External Rotor Electric Motor Pumping Unit

Sanjack first applied the rare-earth permanent magnet motor with external rotor to the tower-mounted pumping unit. The pumping unit has the advantages of large lifting torque, stable operation, low noise and long stroke, etc.

  • 25 years External Rotor Electric Motor Pumping Unit manufacturing experience
  • The strictest quality standards on External Rotor Electric Motor Pumping Unit
  • Full support on your customised requirement

External rotor electric motor pumping unit is an electromechanical integrated tower pumping unit newly developed by Sanjack petro.

The whole system is composed of eight parts: external rotor motor, variable frequency control panel, unit frame, movable pulley group, counterweight, brake, and load-loss protection device, wire line, base, and so on.

It is a new type of pumping unit in the petroleum industry. Compared with the traditional walking beam pumping unit, it saves the gear reducer and crank, pitman mechanism, and improves the transmission efficiency.

external rotor electric motor pumping unit opeation manual

The unit frame works as the carrier of all the structure, the AC external rotor permanent magnet synchronous motor is the power source of the pumping unit.

The variable frequency control technology is used to control the motor positive and negative rotation and its speed.

rare-earth permanent magnet motor

1).Constant torque
2).Torque value up to 4500Nm
3).Can realize “ABS” positive and negative conversion
4).Intelligent temperature control switch

The external rotor, movable pulley, wire line and counterweight constitute the traction system. The sucker rod moves up and down through the flexible wire line.

The brake device installed outside of the external rotor can brake the unit in time when the motor stops to ensure safety.

As the gear reducer is saved, there is no high speed rotation part in the unit and the mechanical design is reasonable.

external rotor electric motor pump jac

In order to reduce the load of the power source and increase the driving force, a set of movable pulleys are equipped at the sucker rod end and the counterweight end respectively to make the equipment more energy-saving and efficient.

The whole unit has the characteristics of simple structure, small volume, long stroke, low frequency and convenient maintenance.

movable block

Variable frequency control program and auxiliary stroke switching device can effectively control the motor reversing movement and realize stepless adjustable speed of the motor.

Compared with the traditional beam pumping unit, it has the advantages of convenient adjustment of parameters.

external rotor electric motor oil well pump jack

The electrical control program has the functions of overload protection, phase-missing protection, motor overheat protection; short-circuit power-off protection, so that the equipment is more intelligent and safe.

Brake and loss of load protection device can play the greatest role in protecting the safety of personnel and equipment when the loss of load occurs.

In a word, external rotor electric motor pumping unit is a new type of electromechanical integration pumping unit with the characteristics of energy saving, emission reduction, safety and intelligence.
external rotor electric motor pump jack
It makes a good sale in ShengLi oilfield, ZhongYuan oilfield, LiaoHe oilfield, DaGang oilfield and Huabei oilfield, etc.

Working Principle

When the sucker rod is going up, the counterweight is less than the sucker rod load, and the motor rotates counterclockwise to output torque to help the counterweight lift the sucker rod;

When the sucker rod descends, the sucker rod load is less than the counterweight, and the motor rotates clockwise to output torque to help the sucker rod lift the counterweight.

The reciprocating movement of the sucker rod is realized by the periodic forward and reverse of the motor.

Since the counterweight is the average value of the maximum load and the minimum load, the positive and negative rotation work of the motor is basically equal.

working principle of pumping unit


Conventional oil
Deep wells
Thermal wells
Light, medium, and some of heave crude
Vertical, slant, deviated, and some of horizontal well application
Dewatering natural gas and coalbed methane
Operations requiring energy savings
Operations requiring lower noise (only 48 decibels, the ultra-low-noise design is suitable for a quiet environment.)
Wells that experience frequent downhole equipment failures because of friction.

Product advantage

1. Power saving: Compared with conventional beam pumping units, the average power saving rate is up to 30%.
2. Efficiency improvement: Compared with conventional beam pumping units, the production efficiency can be increased by 30% on average.
3. Noise reduction: Since there is no intermediate deceleration mechanism, the noise is low. The measured noise is below 40dB.
4. Deep well production: especially suitable for operations requiring long stroke, low stroke and deep pumping with small pump.
5. Space saving: especially suitable for high density of small space.
6. Easy to operate: 0-3 times stepless adjustment can be achieved in the adjustment of stroke, and 0-12 meters can be customized according to user requirements.
7. Simple and convenient maintenance: The conventional beam pumping unit has as many as 35 fault points, and the machine has only 6 maintenance points.

Model WCYJW12-6-3.8Z WCYJW14-6-4.5Z
Stroke(m) 1~6 1~6
SPM(min-1) 3 3
Polished rod load (kN) 120 140
Rated torque(kN•m) 3.8 4.5
Outline size(m) 4.35×2.3×11.84 4.35×2.3×11.84
Rated voltage(V) 380 380
Rated power(kW) 18.5 22
Rated rev(rpm) 48 48
Insulation class F F
Classification condition Long stroke  ow SPM

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