Ac servo motor control

The structure of the dc servo motor as the common dc motor,and is done in order to reduce the moment of inertia of long and thin.It's exciting winding and armature respectively by two independent power supply.There is also a permanent magnet,namely the pole is a permanent magnet.Usually adopt the armature control,that is,f certain excitation voltage,establish flux is also a constant value,and the control voltage in the armature Uc,institutional characteristics of the dc servo motor (n = f (T)) and dc separately excited motor,three-phase asynchronous motor under different control voltage (Uc control voltage rating) of mechanical characteristic curve.By the graph is: under certain load torque,when magnetic flux unchanged,if the rise in the armature voltage,the electric vehicle motor speed of the motor is higher; On the other hand,the lower the armature voltage,speed dropped; When Uc = 0,motor immediately halt.To motor reversal,can change the armature voltage polarity.Compared with dc servo motors and ac servo motor,it has mechanical properties is stiff,the output power is larger,rotation,large starting torque,etc The normal operation of the servo motor,as long as out of control voltage,the motor stop immediately.

When servo motor loss control voltage,it is in single phase operation state,due to the rotor resistance is big,the rotation of the two opposite directions in the stator rotating magnetic field and rotor effect produced by the two torque characteristics (T1,T2 S1 S2 curve) and synthetic torque characteristics (t-s curve,with the ordinary single-phase asynchronous motor torque characteristics (T '-s curve).Then the synthesis of torque T is the brake torque,so as to make the motor stop quickly.Servo motor is single-phase runtime mechanical characteristic curve.A certain load,the control voltage Uc,the higher the speed is higher,in the control voltage,load,speed down.The structure of the ac servo motor stator is basically similar to capacitance split-phase single-phase asynchronous motor.On the stator winding with two position difference of 90 ° to each other,one is Rf excitation winding,it always pick on the ac voltage Uf; L,another is the control winding connection control signal voltage Uc.So is also called the two ac servo motor servo motor.wholesalemotor.blogspot.com Hollow cup rotor servo motor structure without control voltage ac servo motor,the stator is only produced by the pulse excitation winding magnetic field,rotor motionless.When a control voltage,stator and then produce a rotating magnetic field,the rotor rotate along the direction of the rotating magnetic field,in the case of constant load,the speed of the motor changes with the size of the control voltage,when the control voltage of opposite phase,servo motor will be reversed.

The output power of the ac servo motor is 0.1 100 w.When the power supply frequency 50 hz,voltage is 36 v,110 v,220,110 v; When the power supply frequency is 400 hz,the voltage have 20 v,26 v,36 v,115 v,etc.Ac servo motor smooth operation,low noise.But control characteristic is nonlinear,and the rotor resistance is big,loss is big,efficiency is low,so compared with capacity of Y series motor,big volume,heavy weight,so is only applicable to 0.5 100 w small power control system.The working principle of ac motor fan servo motor with split-phase single- phase asynchronous motor,though similar,but the rotor resistance of the former is much larger than the latter,so compared with the single asynchronous motor,servo motor has three significant characteristics,due to the rotor resistance is big,the torque characteristic curve 1,with normal asynchronous motor torque characteristic curve,compared to 2 a significant difference between the two.It can make the critical slip S0 > 1,this not only makes the torque characteristic closer to linear mechanical properties,and has a large starting torque.Therefore,when the stator's a control voltage,rotor rotating immediately,which has the characteristics of starting fast,high sensitivity.The rate in the range of 0 to 1 S servo motor can stable operation.

