Multimeter application tips measuring four

Measuring triode: usually we need R x 1 k Ω,whether NPN transistors or PNP transistors,whether it's in the small power,power,high power tube,measuring its be cb permanent magnet motor node should be presented with diode identical unidirectional conductivity,reverse resistance infinity,the forward resistance around 10 k.In order to further evaluate the pipe features of good or bad,if necessary,also many times should transform the ac induction motor resistance gear measurement,the method is: put R x 10 Ω file to the p-n junction is the resistance measurement are about 200 Ω; Set R x 1 Ω file to the p-n junction is the resistance measurement are about 30 Ω around (above table measured data of 47 type,other type table probably is a bit different,motor run capacitor can test a few more good tube to summarize,accomplish know fairly well) if big reading too much,can be concluded that the characteristics of the pipe is bad.

Still can put table at R x 10 k Ω measured again,the low pressure pipe (triode pressure are basically in more than 30 v),the cb junction reverse resistance should be in the up,but its be junction reverse resistance may have some,the clock will be a slight deflection (generally will not exceed one-third of full scale,varies according to the pressure of the pipe).Similarly,at R x 10 k Ω profile measurement of NPN transistors () or between ec ce (to PNP transistors) resistance,between the clock may be little deflection,but that doesn't mean the pipe is wholesalemotor.blogspot.com bad.But with R x 1 k Ω gear measurement under ce or resistance between ec,header instructions should be infinity,or pipes is a problem.More than that to clear the measurement for silicon tube,the germanium tube shall not apply.But now germanium tube is also very rare.In addition,calls a "reverse" is for p-n junction,direction of NPN and PNP tubes is actually different.

The working principle of the single-phase ac motor

Only a single phase ac motor winding, is squirrel cage rotor. When a single-phase sinusoidal current in the stator winding, the motor can produce an alternating magnetic field, the magnetic field strength and direction interplanting sine law of change at any time, but is fixed on the spatial orientation, say again so the magnetic field is alternation pulse magnetic field. This alternation pulse magnetic field can be decomposed into two at the same speed and direction of rotation are instead of a rotating magnetic field, when the rotor static, the two rotating magnetic field generated in the rotor torque of two equal and opposite, making synthetic torque electric motor 12v 500w is zero, so the motor can't rotate. When we use the motor rotates in the direction of a force (clockwise), then the rotation of the generator stator rotor and clockwise direction magnetic field between the cutting lines of magnetic force movement decreases; The rotation of the rotor and counterclockwise direction magnetic field cutting lines of magnetic force between the movement. 

This balance is broken, the total electromagnetic torque generated by the rotor will no longer be wholesalemotor.blogspot.com zero, rotor spun along the driving direction. To make single-phase electric function automatically spin, we can add a starter in the stator winding, starting with the main windings in space by 90 degrees, starting winding to concatenate a suitable capacitance, makes differ with approximation in the phase of the primary winding current 90 degrees, the so-called split-phase principle. These two differ 90 degrees of electricity flow in time into the two differ 90 degrees of winding on the space, will be produced in the space (two-phase) rotating magnetic field, under the effect of the rotating magnetic field, the low rpm alternator rotor can be automatic starting, after starting, to speed up to a certain, with the aid of an installed on the rotor of the centrifugal switch or other automatic control device will start winding broken, only main winding work in normal working conditions. Therefore, starting winding can make short work. But there are a lot of time, starting winding is not broken, we call this kind of motor capacitor, single-phase motor to change this kind of motor, can be achieved by changing the position of the capacitor is concatenated.

Motor are briefly introduced

Motor is a kind of rotary electric machine, motor. Motor electrical energy into mechanical

www.facebook.com/guohong.trading energy, it mainly includes a magnetic field to produce electromagnetic winding or the distribution of the stator winding and a rotating armature or rotor. Under the effect of rotating magnetic field of stator winding, the effective of the electric motor stator winding is energized and make its rotation by the role of the magnetic field. According to the reversible motor principle, if the motor without any change in its structure, motor or motor use, also can be used for the generator. 

It is the electrical asynchronous motor energy into mechanical energy of a machine. Usually work part of

the motor rotation, called the motor rotor motor; Also has a linear movement, known as linear motor.

Electric function provides a large range of power, class from milliwatts to kw. Machine tools, water pumps, motor drive; Electric locomotive, elevators, traction motor is electric motors pricerequired. Family life of the electric fan, refrigerator, washing machine, and even all kinds of motor toys is inseparable from the motor. Motor has been used in all aspects of modern social life.