control cabinet controls the running motor to start, the starting motor stops, and the running motor drives the oil pumping unit to reciprocate up and down through the reduction mechanism.

[0011] The starting motor and the running motor are installed on both sides of the reduction mechanism; the starting motor is equipped according to the starting power of the oil pumping unit specifications and models; the running motor is equipped according to the running power of the oil pumping unit specifications and models.

[0012] The motor control cabinet has the operation and protection functions related to starting, stopping, overloading, phase loss, stalling, short circuit, overvoltage, undervoltage, leakage, etc. of the starting motor and running motor.

[0013] The motor control cabinet is equipped with starting motor compensation capacitors and running motor compensation capacitors respectively.

[0014] There are three simplified ways to equip the starting motor and the running motor: the first is a dual-power motor that is designed and manufactured in an integrated manner for the starting motor and the running motor; the second is a dual-speed motor with changed pole pairs; the third is a Y-Δ motor; the high-power wiring is used as the starting motor, and the low-power wiring is used as the running motor.

[0015] The motor control cabinet controls the starting motor and the running motor, including the following steps: Step 1) Press the start button of the motor control cabinet to start the starter motor, driving the pumping unit to reciprocate up and down; Step 2) After the starting motor runs for a set time, the motor control cabinet starts the running motor; Step 3) The motor control cabinet stops the starting motor, and the running motor drives the pumping unit to do up and down reciprocating motion; Step 4) After the running current of the running motor exceeds the set value, the motor control cabinet stops the running motor and starts the starter motor to drive the pumping unit to do up and down reciprocating motion; Step 5) repeating steps 2), 3) and 4); Step 6) the motor control cabinet issues an alarm indicating that the well condition has changed; Step 7) When the running motor has phase loss, short circuit, overvoltage, undervoltage, leakage, or three-phase imbalance, the motor control cabinet stops the running motor and starts the starter motor to drive the pumping unit to reciprocate up and down; Step 8) the motor control cabinet issues an alarm indicating a motor failure; Step 9) When the starting motor is overloaded, lacks phase, is blocked, short-circuited, over-voltage, under-voltage, leaked, or three-phase unbalanced, the motor control cabinet stops starting the motor; Step 10) the motor control cabinet issues a starter motor fault prompt alarm; Step 11) Press the stop button on the motor control cabinet to stop the running starting motor or running motor.

[0016] There are three ways to implement the control steps of the motor control cabinet: the first is to use a variety of relay control circuits; the second is to use a PLC control system; and the third is to use a single-board computer system.

[0017] There are three implementation methods of the motor control cabinet control steps, all of which have remote transmission interfaces for starting the motor and running the motor's operating data and alarm status, and remote start and stop interfaces for the motor control cabinet.

[0018] Compared with the existing oil pumping unit motor energy-saving technology, the oil pumping unit dual motor energy-saving device of the present invention has the following advantages:

[0019] The pumping unit is equipped with electric motors for startup and operation respectively, which can not only meet the high torque requirements of the motor during startup and abnormal production conditions such as wax jam, sand jam, scale jam, etc., but also meet the long-term efficient operation.

[0020] The original pumping unit system only adds a small-power running motor and the corresponding control circuit. The technology is simple and easy to implement. For pumping units with frequent stroke adjustment, the small-power running motor can be equipped with a corresponding frequency converter to facilitate the stroke adjustment.

[0021] One motor is running while the other is rotating without electricity to prevent the motor shaft from being deformed due to gravity and long-term static state.

[0022] The running motor cannot be started alone, which reduces the chance of damage, and even if the running motor is damaged or removed, it will not affect the original operation mode of the pump.

[0023] Compared with high-slip motors and permanent magnet motors, running motors are equipped with low power and high operating efficiency; starting motors are equipped with high power and strong adaptability.

[0024] Compared with the inverter-controlled motor, the running motor is equipped with low power, which reduces the energy consumption link of the inverter and reduces the interference of high-frequency harmonics; the starting motor is equipped with high power and has strong adaptability.

[0025] It has a wide range of applications and is suitable for various types of oil pumping units, such as beam type and tower type. Starting motors and running motors can be selected according to on-site production needs and economic costs to optimize the starting and operation of the oil pumping unit.

