The working principle of the pump and fan - screw pump

Screw pump is a kind of using screw pitch rotary pump suction and discharge the electric vehicle motor liquid. Screw pump rotor by active screw l (can be a root, also can have two or three) and driven screw ac electric motor 2. Driving screw and driven screw do turn in the opposite direction, thread pitch, fluid from inlet to be screw axis forward pressurization to discharge. This pump is applicable to high acmotortrading.blogspot.com pressure, small flow. Refrigeration system normally used for transport and the speed of oil pump bearing grease.

Current transformer selection and calibration accuracy

Accuracy refers to within the scope of the provisions of the secondary load, a current of the maximum error when rating. China's current transformer accuracy and error limits as shown in table 1, for different measuring instrument, should choose different accuracy of current transformer. The choosing principle of accuracy: billing measurement with the current transformer is the accuracy of 0.2 ~ 0.5; Used to monitor the size of the load current in outlet and inlet line of each loop current meter should choose 1.0 3.0 level current transformer. In order to guarantee the accuracy of error is less than specified value, generally also check current transformer secondary load (ei), transformer secondary load S2n S2 is not greater than the rated load, the selected accuracy can be guaranteed. The accuracy of calibration formula: S2 S2n or less. Secondary loop load l: www.dongfeng-motor.com depends on the value of the secondary loop impedance Z2 is: S2 electric motor 12v 500w = I2n2 ︱ Z2 ︱ material I2n2 (∑ ︱ Zi ︱ + + RXC RWl) or S2V1 material ∑ Si + I2n2 (RWl + RXC), Si, Zi as the secondary circuits of the instrument, the rated load and impedance of the relay coil RXC for all joints in the secondary loop, contact contact resistance, generally take 0.1 Ω, RWl for the secondary loop wire resistance, calculation formula is: the RWl = LC/(r (S). Type, r for the conductivity of the wire, copper wire 53 m/r = (Ω was), aluminium wire r = 32 m (Ω was), S for cross-sectional area (was), LC for the calculation of the wire length (m). A multitude of transformer to instrument one-way length of L1, is: L1 transformer is star. LC = L1 two-phase V wiring. 2 a phase l1 type connection. The accuracy of current transformer used for the relay protection has 5 p and l0P. Protection level of accuracy is based on accurate rating limit down an electric epsilon % of the maximum error of the composite to nominal (such as 5 p corresponding epsilon % = 5%). So-called rated accurate limit a rated current is a current Induction motor is a current multiples (n = I1 small three phase motor / I1n), also known as rated limit coefficient accurately. Is asked to protect by current transformer in the range of possible, its biggest composite error is less than epsilon % value.

Single-phase transformer economical one

motor Lamination ac motor blender parts 

Specifications
1. Lamination of electric motor 
2. IP54 class F 
3. 100% copper 
4. silicon steel stamping 

5.stunning performance
Cost of small capacity transformer single-phase power supply system construction, light load area can reduce construction investment. Big load region of single-phase power supply acmotor2.blogspot.com system renovation, must have a larger economic investment. I see, some pilot single-phase transformer in residential quarters, is a large transformer into multiple small transformer, near load installation, shorten the distance, a low pressure trunk, due to the distance of the source to auto parts the load is certain, shortening the distance between motor parts low voltage power supply, is bound to extend the transmission distance, this transformation requires a lot of investment, such as electric motor 12v 500w the original 3 unit 30 families use 160 kVA three-phase transformer.

 high efficiency high power electric motor Y2 motor
Specifications
1. effiency: IE2 and IE1 
2. 20 years manufacturing experience 
3. 12 months guarantee 
4. low noise and vibtration
switch to three single-phase 50 kVA transformer power supply, table 2 lists two retrofit scheme of materials and the change of loss, obviously increased the construction investment. First, in order to reduce the low voltage main line loss, to introduce the high voltage line load center, increase the high voltage line construction investment. Secondly, using many sets of small capacity transformer no-load loss and load loss, after all is more than the original list of large transformer. Third, the purchase funds are many sets of small capacity transformer is greater than the single purchase money of big capacity transformer. As residential electricity more abroad, several or each use of a single-phase transformer, because countries rich, large amounts of money into the electric power department. Although the investment is bigger, for their overall economical.

