Current transformer

Cast Iron electrical motor auto spare parts 
Specifications
1. 20 years manufacturing experience 
2. competitive price,high quality

3. Delivery Detail:within 10 days after receiving deposit 
Micro current transformer is similar to the transformer is also according single phase motor to the principle of electromagnetic induction to work, is the voltage and the micro current transformer of transformer transformation transform is current. As shown in figure measured current winding N1, called the primary winding (or the original winding, primary winding); Winding N2 measuring instrument, electric motor price known as the secondary winding (or) vice winding and secondary windings. Micro current transformer primary winding current I1 and I2 secondary winding current ratio, than the actual current K. Micro current transformer in the motor electric rated electric current work shed than called current transformer rated current ratio, expressed in Kn. Micro current transformer can be roughly divided into two classes, measuring current transformer and protection current transformer.

Direct torque control

 Direct Torque Control (Direct Torque Control, DTC), the text of the abroad some also called Direct self - Control, DSC, literal translation for Direct self Control, the concept of Direct self Control for Torque as the center for www.dongfeng- motor.com integrated Control, not only to Control the Torque, also used for the amount of flux linkage Control and flux linkage Control. The difference between the direct torque control and vector control is that it is not by controlling current, flux amount of indirect spare parts torque control, but the torque directly accused of quantity control, as the essence of which is using space vector analysis method, with the stator magnetic field orientation, the motor electric stator flux and electromagnetic torque in direct control. In 1985 Germany's ruhr university DiPu brock (m. epenbrock) professor is presented based on the first hexagon and round flux trajectory of the Direct torque control theory, he is called Direct self - control - DSC. This method does not need complex coordinate transformation, but directly on the motor fan cover stator coordinate computing the size of the torque and flux of the mold, and by direct tracking of flux and torque PWM pulse width modulation and high dynamic performance of the system.

3 okw motor, 380 v voltage. The power factor is 0.2, could you tell me how to calculate the rated current?

 Rated current I = P30KW U0.38 KV / 1.732 * * 0.2 = 227.9081 A, but electric motor 12v 500w 30 kw motor power factor can't be so low ah, do you want to calculate no-load running current of motor. The question you ask is problematic. ac three phase motor 30 kw motor power factor should be above 0.75. If according to the capacity of current rating: I = P30KW U0.38 KV / 1.732 * * 0.75 = 60.7755 A. Teach you two formula, very useful: "capacity divided by the number of kv, dealer by coefficient of seventh. "A kw, two current" can estimate the rated current of three-phase motor. Low power factor, then the acmotor2.blogspot.com motor should be banned the example of the net. Line current of three-phase ac asynchronous motor I material 2 P, P - power, kw. I material 2 x 60 kw motor current 30 = 60 a.

What are the components of transformer overhaul?

(1),hanging out of the body,overhaul,body (core,coil,generator generator set tap- changer and lead);(2),maintenance safety cover,oil storage tank,gas,heat pipe throttle single phase generator and casing;(3),and cooling device and oil filter equipment,(4),filter oil or oil changes,if necessary,dry processing.(5),the access control and measuring instrument,signal and protection device;6,clean up the shell,if necessary,paint;All landowners,assembly and measurement and test.(1),hanging out of the body,overhaul,body (core,coil,tap-changer and lead);12v mini generator motor (2),maintenance safety cover,oil storage tank,gas,heat pipe throttle and casing;(3),and cooling device and oil filter equipment,(4),filter oil or oil changes,if necessary,dry processing.(5),the access control and measuring instrument,signal and protection device;6,clean up the shell,if necessary,paint;All landowners,assembly and measurement and test. Advantages of wound asynchronous motor can be through the collector ring wholesalemotor.blogspot.com and brush,plus resistor in series with the rotor loop,to improve the starting performance and can adjust speed change and resistance within a certain range.But the wound,more complicated than the squirrel- cage asynchronous motor structure,poor reliability of the movement of the price is more expensive.

The selection of ac contactor and operation maintenance

(1) to electrical motor choose:(1) rated current of the primary loop contacts should be greater than or equal to the rated current,accused of equipment control motor contactor should also be considered the starting current of the motor.In order to prevent frequent operation of contactor main contact ablation,frequent movement of contactor rated current can reduce use.(2) the electromagnetic contactor coil rated voltage is 36 v,110 v,220 v,380 v,the electromagnetic coil allows within the scope of 80%~105% of rated voltage.(2) operation maintenance:(1) check in the operation of the project:1) by the load current is within the contactor ratings;2) contact points and the signal is consistent with the circuit state;3) running sound acmotortrading.blogspot.com is normal,have because poor contact and heat discharge;4) with or without electromagnetic coil overheating electromagnet short-circuit rings with and without exception.5) arcing cover any loose and damage;6) auxiliary contact with and without damage;7) transmission part with and without damage;8) have running environment without adverse factors of running around,such as too much vibration is too large,poor ventilation,dust,etc.