High voltage motor stator coil damage problem Electrical engineers

General electrical engineer pointed out that the long-term operating experience and motor stator winding accident phenomenon indicates that the generator and high voltage motor stator coil corrosion damage phenomenon is quite common,seriously affect the safe operation and service life of the motor.A,corrosion characteristics and parts of motor stator coil From the high voltage motor stator winding coil main insulation breakdown phenomenon,the main coil corrosion damage of the insulation can be roughly divided into two classes: class starts to coil outside the main insulation inner corrosion damage,often referred to as corrosion;Another kind began to coil internal insulation outside corrosion,commonly referred to as internal corrosion.1.1 main coil insulation outside corrosion damage (1) motor stator winding end inside the stator core and coil vibration,the primary coil insulation corrosion damage.This is the most common corrosion damage accident is also one of the most serious phenomenon.Cause this is the main reason of the corrosion damage,the motor in operation,because of its department of winding vibration under the action of electromagnetic force,the coil in the stator core groove end fixed not firm,article slot wedge,the line between layers of cushion,loose end interval block and tied the rope off,coil and lashing and friction within the interval between block,anticorona lacquer semiconductor corona corrosion damage,resulting in slot and end coil main insulation breakdown.

(2) the stator core wear corrosion of the internal magnetic materials.This kind of situation is mainly due to the maintenance process without careful cleaning and purging of the stator winding,causing the windings cracks and other corner place left some tiny magnetic sundry,when the motor running magnetic debris was adsorbed on the surface coil insulation Lord,under the action of electromagnetic induction and electromagnetic force,magnetic impurities in rotation movement,grinding main coil insulation to drill a hole.(3) of the stator coil corrosion of oil.At present,a large generator and high voltage motor bearing shell are widespread leak phenomenon,thus the motor coil for burning oil corrosion accidents are quite common.Parts of the basic focus of this kind of failure at the end of motor stator slot,winding and winding nose leads.Are attached to the coil is characterized by the oil,to dissolve erosion effect to the main coil insulation,main insulation and conductor is layered whole coil insulation strength is reduced,after long time running and stator winding short circuit,grounding short circuit fault,etc.(4) the stator core silicon steel sheet of corrosion wear of the insulation.If in the process of being connected in the stator iron core,silicon steel sheet laminated,irregular or stator core ventilation channel and the end pressure refers to fixed installation,or damage to the stator core in the repair,will cause the vibration occurs when the motor running,wear insulating,eventually resulted in the breakdown of the main insulation of wire coil.

1.2 coil corrosion Multiple accident statistics and fault coil autopsy results show that the coil internal corrosion is more serious.Corrosion inside the large coil anatomic analysis showed that the corrosion is generally from insulation and conductors in the air gap between the air bubbles,coil straight line and the end of the R Angle,coil lead off line welding etc.Corrosion phenomena within the first coil internal insulation to bleach and gradually expand,then burning insulation form hole and a large number of green powder,so as to accelerate and main corrosion damage of the insulation between wire strands,until the main insulation breakdown.In addition,the high temperature caused by the thermal aging is also an important factor to the internal corrosion.Second,the coil reason analysis of internal and external corrosion Motor stator coil of the internal and external corrosion reasons,mainly due to the main coil insulation in the motor running,long-term in electromagnetic vibration,high temperature and high voltage under the action of three kinds of factors and vibration wear,corona corrosion and thermal insulation aging,make whole coil insulation shell,layered,burning,wear and dielectric strength reduce wait for a phenomenon,resulting in insulation breakdown of failure.

Electromagnetic vibration wear corrosion (see electrical engineer) In the operation of the motor in produce all kinds of mechanical vibration,wear out coil insulation,corrosion is one of the main electromagnetic vibration on the motor end winding and the influence of notches.If the stator core installation quality is bad,bad winding end binding process,make the coil in the groove by fixed bad,produce great vibration amplitude,article water pump interlayer pad and temperature measuring element pads in the lower level to HuiCuan move between coil and wear on the lower layer coil,the coil main insulation damage.Is more serious is that,if in the operation of the coil wire through the current 2 times frequency electromagnetic vibration,will not only make the coil and iron core and winding end interval block vibration,make the main insulation surface wear,but also can make the wire with the main insulation between the friction between interturn,shares of the wire vibration,causing wire interturn,loose,short circuit,break between the shares.At the same time,the additional loss and the temperature rise in short circuit,will accelerate local main insulation ageing,reduce the dielectric strength,even under normal working voltage insulation breakdown caused by failure.Therefore,the electromagnetic vibration is caused by coil outside the main insulation 8500w gasoline generator corrosion and the main cause of the corrosion damage.