Measuring rotor winding connection is wrong use method of failure

 Put the rotor under small electric fan motor test in a test in the mouth,use the turn-to-turn short circuit tester electricity,tester within the closed magnetic circuit core and rotor core has alternating magnetic flux.Multimeter is 10 v ac voltage profile,wholesalemotor.blogspot.com adjacent commutator segment and commutator segment,every piece of commutator segment,every two pieces of commutator segment,every three to every more pieces commutator segment between the voltage value.Rotor winding connection correct voltage size should electricalmotor1.blogspot.com be consistent,if you have below normal,it is possible that some components lead to reverse,with the fault of rotor winding to repair to meet again. "Little experience" Described above with a multimeter ac 10 v voltage profile measuring voltage between adjacent the commutator segment,as there are below normal,should turn the rotor position,and then look at the voltage value,so as high efficiency electric motor to avoid miscalculation.If still below normal,should be cleaned of mica slot commutator conductive material (such as charcoal powder),then test again,in order to avoid miscalculation.

Rated current of the three-phase ac motor is calculated

Rated current In = Pn/(1.732 * cos phi n * Un acmotortrading.blogspot.com eta).Type of Pn for the nominal power rating,the Un as the rated voltage,cos phi n as the rated power factor,eta rated electric motors 12 volt operating efficiency.Note that the power refers to the output shaft power,Pn/eta is the electrical power input.3 power rating =),rated voltage,rated current,efficiency,5kw permanent magnet generator power factor,the apparent power = rated voltage,rated current,apparent power is equal to mini electric motor the vector and active power and reactive power,power rating is refers to the mechanical output at rated power.

The principle of three phase asynchronous motor

Creates a to synchronous speed n1 along the circle space inside the stator and rotor rotate clockwise rotating magnetic field. Due to the rotating magnetic field in the n1 speed rotation, ac induction motor the rotor conductor is still at the beginning of the rotor conductor will cut the stator rotating magnetic field and produce inductive www.facebook.com/dongfeng.motor electromotive force (judge the direction of the induced electromotive force with the right-hand rule) due to the rotor conductors sub is short circuit loop at each end, and the effect of induction electromotive force, the rotor conductors will occur basic consistent with the direction of induction electromotive force induced current. Rotor current ac synchronous motor carrying conductor in the role of the stator magnetic field by electromagnetic force (force in the direction of the left hand rule determine) electromagnetic force on electromagnetic torque, rotor shaft drive rotor spinning in the direction of the rotating magnetic field. By analyzing the working principle of the motor can be summarized as follows: when the three-phase stator winding of the motor (the difference between a 120 - degree Angle) to the balanced three-phase alternating current (ac), will happen in a rotating magnetic field, the rotating magnetic field cutting rotor winding, which occur in the rotor winding induced current (rotor winding is closed-cycle) rotor of current-carrying conductor in the stator rotating magnetic field under the action of electromagnetic force will occur, as to form the electromagnetic torque on the motor shaft, motor rotation, and the motor rotation direction is the same as the rotating magnetic field direction.

Three-phase asynchronous motor speed control method

Three-phase asynchronous motor's very logarithmic p and s slip can be too much to change speed. From the perspective of the nature of speed regulation, different ways of governing is nothing but change synchronous ac motor synchronous speed or not turn two. Widely used in the production of machinery is not the change in speed control method of synchronous speed of wound rotor motor rotor series resistance speed governing, chopping speed regulation, cascade speed regulation and application of the electromagnetic slip clutch, hydraulic coupling, such as oil film clutch speed regulation. Changes of the synchronous speed logarithmic multi-speed motor, stator can change of the stator voltage, frequency, frequency control of motor speed has no commutator motor speed regulation and so on. From energy point of view, when there is high speed control method and low speed control method of two kinds: an induction refers to the effective speed control is constant, so there is no slip loss, such as multi-speed motor, frequency control of motor speed and slip loss can be recovered speed control methods (such as cascade speed regulation, etc.). Have slip loss speed regulation method belongs to the low speed, such as rotor series resistance speed control method, the energy loss in the rotor circuit; Electromagnetic clutch speed regulation method of energy loss in the clutch coil; Hydraulic coupler speed regulation and energy loss in the oil of hydraulic coupling. In general slip loss increases with expanding range of speed regulation, if the speed range is not big, energy loss is small. This control method is used to change the stator winding of red way to change the cage ac motor stator polar logarithmic to achieve speed, features below: With a hard mechanical properties, good stability; No slip loss, high efficiency; Wiring is simple, convenient control, low price; Have used differential is bigger, cannot obtain smooth speed regulation; Can be used with regulating speed control, electromagnetic slip clutch, smooth speed characteristics of high efficiency. 