(2) maintenance:in electrical equipment maintenance work,to maintain the contactor shall work.1) external maintenance:a.external dust cleaning;B.check all fasteners are loose,especially the conductor connection parts,prevent loose contact and fever;2) contact system maintenance:a.check of dynamic and static contact position is,whether the three-phase closed at the same time,the contact spring should be adjusted if you have any questions;B.check contact wear,wear depth shall not be more than 1 mm,contact burning,welding off,must be change in time;When slight loss,generally does not affect the use.Clean the contact is not allowed to use sand paper,should use the plastic file;C.and measuring insulation resistance,electrical motor resistance of not less than 10 m Ω;D.check whether the auxiliary contact action is flexible,contact schedule should comply with the specified value,check whether there is any loose fall off on contact,found the problem,should be timely repair or replacement.3) maintain core parts:a.cleaning the dust,especially the moving parts,and between the core and interface;B.check the fastening situation of iron core,iron core run loose cause noise increase;C.core end ring have fall off or break to repair in time.4) electromagnetic coil maintenance:a.measuring coil insulation resistance;B.the coil insulation discoloration,aging,coil surface temperature should not exceed 65 ° C;C.check the coil wire small electric motors connection,if there are any open welding,burning loss should be timely repair.5) arcing cover parts maintenance:a.check whether the arcing cover is damaged;B.arcing cover any loose and location changes;C.remove arcing cover gap within the metal particles and sundry.


(3) working principle of the vacuum contactor,vacuum contactor with vacuum arcing medium,its main contact seal in a special vacuum arcing tube.When operating coil electricity,armature,absorption in the contact spring and vacuum tube autistic force under the action of contact closure;Operating power coil,the armature reaction spring overcome vacuum tube autistic force release,off contact.Contactor breaking current,the contact gap formed by metal vapor can be formed in the platinum scale,affect the service life of the contactor.

The generation of arc

When using switch electrical disconnect current,if the circuit voltage not less than 10-20 v,current not less than 80~100 ma,electrical contact between will produce electric arc.Arc is free gas of high temperature and high electrical conductivity,it not only has a lot of damage to contact,and prolongs the time that disconnect circuit.Therefore,in the structure and working condition of the switch

electric acmotortrading.blogspot.com before,first to

see how its produce and put out.The formation of the arc is contact between neutral protons

(molecules and atoms) is the process of free.Switch contact separation,the distance between the

contact is small,high electric field intensity E (E = U/d).When the electric field intensity exceeds

3 x 1000000 v/m,the electrons on the surface of the cathode electric field force will be pulled out

of the free electrons to form a contact space.

This free way is called:strong field emission.The free electrons emitted from the brake

rotorcathode surface and the contact between the original a few electronic,in under the

action of electric field force to accelerate the anode movement,constantly and neutral particles collide on the magnetic motor way.As long as the electronic velocity v is

high enough,the kinetic energy of the E = mv2 is enough big,can from the nature of playing

electronic,the formation of free electrons and positive ions.This phenomenon is called collision

free.New form of free electrons also accelerated motion to the anode,similarly will free with neutral particle collisions.Collision ionization is continuously as a result of the contact between full of electrons and positive ions,greatly conductance; Under the applied voltage,arc medium is punctured,the circuit again by conduction.

Contact arc burning gap between called arc gap.Arc,arc gap between the heat on the surface of the cathode of the electrons gain enough energy and emission,outward form thermoelectricity field emission.At the same time under the action of high

temperature (arc center part to electric motors

pricemaintain the temperature can reach more than 10000 ℃),irregular hot gas neutral

particle movement speed increase.When have enough kinetic energy neutral particles collide with each other,will be free and form electrons and positive ions,this phenomenon is called thermal dissociation.Increase with the distance separate contact,the contact between the electric field intensity E gradually decreases,and the arc combustion is mainly rely on thermal free

maintain.Between switch electric contact,free process at the same time,also happening to the

disappearance of a charged particle free process.

Cooling way

1)cooling:motor in the energy conversion,there is centrifugal pump always a small part of the loss into heat,it must be through the motor shell and the surrounding medium heat out ceaselessly,This process of send out quantity of heat,we are called to cool.2)the cooling medium,heat transfer of gas or liquid medium.3):primary cooling medium temperature is lower than the portion of the motor parts of gas or liquid medium,it contact with the part of the motor,and gives off heat away.:4)secondary cooling medium temperature is lower than the primary cooling medium of gas or liquid medium,through the outer surface of the motor wholesalemotor.blogspot.com or the cooler will be released by the primary coolant heat away.5)final cooling medium:heat transfer at the end of the cooling medium.6)around the cooling medium: motor surrounding gas or liquid medium.Medium:7)far a away from the motor of the motor fan media,through the inlet and outlet pipe or channel heat and drain suction motor cooling medium to the distance.8)cooler:make a cooling medium heat transfer to another kind of cooling medium,and keep the two separate device cooling medium.