[0026] This invention provides a dual-motor energy-saving device for oil pumping units, which has a simple principle, quick installation, convenient maintenance and management, low operating energy consumption, low failure rate, and obvious energy-saving effect. At the same time, no new equipment (such as frequency converters, permanent magnet motors, etc.) is added, and daily operation, maintenance, and management are compatible with the original operation and technical requirements. It will effectively solve the long-standing problem of "big horses pulling small carts" in various oil pumping units such as walking beam and tower types, so that various types of oil pumping unit motors can operate efficiently for a long time, and can also well meet the short-term operation with increased torque caused by changes in starting status and well conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Composition diagram of the dual-motor energy-saving device for oil pumping units.

[0028] Figure 2 Relay control circuit diagram of the dual-motor energy-saving device of the oil pump.

[0029] Figure numerals: 1-starting motor; 2-running motor; 3-motor control cabinet; 4-reduction mechanism. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Please refer to the attached drawings, an embodiment of the present invention is provided: a dual-motor energy-saving device for an oil pump, comprising a starting motor (1), a running motor (2), a motor control cabinet (3), a speed reduction mechanism (4) and an oil pump; the motor control cabinet (3) controls the starting motor (1) to start, and drives the oil pump to make up and down reciprocating motion through the speed reduction mechanism (4); after running for a set time, the motor control box (3) controls the running motor (2) to start, the starting motor (1) stops, and the running motor (2) drives the oil pump to make up and down reciprocating motion through the speed reduction mechanism (4).

[0034] The starting motor (1) and the running motor (2) are installed on both sides of the speed reduction mechanism (4); the starting motor (1) is configured according to the starting power of the oil pumping unit; and the running motor (2) is configured according to the running power of the oil pumping unit.

[0035] The motor control cabinet (3) has the operation and protection functions related to starting, stopping, overloading, phase loss, stalling, short circuit, overvoltage, undervoltage, leakage, etc. of the starting motor (1) and the running motor (2).

[0036] The motor control cabinet (3) is respectively equipped with a starting motor compensation capacitor and a running motor compensation capacitor.

[0037] The relay control circuit for realizing the starting motor (1) and the running motor (2) comprises a main circuit part of the starting motor (1), a main circuit part of the running motor (2) and a control circuit part.

[0038] The main circuit of the starter motor (1) consists of the isolating switch QS1, the fuse FR1, the AC contactor main contact KM1-1 and the motor integrated protector JD1. The power input isolating switch QS1, passes through the fuse FR1 and the AC contactor main contact KM1-1, passes through the motor integrated protector JD1, and is connected to the three-phase terminals of the starter motor M1.

[0039] The main circuit of the running motor (2) consists of the isolating switch QS2, the fuse FR2, the main contact of the AC contactor KM2-1 and the motor integrated protector JD2. The power input isolating switch QS2 passes through the fuse FR2 and the main contact of the AC contactor KM2-1, passes through the motor integrated protector JD2, and is connected to the three-phase terminals of the running motor M2.

[0040] The relay control circuit consists of isolating switches QS3, QS4, stop button SB1, start button SB2, starter motor protector coil JD1 and normally closed contact JD1-1, run motor protector coil JD2 and normally closed contact JD2-1 and normally open contact JD2-2, starter motor AC contactor coil KM1 and normally open contact KM1-2, time relay coil KT and normally open contact KT-1 and normally closed contact KT-2, run motor AC contactor coil KM2 and normally open contact KM2-2, count relay coil JS and normally closed contact JS-1. The control power input isolating switch QS3, one end is connected to the ground wire N, and the other end is connected to the stop button SB1, and then it is connected in parallel to three paths:

[0041] The first path forms a loop through the starter motor protector coil JD1 and the ground wire N.

[0042] The second path passes through the normally closed contact KT-2 of the time relay and the series start button SB2 (the normally open contact KM1-2 of the starting motor AC contactor and the normally open contact JD2-2 of the running motor protector are both connected in parallel with the start button SB2), and then is divided into two parallel branches. The first branch is composed of the normally closed contact KM2-3 of the running motor AC contactor, the normally closed contact JD1-1 of the starting motor protector, the starting motor AC contactor coil KM1 and the ground wire N to form a loop; the second branch is composed of the normally closed contact JS-1 of the counting relay, the time relay coil KT and the ground wire N to form a loop.