New type of automobile permanent magnet generator and its application prospect

New type of automobile permanent magnet generator and its application prospect The new permanent magnet generator,automotive development and application At present,the main motor generator is silicon rectifying generator.The main defects such as: magnetic field generated by the electric field winding,rotor field winding burned,break easily,electric consumption,and must be provided by the battery field current to power generation,this is bound to increase the car cost.Silicon rectifying generator with a carbon brush slip ring structure,the slip ring diameter is large,high linear velocity,carbon brush is easy to wear and short service life,high failure rate.The other is a brushless generator,it increases the air gap magnetic field,the magnetic flux leakage,low material utilization,cost is high.Domestic automobile generator is mainly ferrite permanent magnet alternator,power under 200 w,not directly to automotive wiper,heater,electric horn,such as dc power supply,also can't give battery charging.At home and abroad in recent years,with a new generation of rare earth NdFeB permanent magnet materials,transforming traditional claw auto alternator,with high precision control and regulating circuit,the advanced technology of permanent magnet motor generator system.Such as JFYW series vehicle permanent magnet alternator,USES the ndfeb permanent magnet,compared with the line around the excitation generator,not made of black metal casting (forging) claw pole and the yoke,without excitation coil,without brush and collector ring.

Has the features of simple structure,reliable operation,long service life,small volume,light weight,less loss,high efficiency,low cost,and improve the vehicle electrical properties etc,and does not produce interference of on-board electrical appliances,reduce the battery charge and discharge frequency,director of the service life of the battery,the battery completely without electricity or out of the special circumstances of the battery,starter drive car.Since this series generator with low forward unique design,therefore,by the majority of urban transit system and low speed slow for a long time,frequent starting stop users widely recognized and applied. Second,the structure of the permanent magnet generator Automobile permanent magnet generator including casing,rotor,stator and other components.Fixed on the outside of the rotor steel shaft with weak magnetic circle,weak permeability round set has a groove,groove on with permeability and strong permanent magnet blocks,permeability and strong permanent magnet blocks of ratio of 2:1,the number of two pieces of permeability blocks and the clamp in the middle of the a strong permanent magnet blocks,a pair of poles with weak magnetic material between two pairs of magnetic poles apart,each pole of the adjacent opposite polarity.

The generator is suitable for automobile,engineering machinery,such as motor vehicles and stationary power plant as the charging power supply of the power supply.It consists of the excitation of the three-phase permanent magnet synchronous generators,after rectification,the output and parallel to the car battery power supply,electrical equipment at the same time can also to the battery.The generator in the development of not only successfully solves the permanent magnet generator under variable speed and variable load conditions of voltage stability problem,and solved the permanent magnet generator short circuit,fault protection,has high precision,high efficiency,low pressure charging performance is good,the advantages of larger than power,has a broad application prospect.Promote the use of automobile permanent magnet generator,can save a lot of energy,prolong the service life of battery,improve the economic efficiency of operations,but also conducive to the development and utilization of the rare earth resources of our country. Three,the permanent magnet generator technical advantages of the system Magneto's advantage is that it can be in 0 ~ 15000 RPM and high temperature environment to work properly,its motor parts advantages are: (1) no battery power.Because of its rotor is a permanent magnet,without excitation current,as long as the engine driven rotation can generate electricity,save energy,compared with the same volume of excitation generator,can get double the same circumstances,the output power,and when the damage to the vehicle battery power supply system in travel can still work normally,even without the battery,as long as the rocking forward motivation or slide ignition operation can be realized. 

(2) the power supply at low speed performance is good,small voltage regulation.When the power is low,the electromagnetic parameters of the same case,silicon rectifying generator zero current,permanent magnet generator can be exported 3 a ~ 5 a "field current",greatly improve the power water pump performance at low speed.As small leakage,direct axis and quadrature axis armature reaction reactance is small,the armature reaction is weak,so the voltage regulation is small,its external characteristic is relatively flat,high power,output voltage stability is also very good. (3) simple structure,reliable operation,stable performance.Only on the rotor structure of permanent magnet generator shaft,claw pole,wafer type ndfeb,simplify the processing procedure.A 25% reduction in weight compared with the same power generator,prolong the service life of the bearing,and effectively reduce the brush and slip ring friction of radio interference.Permanent magnet generator avoids electrical excitation generator excitation winding is easy to burn,bolt and the problem of carbon brush and slip ring is easy to wear.Electronic regulator and generator etc,make the generator overall realize dc output,small volume,light weight,easy to maintain.The attention of the auto industry.

