Due to the inherent characteristics of the four-bar linkage of the beam pumping units, although the torque balance reaches the industry standards, it still has many disadvantages, such as poor balance effect, bigger fluctuation of gearbox torque, existence of negative torque, lower work efficiency, bigger consumption of energy, phenomenon of "a big horse pulls a small carriage".
In locomotive traction system, unavoidable factors (such as idling and skidding) typically lead to the decline of traction performance of one or more motors, thereby resulting in the fluctuation of total torque traction amount.
Further analysis of the main flow phenomena and characteristics of scroll compression chamber at the discharge side during the discharge process confirms that under-compression and over-compression lead to the large variation of gas pressure and dramatic fluctuation of compression torque.
(e) The torque factor of the four-bar linkage is an important factor to determine the fluctuation of the gearbox torque curve.
This paper deals with the rattle noise, caused by the fluctuation of the engine torque (acyclic excitation) which, under special conditions, can cause multiple impacts inside the gearbox.
The instability regions, the vibration amplitude and the range of fluctuation of the driving torque for a double crank-and-rocker mechanism are illustrated graphically.
The presence of a clutch between the belt end-point and the source of torque fluctuations offers a means to clip torque fluctuations and thus to clip belt excitation.
Synchrophasor measurements are widely used for various monitoring, assessment and control applications such as state estimation [5], control of frequency fluctuation [6], torque angle control of rotor [7] etc.
For the beam pumping units, reduction of the polished rod load or the gearbox net torque is an effective method to improve its system performance, because the amplitude value and the fluctuation of the gearbox net torque reflect the running condition of this oil wells system.
