What is internal overvoltage?

Internal overvoltage is due to the operation (switch,switch) accident (grounding,bolt,etc.) or other reasons,cause sudden changes in the state of the power system,there will be a shift from a steady state to another steady state transition process,the system may be produced in the process is in danger of overvoltage,the overvoltage is within the system caused by the electromagnetic energy buildup of oscillation and,so called internal overvoltage.It can be divided into operating overvoltage and resonance overvoltage,the former is generated single phase induction motor by system operation or fault,which is in the grid cell capacity and inductance components in grid (especially with iron core of ferromagnetic inductance components),parameters of unfavorable combination resonance.Because impact relay action is to rely on impact current,the launch of the signal () to accuse or accident signal circuit action,to make impact relays XMJ repetitive movements,namely the requirements after the first pulse signal action immediately return,ready for action again.

At this point if you don't add the keep circuit,pulse signal disappears,electric motors 12 volt sound (buzzer or alarm) will end immediately.Issued in order to guarantee reliable sound signal,without impact relay XMJ back and stop,so in startup sound in the middle of the relay circuit with a stay.Operation at execution time because the guardian,the guardian hands perform operation shall not exceed a.Sequence of operation shall not be temporary.Each perform a,the guardian is responsible for the inspection before permanent magnet generators for sale operation after location and preparation of votes,people listened to correct after the operation,the guardian operations are executed immediately.Each performed in red ink.Performed the operation ticket cover chapter executed,save for three months,the director of the substation should check once a month operation. In the following situations power capacitor should be work out immediately,and report the scheduling: (1) the power capacitor explosion; (2) joint serious overheating or melt; (3) casing put serious lightning collaterals; (4) capacitor serious injection or fire; (5) www.facebook.com/dongfeng.motor more than 40 ℃ ambient temperature.

Early study of permanent magnet synchronous motor

Early study of permanent magnet synchronous motor mainly in fixed frequency power supply of the working characteristic of the permanent magnet synchronous motor research,especially the research of steady-state characteristics and direct starting performance.Permanent magnet synchronous motor starting directly depend on damping windings provides asynchronous torque motor speed up to close to synchronous speed,and the magnetic resistance torque and torque will be synchronous motor pull in sync.V.B.H onsinger and M.A.R ahman et al.A lot of research work has been done in this single phase capacitor start induction motor respect.In the eighty s,foreign to inverter power supply of permanent magnet synchronous motor for further research.Inverter power supply of permanent magnet synchronous motor with direct starting of the structure of the permanent magnet synchronous motor are basically the same,but in most cases without damping windings.Damping winding has the following characteristics: first,damping winding to generate heat,make the permanent magnet temperature rise; Second,increase the moment of inertia,damping winding motor moment of inertia ratio decline; Third,the tooth of the damping winding make pulsating torque increases.

In inverter power supply situation,it will affect the original characteristics of permanent magnet synchronous motor,the steady state and transient characteristic of permanent magnet synchronous motor with a constant frequency compared with different features.A large number of papers published after 1980 study the mathematical model of permanent magnet synchronous motor,the steady state characteristics,dynamic characteristics.A.V.G umaste research such as the voltage type inverter power supply of permanent magnet synchronous motor steady state characteristics and the current type inverter power supply of permanent magnet synchronous motor steady-state characteristics.With the constant improvement of the permanent magnet synchronous motor speed control system performance requirements,the perkins diesel generator need to design high efficiency,high moment of inertia ratio,high energy density of permanent magnet synchronous motor,G.R.S lemon and others diesel generator for speed control system dynamic performance and high efficiency requirements quickly,modern design method of permanent magnet synchronous motor is presented.With the development of microcomputer technology,permanent magnet synchronous motor vector control system of full digital control also has made great development.D.N aunin a permanent magnet synchronous motor is developed,such as right amount control system,using a 16 bit single chip microcomputer 8097 as control computer,realizes the high accuracy,high dynamic response of full digital control.In the late eighty s,early ninety s B.K.B ose and published a large number of permanent magnet synchronous motor vector control system of full digital control of the paper.

Speed controller of permanent magnet synchronous motor vector control system usually adopts proportional integral (PI) control.PI controller has a simple structure,good performance and is not sensitive to controlled object parameters change,etc.In 1991,R.B.S epe adopts self-tuning control in the speed controller for the first time.Early adaptive control is mainly used in dc motor adjustable beam system.National Taiwan university tian-hua liu and so on for the first time the robust control theory is applied to permanent magnet synchronous motor servo drive.Motor in the process of running,the model and the parameter is constantly changing,the change of the parameters and model will cause to reduce the performance of control system.All kinds of robust control technology in modern control theory to make the control system in the model and parameter changes to protect the good control performance.Will,therefore,all kinds of robust control technology used in motor speed regulation,can greatly improve the performance of speed control system.In this regard,the use of more successful control technology mainly include: adaptive control,variable structure control,parameter identification technology,etc.