显示标签为“water pump motor”的博文。显示所有博文
显示标签为“water pump motor”的博文。显示所有博文

2014年8月12日星期二

Single polarity can drive with dual polarity the gm?


Single polarity cannot be used instead of bipolar drive,drive and bipolar drive can be used instead
of a single polarity drives.Because of the two kinds of drive current distribution in different
ways,the effect of Y series three-phase asynchronous motor is different also.Single polarity drive (for example: HSM8672),with one polarity connection is dedicated to four phase stepper motor.For example,there are five lines,six lines,eight line lead electric motor cooling fan ways four phase stepper motor,can use
either single polarity drives,and to be able to use bipolar drive (for example: HSM1524-8).However,to achieve the best efficiency,or targeted to select the drive as well.Segmentation principle of stepping motor drive is what?If using subdivision driver,under the conditions of 10 subdivision drive the motor,step motor each run A micro,current changes in the winding is only 0.3 A,rather than 3 A,and the law of electric current is A sine curve changes,thus greatly improve the motor vibration and noise,therefore,on the performance of advantages is the real advantages of segmentation.Because subdivision driver to precisely control the motor phase current,so the driver electric motor cooling fan should have quite high technical requirements and technical requirements,the cost will also be higher.Note that there are some domestic drive "smooth" is used to replace the subdivision,sometimes also called segmentation,but it is not really a subdivision,hope the broad masses of users must distinguish the nature of the different:1."smooth" is not precise control of the motor phase current,but the rate of change of the current slow some,so "flat" do not produce micro step,and subdivision microstep can be used for accurate positioning.

After 2.The motor phase current is smooth,can cause the drop of the motor torque control and not only do not cause the decline of motor torque,on the contrary,the torque will be increased.For automated motion control system of step motor,there are mainly two phase,three-phase,four,five phase hybrid stepping motors.Must match the corresponding stepper motor drives,to be able to accept the controller (CPU,PLC,etc.) the digital signal.In order to reduce the
stepper motor work noise,usually using subdivision driver,especially at low speed working electricalmotor1.blogspot.com condition is
more noticeable.Many people know about "segmentation" is not special,just think,segmentation is in
order to improve the precision degree,actually otherwise,segmentation is mainly to improve the
performance of the three-phase asynchronous motor,now shows as follows: stepping motor subdivision
control is precisely controlled by the driver of stepping motor phase current,the two-phase motor,for
example,if the rated current of motor is 3 a,if you are using a conventional drive (such as a common
mode of constant current chopper) driving the motor,every step motor running,in its winding current
will mutations from 0 to 3 a or 3 a mutation to 0,the great changes in phase current,is bound to
cause vibration and noise of motor running.

2014年7月22日星期二

The rise of temperature of the motor and its related knowledge in electrical engineer to study

A summary of motor temperature rise and the temperature rise of the knowledge: Temperature rise is the motor and the environment temperature difference is caused by the electric heating. Run the motor iron core in alternating magnetic field can produce iron loss, winding can produce copper loss, after the power supply and other stray loss, etc. These will make the motor temperature perkins diesel generator rise. On the other hand motor will also heat dissipation. When heating and cooling is equal to equilibrium state, temperature no longer rises and stable on a level. When fever increase or reduce the heat will destroy the balance, make temperature continues to rise, enlarge the temperature, increased heat dissipation, at a higher temperature reaches a new equilibrium. But when the temperature difference of the temperature rise www.facebook.com/dongfeng.motor has increased than before, so that temperature is an important index in motor design and operation, marked the fever of the motor, in operation, such as the motor temperature rise suddenly increases, motor has a fault, or duct obstruction or load is too heavy. Factors such as temperature and temperature relationships: For the normal operation of the motor, in theory, under the rated load its temperature rise should have nothing to do with environment temperature, but the fact is still affected by the factors such as environmental temperature. When the temperature drops, the normal motor temperature rise will decrease slightly. 

This is because the winding resistance R, copper consumption reduced. Each drop 1 ℃, R down about 0.4%. To the cold machine, the ambient temperature increase 10 ℃, the ac synchronous motor temperature increased by 1.5 ~ 3 ℃. This is because the winding copper loss increases with temperature rise. So the temperature change of large influence on motor and closed. Every high air humidity 10%, due to the improvement of thermal conductivity, temperature rise can be reduced by 0.07 ~ 0.38 ℃, an average of 0.19 ℃. Elevation in 1 000 m for the standard, every litres of 100 m, the temperature rise of the temperature increase limit value of 1%. The maximum permissible limit working temperature and working temperature: Usually say that the class A limit working temperature is 105 ℃, A level of the highest working temperature is 90 ℃. So, limit working temperature and the maximum allowable working temperature difference? In fact, it is associated with measuring method, different measuring methods, it reflects the values, the meaning is different also. The thermometer method The measurement results reflect the local surface temperature of the winding insulation. This number, on average, than the actual maximum temperature winding insulation lower "the hot spot" of about 15 ℃. The most simple, the most widely used at the scene of the medium and small motor. Resistance method The measurement results reflect the average temperature of the winding wires. The number than the actual maximum temperature according to different insulation level lower 5 ~ 15 ℃. The method is to measure the conductor of the cold and hot resistance, according to the formula to calculate the average temperature rise. Embedment will copper or platinum resistance thermometer thermometer trial or thermocouples embedded in the winding and iron core or other need to measure the expected high temperature parts. The measurement results reflect the temperature of the temperature measuring element contact point. Large motor is often adopted to monitor the operating temperature of the machine. (see electrical engineer) measurement methods to measure the temperature and the actual maximum temperature have certain difference, so the insulation must be "limit working temperature minus the difference between" is "the highest working temperature".