The difference between the speed reducer and frequency converter speed control Electrical engineers

Through the difference between the speed reducer and frequency converter speed control of mechanical devices often need to adjust the speed of three-phase asynchronous motor,often use reducer adjustment change frequency reduction ratio or transducer to adjust the speed of the motor. But by what is the difference between the speed reducer and frequency converter speed control? Together (see electrical engineer) to take us to get to know it.Reducer speed:Reducer is through mechanical transmission device to reduce the motor (motor) speed,such as common gear deceleration,turbine worm reducer,etc.Through the reducer to adjust the speed of the motor general need to make sure the following information:1,the types and specifications of the motor,speed,power (or torque),starting characteristics,short-term overload capacity,the moment of inertia,etc.

2,the types of mechanical work,specifications,purpose,rotational speed and power (or torque). Working system: constant load or changing load,variable load load diagram; Rev.,braking and short-time overload torque,start frequency; Shock and vibration levels; Direction of rotation,motor and reducer coupling way,whether the shaft extension with radial force and axial force.3,installation type (reducer and motor,the relative position of working machine,vertical and horizontal).4,transmission ratio and the margin of error.5,environmental temperature,air velocity,dust concentration and environmental conditions such as ph value; (if there is a circulating lubrication and cooling conditions,lubrication station) and the limitation on the vibration and noise.6,to the degree of service life,Motor vehicle safety and reliability requirements.7,the requirement for the size and weight.8,the demands induction motor price of operation and control.9,the source of material,blank,standard parts and inventory.10,on volume,cost and price requirements.

11 and delivery term.Frequency converter speed control:Inverter is by changing the frequency of alternating current motor (motor) in order to achieve the purpose of speed regulation. Reduce the motor speed by the frequency converter,you can achieve the goal of energy saving. But generally within 0-50 hz frequency conversion motor to realize the constant torque speed control,within the scope of 50-100 hz to realize constant power speed regulation,and stepless speed regulation,wide speed range.To sum up,through the difference between the speed reducer and frequency converter speed control is mainly: reducer speed a wider range of speed (slow),but generally not stepless speed regulation,speed regulating motor after a lot of physical and electrical parameters can be continued,in addition to the speed loss; And use frequency converter speed control can realize stepless speed regulation,but limited range of speed (only within 3 -- 100 hz speed),speed when affected by a lot of electric parameters,and can't guarantee the original motor of the number of parameters,and fever more serious.

Currently there are 5 kinds of electric vehicles

brush series brushless dc motor,permanent magnet dc motor,ac motor (induction motor),permanent magnet synchronous motor and BLDC motor FM.Brushless dc series motor are: the advantage is that big start torque,overload capacity is strong,the disadvantage is that need to change the carbon brush,high speed has the ring of fire,not suitable for high speed running,low efficiency,large volume,protection and energy feedback is poor,mainly used in electric tricycle.Brush with permanent magnet dc motor: advantage is better than brushless diesel generator dc series motor has high efficiency,energy feedback is good,starting torque and overload ability general,defect is need to change the carbon brush,high speed has the ring of fire,not suitable for high speed operation,efficiency,large volume,moderate protective ability is poor,mainly used in electric tricycle.

Ac motor,the advantage is simple structure,high reliability of motor itself,the disadvantage is that starting torque is small,large starting current,motor depends on increasing the starting current to produce a large torque,but due to the battery characteristics,the battery provides large current,affects the motor torque,the motor efficiency is low,the control of complex,energy feedback performance is poor.Switched reluctance motor: advantage is in low speed with large torque,defect is low speed vibration,noise,low efficiency,poor energy feedback,rarely used.Permanent magnet synchronous motor,the advantage is with high efficiency,energy feedback acmotortrading.blogspot.com is good,the disadvantage is that when the low speed torque cannot ascend,lose the step problem,rarely used.

Brushless dc motor: advantages are: (1) motor external characteristic is good,very accord with the load characteristics of electric vehicles especially motor has low speed high torque characteristics of the precious,can provide large starting torque,satisfy the requirement of the vehicle acceleration.(2) the wide speed range,the motor can run tall in the low speed range,due to mechanical commutator and brush motor,the motor can run under low.(3) motor with high efficiency,especially under the light load cars,motor can still keep high efficiency,it is very important for precious battery power.(4) overload capacity is strong,this kind of motor than Y series motor overload capacity can be improved more than 2 times,can meet the needs of the vehicle bumps blocked.(5) regenerative braking effect is single phase generator good,because of the permanent IE2/IE3 electric motor magnetic motor rotor has the very high,when the car downhill or brake motor generator can be completely into the state,to recharge the battery,the electric braking effect at the same time,reduce the financial burden on mechanical brake.

6.Motor small volume,light weight,high power,can effectively reduce weight,save a space.7 no mechanical commutator motor,USES the totally enclosed structure,prevent dust from entering the motor internal,high reliability.Simple than asynchronous motor was motor control system.Faults is more complicated than the ac motor motor itself,brushless dc motor controller than there are complex.

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.

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.