The dc grounding method 3

Hybrid grounding: so-called hybrid grounding is within a device of the circuit board in the shortest wire connected to the chassis,or signal circuit is the base of the related equipment,in the shortest wire grounding connected to the same metal body,and then multiple devices with wire received a fixed in the same spot.Like this grounding method called hybrid grounding.Hybrid grounding in engineering is the most simple way,is in the ac power into house master switch,the zero line repeat grounding (or zero line connects to housing on the structure of the main generator stator steel bar),and then in the power of the zero line leads to a PE line should wholesalemotor.blogspot.com connect all grounding point.Second,ring grounding network for earth,is the grounding body into a closed loop around the building.

Within such ground network to make the interface of the electric field electric motors price distribution is evener,step to reduce the harm to people,and also reduce indoor when affected by lightning,and because of the large ground potential gradient to counter the risk of high pressure equipment.Three,base earthing body: use the steel bar inside the building foundation,according to the requirements of "specification" connection low rpm generator alternator of grounding body called base earthing body.Some people think that,in the basis of reinforcing bar,concrete cover the impossible and the conduction of grounding body.Is,in fact,good insulation dry concrete and concrete in contact with the water of the soil containing water,capillary absorbs moisture to keep the concrete with high water content in concrete,and thus reduce the resistivity of the concrete with the earth if one.

Three-phase asynchronous motor winding fault analysis and processing

Winding short circuit Due to magnetic motor the large motor current is too large and the change of supply voltage and single phase operation,mechanical,manufacturing bruised bad insulation damage caused by such as winding interturn short circuit,short circuit between windings,winding interelectrode interphase short circuit and winding short circuit.1.The fault phenomenon Ion of the magnetic field distribution,unbalanced three phase current and make the motor vibration and noise when running,serious when motor can't start,and have great short-circuit current in coil of short circuit,lead to rapid heating coil and burned.

2.The reason Insulation insulation aging motor overload for a long time,lost;Wire insulation damage;Winding be affected with damp be affected with damp decreased insulation resistance caused by insulation breakdown;End and not cushion layer insulation material or plastic damage;End connection wire insulation damage;Or been struck by lightning overvoltage magnet prices insulation breakdown;Friction between rotor and stator winding end insulation damage;Too many metal foreign bodies fall into the inside of the motor and oil pollution.Methods to examine.

3.(1) the external observation method.Observation of junction box,winding end with or without burning,winding overheating after leave a dark brown,and has a bad smell.(2) temperature control method.No-load running for 20 minutes (found abnormal should immediately stop),with the back of hand touch winding parts is more than normal temperature.(3) the electricity experiment method.With current meter measurement,if one phase current is too large,have

indicated that the phase short circuit.(4) the bridge inspection.Measuring a winding dc

resistance,general difference should not exceed 5%,such as more than small,resistance of a phase

short circuit fault.(5) short circuit detection method.There is a short circuit the winding under test,the permanent magnet motors for sale sheet steel can produce vibration.(6) multimeter or megohmmeter.And any two phase winding insulation resistance measurement,if read very small or zero,shows that the two phase winding and has a short circuit.(7) voltage drop.After the three winding in series into the low voltage security alternating current (ac),the study measured a group of small fault.(8) current method.Motor no-load running,to measure the three phase current,in two phase switch,measure and contrast,if he does not change with the power switch,a phase winding large current has the short circuit.

4.Short circuit processing method (1) the short circuit point in the end.Insulating materials available to separate short-circuit point,also can be double insulated wire,to paint drying.(2) short circuit online slot.After the softening,find out the short circuit point repair,back into the trough,then paint drying.(3) the short route turns less than 1/12 of each phase winding,the serial number of turns all cut short route,connect the conduction part,forming a closed loop,supply urgent use.(4) winding short-circuit point when the number of turns more than 1/12,to dismantle all rewind.

Construction machinery used in motor maintenance rules?

