At present, the screw pump widely uses the drive mode of electric motor belt transmissionreducer deceleration. Although it can conduct producing stablyeffectively, it exist problems of low transmission efficiency for gear reduction, large equipment volume, high failure rate, large noise, bad reliability as well as the troublesome parameter adjusting operation.

The ground drive system of the direct drive screw pump with permanent magnet brushless DC motor developed by our company has the advantages including stable operation, good effect of energy saving, low operation expense, low noise, convenient managementextremely minimum maintenance workso on after nearly two years of operation.

The main technical indexes of the ground system of the direct drive screw pump with electric motor produced by our company are as follows:

Power factor of the electric motor95%

System efficiency90%

Rated temperature rising55℃ (Rated load, continuous work)

Starting torque: Three times of the rated torque per minute

Adjustment range of the rotation speed: 0—100% rated rotation speed

The intelligent controller is composed of three parts including rectifyingwave-filtering, intelligent calculationlogic control & power unit.

The direct drive screw pump developed by our company has the following characteristics:

1、The structure of the transmission system is simple, reasonable, high efficient. It can save energy by 30%.

The structure of the ground drive system of the direct drive screw pump is very simple, reasonablehas high efficient transmission. The direct drive screw pump abolishes the reducerbelt transmission equipment of the traditional mechanical screw pump. The motor adopts verticalhollow axis structure. The transmission form between the motorthe screw pump is direct co-axisconcentricity transmission with the efficiency nearly 100%, which increases the mechanical efficiency of the whole system by 30%, decreases failure rate of the machine by 90%, decrease the maintenance work by more than 90%,prolongs the life of the equipment.

The operation cost decreases a lot.

2、Specially designed direct current permanent magnet brushless torque motor with high efficiencylow speed, high power factor

The direct current permanent magnet brushless torque motor, witch adopts the rare permanent magnetic rotor with high field intensity has high power factor. It is 5%-12% higher than the asynchronous motor with the same volume. The motor has the advantages of large torque, small volumelight weight. The propertiesliability have been greatly improved.

3、The starting torque of the low-speed direct current permanent magnet brushless torque motor is large. Starting power reserves are no needed.

The low-speed direct current permanent magnet brushless torque motor has the characteristic of constant torque with the starting torque being 3 times of the rated torque per minute. It corresponds with the starting characteristics of the screw pumpis in favor of the cost reduction. In comparison with the asynchronous AC motor, the energy saving effect is 2-5%. The motor has soft external characteristicsthe starting torque reaches 3-4times of the rated torque, which has incomparable advantage over other productsasynchronous AC motors.

4、Low lossless heat of the motor

The motor adopts high-quality iron core materialoptimized magnetic circuit, structurewinding design. It reduces the copper lossiron loss as much as possible under the condition of giving attention to the cost. Many measures have been taken which make the energy saving effect of the system reach 20-40%the temperature rising no higher than 55℃.

5、Anti-reversion by electromagnetic hamperdynamic braking

Combining with the traditional braking unit, the anti-reversion control algorithm by electromagnetic hamper originally created by our company realizes the electronic anti-reversion control. It releases the elastic torque of the sucker rod slowlycompletely,which is helpful for the start-up of the system. Meanwhile, it also improves the safety performancecan effectively avoid the occurrence of mechanical accident such as crack of the pump rod.

6、Heat dissipationanti-reversion control of the electric motor with large torque system

The DC motor still adopts the structure without fan. We carried out the optimal designselection of the magnetic circuit, groove type, winding data, iron core material for the electric motor,carried out the optimal design for heat reductionthe reinforcement of the heat dissipation effect. In aspect of anti-reversion control, we created initially substitution type anti-reversion control mode, that is, electromagnetic hamper braking unit dynamic braking” which makes the anti-reversion system more reliable.

The direct drive