Measurement techniques for five multimeter application skills

 Now most common triode is powder coating,how to accurately judge the triode three pin which is b,c,e? Triode b very easily measured,but how to judge which is c which is e? Here recommends three methods: the first method: for measuring triode hFE jack pointer table,first measure b pole,throw triode plug into motor vehicle spare parts the socket (b,of course,is very can plug accurate),measure hFE value,then the measuring tube upside down again,the measured values of hFE larger one,each pin insertion position is correct.The second method: to measure without hFE jack table,or is not convenient to insert the socket pipe is too big,can use this method: of NPN transistors,first measure b (the pipe is NPN and PNP b and its feet are easy to measure,isn't it?) ,put table in R x 1 k Ω gear,to connect the red pens and hypothetical e very (note that take the hand don't run into table of red pens and pen or pin),the fan motor black pens and answer the hypothetical c,at the same time hold the table with his fingers tip and the pin,will pick up the pipe,with the tip of your tongue lick a b,the header pointer should have a certain amount of deflection,if all the pens and you answer correctly,the pointer will be bigger,if wrong,the pointer will be smaller,the difference is obvious.

Which can determine pipe c and e.For PNP transistors to black pens and answer the hypothetical e very (hand don't touch the tip or pin),red pens and answer the hypothetical c,at the same time hold the table with his fingers tip and the pin,and then use the tip of the tongue lick a b,if the pens and correctly,header pointer will deflection is larger.Of course when measuring the pens and to discuss the test twice,comparative reading before final decision.This method applies to all appearance triode,convenient and practical.According to the clock deflection amplitude,but also can estimate the pipe amplification ability,of course it is by experience.The third method: first to determine the pipe after the NPN and PNP type a and b,put table at R x 10 k Ω,of NPN transistors,the black pens and connect e,red pens and pick up c extremely,the clock may have some deflection,the PNP transistors,electricalmotor1.blogspot.com black pens and c extremely,red pens and pick up e very,whose hands may have a certain amount of deflection,which in turn would have deflection.This can also determine triode c and e.But for the high pressure pipe,this method is not applicable.

Research on the positioning control of asynchronous motor - brake physical process

 Stator winding from three-phase power disconnected,bubbled into direct current,the stator magnetic field from the rotating state into a fixed position,same size constant magnetic field,because of diesel generating the influence of the mechanical inertia,rotor is rotating in a clockwise direction,the rotor conductor cutting constant magnetic field.Due to the cutting direction,asynchronous motor in contrast to the state of electric,so the rotor induction electric potential and the direction of the induced current,also in contrast to the state of electric,cause the torque of the motor reverse,counterclockwise.M torque and rotational speed n direction on the contrary,as the braking state,the asynchronous motor's kinetic energy into electrical energy,consumption on the motor rotor resistance of the circuit,so that braking energy.

The torque of the motor and load torque,under the electrical motor joint action of slow down soon.When rotation speed is equal to zero,the rotor conductors are no longer cutting magnetic field,rotor induction electric potential and induced current reduce to zero,the motor is no longer produce electromagnetic torque,which can control the production of mechanical parking.Analysis was conducted based on Xm = constant conditions.In the process of braking energy excitation reactance Xm is not constant.But due to the change of Xm for motor operation effect is not big,so think Xm is constant in the theoretical analysis.Using energy consumption braking,both must have bigger brake torque,and acmotortrading.blogspot.com don't make,rotor loop current is too large,the connection mode is shown in figure 3,determine the following relation can be used asynchronous motor stator dc excitation current I_ and rotor circuit of series resistance R Ω.

Family circuit design

2000 years ago,the circuit design is commonly:into the line 4-6 was,1.5 was lighting,socket was 2.5,air conditioning was 4 line.2000 years later,the circuit design is single phase ac motor commonly:into the line 6-10 was,2.5 was lighting,socket was 4,air conditioning was dedicated line 6.Air switch,also called

automatic www.facebook.com/dongfeng.motor switch,low voltage circuit breaker.Working principle is:when the current exceeds the rated current,short circuit,loss of pressure,and so on and so forth,to cut off the circuit automatically.At present,the main switch common with knife switch with porcelain insurance already was washed out () or single phase electric motor the air switch (with small leakage protection circuit breaker).Now family use DZ series air magnetic generator switch,common have the following model/specification:C16,C25,C32,C40,C60,C80,alkane,C120,such as specifications,including C said tripping current,namely the takeoff current,C32 takeoff current 32 security,for example,general installation 6500 w heater with a C32,installation of 7500 w,8500 w with C40 open water heater.