This method is suitable for don't need a stepless speed regulation small electric motors of production machinery, such as metal cutting machine tools, elevators, lifting equipment, fan, water pump, etc. Cascade speed regulation refers to the motor rotor winding circuit in series with adjustable additional potential to change the slip of the motor, to Motor vehicle achieve the purpose of speed control. Most of the slip power is absorbed by series of additional potential to recycle produce additional device, the absorption of returning the slip power grid or conversion of energy use. According to the slip power utilization way, cascade speed regulation can be divided into Y series three-phase asynchronous motor cascade speed regulation, mechanical cascade speed regulation and thyristor cascade speed regulation form, adopts thyristor cascade speed regulation, its characteristic is: Slip loss in the process of speed regulation can be back to the grid or production machinery, high efficiency; Installed capacity is proportional to the speed range, the investment province, apply to speed range in production machinery from 70% to 90% of the rated speed; Speed regulating device failure can switch to run at full speed, avoid production; Thyristor cascade speed regulating power factor is low, the influence on harmonic. This method is suitable for the fan, water pump and the rolling mill, mine hoist, the extrusion machine use. Frequency control method Frequency control of motor speed is to change the frequency of the motor stator power, to change its synchronous speed control method. Variable frequency speed regulation system is the main equipment to provide frequency conversion power of inverter, the inverter can be divided into ac - dc - ac frequency converter and ac - ac frequency converter two kinds big, cross - straight - to pay inverter are mostly used in China at present. Its features: There is no additional loss of high efficiency and speed the process; Application range is wide, can be used in the cage type asynchronous motor; Large range of speed regulation, and the characteristics of hard and high precision; Technology is complex, high cost, maintenance difficulties. This method is suitable for the requirement of high precision, better speed control performance.

Permanent magnetic synchronous permanent magnet synchronous motor motor application prospect

Visible, dc thoughts have excellent authorized functions, its mechanical characteristics and speed characteristics are parallel lines, this is the characteristics of all kinds of switch electric thoughts have not. In addition, in fact, permanent magnetic iron remover. Dc current idea and starting torque, high efficiency, speed control, good static characteristic features such as easily. Good duty characteristics make dc thought for a long time before the 70 s, in the situation of speed regulation, duty supplications, nearly became a unique selection. However, direct current (dc) thought the authority of the fluff, the field winding on the stator attacks the main magnetic field, the large dc power idea often also equipped with commutating ac electric motor parts pole, in order to improve of the reversing of the motor function. Dc motor armature winding and been planted on the rotor commutator, dc power supply through the brush and commutator will direct current to the armature winding translates into alternating current in the armature winding, namely mechanical current commutation. Tumultuous authority limit the dc thought to further reduce the volume and weight, is double brush and commutator of the sliding contact caused by mechanical wear and spark, the direct current idea obstacle, the more trustworthy authenticity is low, life is short, cherish the maintenance of large amount of doing things. Commutation spark both the commutator of electric corrosion caused by nuisance source, or a radio will be harmless influence on the surrounding electrical equipment. Motor capacity, rotational speed is higher, the greater the subject becomes more important. 

So, in fact, permanent magnetic chuck. Ordinary direct current thoughts of brush and commutator limits the thoughts to burning with high speed, large capacity, depression and goods. On the switch power grid, people still usually manipulated exchange asynchronous electrical idea to drag xing machinery. Simple exchange asynchronous electrical thought has no authority, trustworthy real and long service life, low capital, cherish the simple maintenance. Compared with direct current (dc) idea, however, its speed control function is poor, small starting torque, overload talent and low efficiency. Carnegie-give must be the onset of a rotating magnetic field from the grid reactive power, so the power status is low, especially when the light load, which adds lines and large power consumption. Permanent, since you know that a strong permanent magnet. Without beg speed control of the situation, such as fan, water pump, the common machine tool drive, asynchronous electric thought according to a leading fame, of course, this type of drag, visible in a large number of energy wastage. Domain before the electric drive, rarely color synchronous electric thoughts, learn to permanent magnetic iron remover. Its main cause motor fan is synchronous electrical thought cannot under grid voltage starting, movement of the rotor pole under the effect of rotating magnetic field, uniform torque is zero. They are also great frequency conversion power can solve the starting and speed control of synchronous motor was thought subject, but in the 70 s, variable frequency power supply of equipment are to think about. So, before the domain of electric drive, using synchronous motor was thought as the original thoughts is seldom seen. In high power within the boundaries, has no intention of occasional synchronous electric thoughts running example, but it is often used to improve power factor of power grid enterprises.