Synchronous motor and three-phase asynchronous motor

difference:1,the biggest difference between synchronous motor and three-phase asynchronous motor is to look at his door of rotor speed is consistent with the three phase generator speed of the stator rotating magnetic field,if the rotation speed of the rotor and stator is the same,that is called synchronous motor,if inconsistent,call three phase asynchronous motor.2,when a logarithmic must have strict relationship between the speed and frequency of the motor,with electrical engineering terms,is the synchronization. Three-phase asynchronous motor is also called induction motor,mainly used as a motor,the rotor speed is always less than synchronous motor at work.3,the so-called "synchronization" is the armature,stator winding through the current,will form a rotating magnetic field in air gap,and the direction of rotation of the magnetic field and rotor electric motor laminations rotating speed and

steering,rotational speed,the same reason for synchronization.Three-phase asynchronous motor,the

rotating magnetic field and rotor relative speed,namely to produce torque.As to why three-phase

asynchronous motor and synchronous motor the opportunity to have such a distinction,to sum up,I have the most fundamental reason is the stator excitation,without excitation for asynchronous,should only produce relative movement,will have the effect of cutting magnetic induction line (or flux change),will produce electromagnetic electricalmotor1.blogspot.com induction force (i.e.,ampere force). And add the excitation,the stator can be seen as a magnet,has fixed the NS,with a rotating magnetic field synchronous rotation,so called synchronous motor. (magnets attract role) The classification of the generator can be summarized as follows:Motor {dc motor Alternator {synchronous generator Asynchronous generator (rarely used) Alternator is also can be divided into single-phase generator and three-phase generator.

The role of the condenser

Power system energy providers have the generator and condenser.Generator is to turn mechanical energy into electrical energy device,so the generator to ac synchronous motor the system which is available for the active power and reactive power.Condenser is a small amount of active power absorption system to supply the energy loss in the itself,to the system reactive power or absorb reactive power.Generator must have a prime mover drag,adjustable The camera don't need a prime

mover,but must be run in parallel with and power grid,and can't run alone.Condenser is made up of stator,rotor and excitation system.Because there are a large number of electromagnetic devices in the power system (refers to the inductive load,such as induction motor,electric welding machine,three phase generator induction furnace,etc.),In addition to consume a certain amount of active power,but also consume a certain amount of reactive power,and therefore need a certain amount of reactive power compensation

device - condenser (or capacitor).Along with the development of the power system constantly,reactive power increases,consequently generator to supply reactive power alone,will affect the generator active power output,it is not economic.At the same time in order to reduce loss of power line reciprocating transmission in various effectively improve system voltage level,improve the stability,improve the utilization rate of power generation equipment and reduce the power system The power losses,improve power factor,thus it is necessary to near the load center or set a certain capacity of reactive power equipment,to compensate for the lack of reactive power,improve electricity

electricalmotor1.blogspot.com The economic operation of power system.

Pipeline pump maintenance and repair

1,use after a period of time,found that the machine end face sealing leak,is caused by the machine sealing end surface wear,should adjust the ring,two screw loosening of the stainless steel screw,will ring forward appropriately,without Yin is preferred.wholesalemotor.blogspot.com 2,boot 8 to 16 hours a day for the best use of pump shall be equipped with spare parts with 24 hours of continuous use change regular maintenance,replacement period is generally two to three months,should be due for maintenance,does not affect production or continuous operation use may at any time for maintenance.3,pump maintenance methods: A. clean the pump casing and pump cover,impeller,both inside three phase asynchronous motor and outside www.facebook.com/guohong.trading dirt impurities,carefully check after washed clean,no damage may continue to use.B. removal and washing machine sealing combination of inside and outside dirt and impurities,check the motor lamination abrasion of the seals,wear or scratch the smaller usable fine metallographic sandpaper grinding on the tablet to level off after non-trace can continue to use,it can't take scar elimination must be replaced to grind.

Stepper motor frequency control of motor speed

Although the stepper motor with strong ability,high precision,rapid start-up speed the characteristics of easy to control,but in the actual operation process due to improper start and stop control,select the appropriate size three-phase asynchronous motor power still started shaking and stops the phenomenon of overshoot,from surface affect the control precision of the system.Especially the work in the frequent start and stop a step motor,this kind of phenomenon is more obvious [2].This paper proposes a kind of stepping motor based on single chip microcomputer control discrete acceleration and deceleration control method.Ordinate is frequency f,the unit for pulse/SEC or

step/SEC.Abscissa time t,www.dongfeng-

motor.comthe unit is in seconds.Stepper motor to f0 accelerate starts to run time t1 the highest frequency f,and then run at a constant speed,to t2 time began to slow,in t5 moment motor

stalling,the total number of N.The motor from static accelerated to the highest operating frequency

and the highest operating frequency to stop to the is the key to the stepper motor control,usually

adopt uniform acceleration and deceleration mode.

