The working principle of the ac contactor

Electromagnetic suction when energized coil,the static iron core,will be moving iron core and,as a result of the contact system is with the linkage of moving iron core,so core to drive three move contact run at the single phase electric motor same time,the contact closure,and connected to the power supply.Disappear when power coil,suction,moving iron core linkage part rely on spring reaction and separation,make the main contactor disconnect,cut off power supply.The choice of ac contactor:(1) the continuous operation of equipment.Contactor calculate by 67-75%.The 100 - a ac contactor,can control the maximum rated current is 67-75 - a the following equipment.(2) uninterrupted operation of equipment.Contactor calculate by 80%.The 100 - a ac contactor,can only control the maximum rated current is 80 a the following equipment.(3) and short- time working equipment.Contactor calculate by 116-120%.


The 100 a ac contactor,can only control the maximum rated current is below 116-120 - a device.Consider the work environment electric motors 12 volt and the structure of contactor.Also shows that:as the market competition is intense,to reduce the cost of domestic some manufacturer,has been in the corners,for example:in the coil production reduce wire diameter less number of turns around,even in touch head is not in conformity with the national standard of the material or thickness and the cross section is not ac electric motors enough.This kind of circumstance is not only reflected in the contactor,on top of other products such as short as well.Cause in be used actually,mark is 100 a contactor or short circuit,the actual load can only be even lower in 80 a,high failure rate.Popular theory is:so,now have to use domestic low-end products,to the rated capacity of 7 discount according to the www.facebook.com/dongfeng.motor nameplate instruction to use!

Motor USES the application

Is the most widely used in all kinds of motor ac asynchronous motor (also known as induction

motor).Is it convenient to use,reliable operation,low cost,firm structure,but power factor is low,speed is also more difficult.220v ac electric motors The large capacity of low speed synchronous motor is commonly used engine motor motor (see synchronous motor).Synchronous motor power factor is high,and its speed has nothing to do with the size of the load,only depends on the power grid frequency.Work more stable.In wide scope use dc motor speed control occasions.But it has a commutator,the structure is complex,expensive,maintenance difficulties,not suitable for bad environment.Since the 1970 s,with the development of Motor vehicle power electronic technology,ac motor speed control technology is mature,equipment increasingly lower prices,already applied.

Motor work in the prescribed format (continuous duty system,short-time duty system,intermittent cycle) can assume and will not cause the maximum output mechanical power of the motor overheating is called its rated power,should pay attention to when using the provisions of the nameplate.Must be noticed when the motor running to make it match the load characteristics and the characteristics of the motor,avoid www.facebook.com/guohong.trading coasters or shut down.Electric function provides a large range of power,class from milliwatts to kilowatts.The use of the motor and control is very convenient and has since starting,acceleration,braking,reverse and stopper live ability,can meet various operation requirements; The work efficiency of the motor is higher,and without dust,smell,no pollution,noise is small.Because of its series of advantages,so in industrial and agricultural production,transportation,national defense,commercial and household appliances,medical electrical equipment and so on various aspects are widely used.General 220v ac electric motors motor drive its output power will change with the rotational speed.

The cause of the motor open phase have?

Power supply:(1) the switch contact undesirable;(2) transformer or line break;(3) the safety

fuse.Motor:(1) motor terminal box screw loose poor contact;(2) the internal wiring bad welding;(3)

the motor winding wire break.What are the induction motor sales causes of abnormal vibration and sound? Mechanical aspects:(1) poor lubrication bearing,bearing wear;(2) bearing chamber www.dongfeng-motor.com is too large.(3) fastening screw loose;(4) motor with sundry.Electromagnetic aspects:(1) the motor overload operation;(2) three phase current balance;(3) lack of phase,(4) of the stator,rotor winding short- circuit fault;(5) caused by the welding part of the open welding of cage rotor broken bar.What are the cause of the motor bearing overheating?

The motor itself:(1) the bearing inner and outer ring with tight;(2) parts shape tolerance has a problem,such as frame,end cover,shaft parts alignment is bad; (3) bearing improper selection;(4) bearing or bearing cleaning not net,poor lubrication grease with sundry;(5) the shaft current.Use: pumps (1) improper installation,such as the motor shaft and the drive device of the shaft alignment of undesirable;(2) pulley pulled too tight; (3) bearing bad maintenance,insufficient or grease,could more than dry deterioration.The motor insulation resistance low what are the reasons?(1) winding be affected with damp be affected with damp or water invasion;(2) winding on accumulation of dust or oil;(3) insulation aging;(4) motor wire or wiring board insulation damage.

Electrician training of motor working principle and the composition of the work

A. the motor operation of work: Now more commonly used mainly by ac motor, it can be divided into three phase asynchronous motor, single phase ac motor, two of the former is more used in industry, and then a usually used in civil electrical appliances. Look from the structure of the motor, mainly divided into the control part and execute drive part and control part is mainly composed of three-phase PWM www.facebook.com/dongfeng.motor wave generator, single chip microcomputer, intelligent inverter, rectifier module, A/D module, fault detection, input and output channels, etc; Perform drive part mainly includes the three-phase motor and position sensor bar. B. the working principle of the machine Motor operation is working on the current and voltage motor part sensor and position sensor detection, draw A three-phase inverter module output current, voltage and the valve position signal, and then magnet generator by the A/D converted into single chip microcomputer. Single-chip microcomputer by controlling the effect of PWM wave generator, finally realize the operation control of the machine. Inverter modules work required by the rectifier circuit dc voltage signal to the whole bridge rectifier of 380 v power supply. For the analysis of the motor running, here mainly for industrial application of the principle of three phase asynchronous motor are discussed. Motor rotation is the basic working principle of the three-phase symmetric winding zhongtong people produce round rotating magnetic field, the three-phase current conductor cutting rotor rotating magnetic field induction electromotive force and the current, the rotor current carrying conductor in magnetic field by electromagnetic force, thus forming the electromagnetic torque, driving the motor rotor rotation.