[0043] After passing through the isolating switch QS4, the third path is divided into three branches in parallel: the first branch is composed of the normally open contact KT-1 of the time relay (the normally open contact KM2-2 of the running motor AC contactor is connected in parallel with the normally open contact KT-1 of the time relay), the normally closed contact JD2-1 of the running motor protector, the coil KM2 of the running motor AC contactor and the ground wire N to form a loop; the second branch is composed of the coil JS of the counting relay and the ground wire N to form a loop; the third branch is composed of the coil JD2 of the running motor protector and the ground wire N to form a loop.

[0044] Operation steps of the motor control cabinet of the double motor energy-saving device for the oil pump:

[0045] Start: Close the isolating switches QS1, QS2, QS3, and QS4 respectively to energize the starter motor M1, the running motor M2, and the control circuit, the starter motor protector JD1, the running motor protector JD2, and the counting relay JS; press the start button SB2, the starter motor AC contactor coil KM1 is energized, the starter motor AC contactor main contact KM1-1 is closed, the starter motor M1 is energized to start running, the starter motor AC contactor normally open contact KM1-2 is closed, and the starter motor AC contactor coil KM1 remains energized; the time relay KT is energized to start timing, and when the set time is reached, the time relay normally open contact KT-1 is closed, and the running motor The AC contactor coil KM2 is energized, the main contact KM2-1 of the running motor AC contactor is closed, the running motor M2 is energized to start running, the normally open contact KM2-2 of the running motor AC contactor is closed, and the AC contactor coil KM2 of the running motor is energized to maintain running; the normally closed contact KT-2 of the time relay is disconnected, the AC contactor coil KM1 of the starter motor is de-energized, the main contact KM1-1 of the starter motor AC contactor is disconnected, the starter motor M1 is de-energized, the normally open contact KM1-2 of the starter motor AC contactor is reset, the time relay KT is de-energized and reset, and the normally open contact KT-1 and normally closed contact KT-2 of the time relay are reset; the running motor M2 runs, and the starter motor M1 operates when it is de-energized.

[0046] Running motor fault: The running current of the running motor exceeds the set value, the normally closed contact JD2-1 of the running motor protector is disconnected, the running motor AC contactor coil KM2 loses power (counting relay JS counts), the running motor AC contactor main contact KM2-1 is disconnected, the running motor M2 loses power, the running motor AC contactor normally closed contact KM2-3 is reset, the normally open contact JD2-2 is closed, the starter motor AC contactor coil KM1 is energized, the starter motor AC contactor main contact KM1-1 is closed, and the starter motor M1 is energized and started. When the motor starts running, the normally open contact KM1-2 of the AC contactor of the starting motor is closed, and the AC contactor coil KM1 of the starting motor remains energized; the time relay KT is energized for timing. After the set time is reached, the normally open contact KT-1 of the time relay is closed, and the AC contactor coil KM2 of the running motor is energized. The main contact KM2-1 of the AC contactor of the running motor is closed, and the running motor M2 is energized to start running. The normally open contact KM2-2 of the AC contactor of the running motor is closed, and the AC contactor coil KM2 of the running motor is energized and remains energized; the normally closed contact KT- 2 is disconnected, the starter motor AC contactor coil KM1 loses power, the starter motor AC contactor main contact KM1-1 is disconnected, the starter motor M1 loses power, the starter motor AC contactor normally open contact KM1-2 is reset, the time relay KT loses power and resets, the time relay normally open contact KT-1 and normally closed contact KT-2 are reset; the running motor M2 runs, and the starter motor runs without power; the running motor running current exceeds the set value again, the running motor protector normally closed contact JD2-1 is disconnected, and the running motor AC contactor coil KM2 loses power (counter The counting relay JS coil is energized, the counting relay normally closed contact JS-1 is disconnected), the running motor AC contactor main contact KM2-1 is disconnected, the running motor M2 loses power, the running motor AC contactor normally closed contact KM2-3 is reset, the normally open contact JD2-2 is closed, the starter motor AC contactor coil KM1 is energized, the starter motor AC contactor main contact KM1-1 is closed, the starter motor M1 is energized to start running, the starter motor AC contactor normally open contact KM1-2 is closed, and the starter motor AC contactor coil KM1 remains energized.

[0047] Starting motor failure: The running current of the starting motor exceeds the set value, the normally closed contact JD1-1 of the running motor protector is disconnected, the AC contactor coil KM1 of the starting motor loses power, the main contact KM1-1 of the AC contactor of the starting motor is disconnected, and the starting motor M1 loses power.