Deceleration control of stepping motor by single chip microcomputer,in fact is to change the output pulse interval,software and hardware can be used two ways.Software methods rely on delay program to change the frequency of the pulse output,ac synchronous motor of which the length of the delay is dynamic,and the method because of the need to constantly produce control pulse,occupies a large amount of CPU time; Hardware methods depend on single chip microcomputer internal timer to achieve,after each into the timer interrupt,change the time constant of timer (load),a two-dimensional table as a controlled object by stepping motor drives the ball screw in the

X/Y direction linkage.This paper discusses a kind of a circular trajectory with minimal parameters of interpolation method and the method of step motor frequency control of motor speed.Stepping motor control system of the development of the hardware and software collaborative simulation method was adopted,the system development cycle and cost can be centrifugal pump greatly reduced by acc when the pulse frequency

increases gradually,slows down the pulse frequency decreases.How to identify qualified factory motor? This method takes up less CPU time,it is a kind of high efficiency of stepping motor speed control method.Considering the single chip microcomputer resources (word length) and programming is convenient,the timer does not need to be calculated every step loading value.As shown in figure 3,using the discrete method to deceleration curve discretization.Rising speed is points after discretization steps,and every rise a step in the steps to keep for a period of time,to overcome the stepper motor rotor velocity lag caused by the moment of inertia.Only when the actual speed reaches preset to accelerating,actually also automatically correct local velocity error.

Delta connection of the motor and the difference between y connection

Under the small motor (4 kw) most using Y type connection,large motor usually adopt delta connection,star triangle decompression can also be used as electric motor cooling fan a large motor starting,when starting torque motor coil Y type runtime is only half of the delta connection,but the current is only starting about a third of the triangle. Triangle when starting current is rated current of 4 to 7 times,but the torque is big. Speed is the same,but different torque For ordinary three-phase electricity,the phase voltage 220 v,line voltage 380 v.Y connection is www.dongfeng-motor.com three-phase power to one end of each winding,the other end connect together. That each winding can gain phase voltage of 220 v.Delta connection is each winding end to end in order to form a triangle,three phase electricity in the Angle of the triangle. That each winding can gain line voltage of 380 v.If the phase voltage motor fan is 220 v,the rating of the motor is in y connection. If it is 380 v with delta connection.In particular,if the motor is belong to the rated voltage 380 v,you can use 220 v y connection step-down start,start to finish to switch to the delta connection

Triangle y connection to the motor's power

The stator winding y connection run by triangle instead, motor is long-term work under lower than the rated voltage of a special case. This way of running if used properly, to improve the power factor of the motor, managing electric energy has certain practical significance. A, triangular y connection to the motor's power Change the triangle to y connection, equivalent to the stator winding three phase voltage reduce to 1 /), then motor spare parts the motor of each quantity has the following changes: 1. The excitation power The field current reduced to about 1/2, so the excitation reactive power reduced to wholesalemotor.blogspot.com 1/3) (2) = 1/3.5. 2. The stator iron loss is directly proportional to the square of the voltage change, reduce to about a third. 3. The maximum torque and voltage changing proportion of square, reduce to a third. In order to maintain stable operation, the motor load will decrease accordingly. 4. Approximate slip and is inversely proportional to the square of the voltage change, under the same load, approximately increase to 3 times, but the speed changes. 5. Rotor current When the load is constant, the electromagnetic power constant; Due to the magnetic flux over voltage reduce to 1/3, square root 3 times, so the rotor current increase) increase winding fever. 6. Magnetic flux leakage reactive power Magnetic flux leakage voltage and reactive power to quadratic inverse proportion increase more, about three times as much. 7. The stator current of the stator current is determined by the rotor current and no-load current y connection, the former, the www.facebook.com/guohong.trading latter is reduced, so the stator current may increase or decrease, depends on the magnetic properties of the motor and load size. Fall, but in general, voltage, stator current increase. Active loss of 8. Due to the current in the rotor winding loss increase) and increased to 3 times, 3 times in the stator winding loss or increase or decrease, motor lamination depends on the change of the stator current. Comprehensive above, change the triangle to y connection, due to the reduced voltage, maximum torque decreases, and rotor current increase. If you maintain the load constant, is bound to cause the winding severe fever; Or because the torque is too small and make the motor stalling. In order to make the rotor after y connection instead Electric current shall not exceed the rating, should appropriate reduce the load of the motor.

6 kv motor insulation to reduce fault handling

Fault handling Although there are damage inspection found that bar insulation,but winding wire

itself is not affected.So we try to adopt a new method for processing,insulating layer with teflon

insulation bags,namely use insulation partition way on the electric motor cooling fan basis of the original winding wire rods to strengthen its insulation capability.Specific operation,the motor to overhaul,disintegration,and high pressure fan with bamboo knife of compressed air to motor winding and iron core of the dust cleared,the breakdown point and all loose clearance winding wire rods,with at least double (single withstand voltage 2000 v) teflon insulation tape winding,with bamboo slot wedge pressure,and then filled with resin,dry.All slot wedge update or upset,make the slot wedge,wire rods are stationary,able to withstand motor starting,running huge electric power.Processing has been completed,to direct current withstand voltage test of the motor again,when the step up to 5000 v,instrument and the "breakdown" signal,review found that motor used in 50 lead was copper core rubber line wholesalemotor.blogspot.com breakdown.Originally because motor operating environment temperature is higher,and the circulating water station in the original design,the motor selection using natural air cooling,according to the arrangement of design room,adjacent to the center line of the two motors from 3.0 m,running a motor cooling wind,is just another motor cooling air into the wind,because of the close,the motor often run in more than 40 degrees Celsius temperature environment,accelerate the rubber insulation aging,make

the rotor balancing machine shorten service life.The processing of wire insulation to strengthen on the motor.Lead to motor clean with gasoline,white cloth,and then using 6 kv with heat insulation tube heat insulation,all dc withstand voltage test was carried out on the motor after processed,the result completely conform to the requirements of the regulations.Equipment is working well so far.