The Research Of Disc-type Electromagnetic Buffer

At present, weight metering type device in which there is a symmetrical dump is commonly used among the oil metering equipment in the oilfield. The rack of device and oil tank will have a significant impact from the dump's turning. It will affect not only normal operation of the device, but also will cause damage to the device and will make a lot of noise.The tridditional buffer device includes buffer device with springs and that with hydraulic pressure, we have designed a Disc-type Electromagnetic Buffer. Compared with the mechanical brake, it has the characteristics of having high reliability, superior auto-regulatory and small dependence on the environment.The brand new buffer device took the revolving shaft of the tripping bucket into the rotor of the permanent-magent generator.As the tripping bucket inverts,the generator created electromagnetic torque which triged the movement of the tripping bucket to reduce the impact force. The brand new buffer device had a nice follow-on characteristic.To get a perfect electromagnetic torque, resistances was be tandem connected in the external circuit of the stator windings.Adjusting the resistances value could change the current of the windings,and then could change the electromagnetic torque.First,in the article,a model of the tripping bucket was established by which the troque and speed of it was analysed.The generator was preliminarily designed based on the troque and speed.Then,binding the characteristics of Buffer and the DPMSG, the paper analyzes the basic theory of the DPMSG used as Buffer and establishes its steady-state equation from which its power and torque balance equation is derived. Based on the structure and characteristics of it, the paper introduces the idea of design, main dimensions, the structure of tooth and slot of stator, winding arrangement and the structure of magnetic circuit.Finally,by using the finite element analysis software-Maxwell2D introduced by Ansoft company, the paper works out the dynamic simulation of the electromagnetic torque and rpm of equivalent model of Disc-type Electromagnetic Buffer which is a permanent magnet synchronous generators. The dynamics torque calculated from the physical model of device is compared with above results and analyzed. The result shows that the electromagnetic torque generated by buffer can effectively absorb the kinetic energy produced by the device, and the can reduce the impact caused by dump on the rack of device and oil tank.