[0048] The starting motor runs alone: ​​the isolating switch QS4 is disconnected, the third circuit of the relay control part loses power, that is, the running motor control circuit loses power; press the start button SB2, the starter motor AC contactor coil KM1 is energized, the starter motor AC contactor main contact KM1-1 is closed, the starter motor M1 is energized to start running, the starter motor AC contactor normally open contact KM1-2 is closed, and the starter motor AC contactor coil KM1 remains energized.

[0049] Stop: Press the stop button SB1, the entire control circuit loses power, the main contact KM1-1 of the starting motor AC contactor is disconnected, the main contact km2-1 of the running motor AC contactor is disconnected, and the pump stops running.

[0050] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0051] Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. The double motor energy-saving device for oil pumping unit is characterized by: It includes a starting motor, a running motor, a motor control cabinet, a reduction mechanism and an oil pump; the motor control cabinet controls the starting motor to start, and drives the oil pump to do up and down reciprocating motion through the reduction mechanism; after running for a set time, the motor control box controls the running motor to start, the starting motor stops, and the running motor drives the oil pump to do up and down reciprocating motion through the reduction mechanism.

2. The dual-motor energy-saving device for oil pumping units according to claim 1 is characterized in that: The starting motor and the running motor are installed on both sides of the speed reduction mechanism; the starting motor is configured according to the starting power of the oil pumping unit specifications; and the running motor is configured according to the running power of the oil pumping unit specifications.

3. The dual-motor energy-saving device for oil pumping units according to claim 1 is characterized in that: The motor control cabinet has related operation and protection functions such as starting, stopping, overloading, phase loss, stalling, short circuit, overvoltage, undervoltage, leakage, three-phase imbalance, etc. of the starting motor and the running motor.

4. The dual-motor energy-saving device for oil pumping units according to claim 3 is characterized in that: The motor control cabinet is respectively equipped with a starting motor compensation capacitor and a running motor compensation capacitor.

5. The dual-motor energy-saving device for oil pumping units according to claim 2 is characterized in that: There are three simplified ways to equip the starting motor and the running motor: the first is a dual-power motor that is designed and manufactured in an integrated manner for the starting motor and the running motor; the second is a dual-speed motor with changed pole pairs; the third is a Y-Δ motor; the high-power wiring is used as the starting motor, and the low-power wiring is used as the running motor.

6. The dual-motor energy-saving device for oil pumping units according to claim 1 is characterized in that: The motor control cabinet controls the starting motor and the running motor, including the following steps: Step 1) Press the start button of the motor control cabinet to start the starter motor, driving the pumping unit to reciprocate up and down; Step 2) After the starting motor runs for a set time, the motor control cabinet starts the running motor; Step 3) The motor control cabinet stops the starting motor, and the running motor drives the pumping unit to do up and down reciprocating motion; Step 4) After the running current of the running motor exceeds the set value, the motor control cabinet stops the running motor and starts the starter motor to drive the pumping unit to do up and down reciprocating motion; Step 5) repeating steps 2), 3) and 4); Step 6) the motor control cabinet issues an alarm indicating that the well condition has changed; Step 7) When the running motor has phase loss, short circuit, overvoltage, undervoltage, leakage, or three-phase imbalance, the motor control cabinet stops the running motor and starts the starter motor to drive the pumping unit to reciprocate up and down; Step 8) the motor control cabinet issues an alarm indicating a motor failure; Step 9) When the starting motor is overloaded, lacks phase, is blocked, short-circuited, over-voltage, under-voltage, leaked, or three-phase unbalanced, the motor control cabinet stops starting the motor; Step 10) the motor control cabinet issues a starter motor fault prompt alarm; Step 11) Press the stop button on the motor control cabinet to stop the running starting motor or running motor.

7. The dual-motor energy-saving device for oil pumping units according to claim 6 is characterized in that: There are three ways to implement the control steps of the motor control cabinet: the first is to use a variety of relay control circuits; the second is to use a PLC control system; and the third is to use a single-board computer system.

8. The dual-motor energy-saving device for oil pumping units according to claim 7 is characterized in that: The three implementation methods of the motor control cabinet control step all have remote transmission interfaces for starting the motor and running the motor operation data and alarm status, and remote start and stop interfaces for the motor control cabinet.

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