(1) of the motor shell must make the pledge that we shall have good grounding or zero.(2)

periodically clean the machine work,purging of the compressed air,compressed air diesel

generatorshould be clean and shall not contain water and oil content,pressure should not

exceed 2~3 KGF/cm~2*1 KGF/cm~2 = 9.80665*10~4 Pa (3) the number of motor bearing grease should be stipulated by the original factory,no rules,should be combined with the working performance of the motor selection,filling quantity to be appropriate.(4) brushes,slip ring,or the processing of commutator and brush holder adjustment,must be a power outage.asynchronous motor (5) discontinued for a long acmotortrading.blogspot.com time and after the fault

treatment of motor,must by the insulation test qualified,can put into operation.Insulation resistance

shall meet the handover and the regulation of the preventive test electrical equipment in the

single phase generator regulations.Generally high voltage ac motor stator insulation

resistance should not be less than 1 M per kv ,rotor every 0.5 M kv; Low voltage of the motor stator

insulation resistance should not be less than 0.5 M ,rotor should not be less than 0.15 M.

Discrete space vector modulation method

No beat the direct torque control theory can maximize the elimination of torque and flux linkage

error,overcame the weakness with a Bang-Bang control inaccuracy,but need a larger amount of

calculation,and these are related to motor parameters,easy to cause the error in

calculation.Therefore proposed in the literature does not need much calculation,and can improve the torque and flux linkage control accuracy of discrete space vector modulation method.In the discrete space vector modulation method,and through the six basic two level inverter output voltage vector of the adjacent voltage vector and zero voltage vector for the synthesis of regular,as shown in figure 3 is the use of the adjacent single vector 2 and the single vector and zero voltage vector synthesized space voltage vector.Can be seen from the figure 3 its synthesis method is to put the average sampling period is divided into three segments,each segment is composed of non-zero voltage vectors or zero voltage vectors,such as space voltage vector z is 23 by the vector 2 and 3,a third and zero voltage vector of each sampling period can use five stages or 7 sections of mode synthesis (didn't),using the regular synthesis method can create 10 total voltage vector.acmotortrading.blogspot.com Elaboration of the voltage vector can be more accurate counter rotating torque and flux linkage control,in the literature on level 2 of flux using the traditional hysteresis Bang-Bang control,and turn into account Ac motor-South Korea SPG induction motor small motor series Ac motor-South Korea SPG induction motor small motor series Moment need fast dynamic response,the division of the level 5 hysteresis Bang-Bang control,as shown in figure 4,the error of different belt use different voltage vector table.

In addition,the author through the influence of voltage vector rotating torque change was derived formula is as follows: Can be seen from the type of ⑽ the same voltage vector in the influence of low stator winding machinespeed and high speed counter rotating torque changes are different.Therefore,in the different speed range with different voltage vector,as shown in figure 3.On the other hand,low speed using small amplitude of voltage vector and high speed using the amplitude of voltage vector is also in line with the V/f = C this rule.The traditional direct torque control in the low speed of continuous use more zero voltage vector switch frequency is very low,large torque ripple.According to the method of discrete space vector modulation due to the low speed using small amplitude of voltage vector,so the continuous use of zero voltage vector is little,high switch frequency,small torque ripple.In addition,due to the high speed of voltage vector is more,can be divided into 12 sectors,using two voltage vector table,it can be for more precise control.Can be seen from the above analysis,the discrete space vector modulation method is easy to implement,don't need any beat control as much as I would like to calculate,keep the traditional Bang-Bang control,the advantages of good robustness,therefore,but compared with the traditional direct torque control and can increase the torque and flux linkage control accuracy,reduce the torque ripple at low speed.But more to generator rotor and stator improve control accuracy and vector is divided into the thinner,the greater the voltage vector control table is more,this will increase the complexity of the control.So,if can let the discrete space vector modulation with no beat control,which will help you to overcome this shortcoming.

The shaded pole motor

Usually see single-phase motor are shaded pole motor,generally used in small devices start torque,such as electric fans and other small household electrical appliances.In this kind of motor,small single stage rotary concealed copper coils can produce a rotating magnetic field.Each

pole is surrounded by diesel generating copper coils or copper tape on part of the living;In order to prevent the current in the coil change (lenz's law) can produce induced current in the copper strip,so that every cycle maximum field strength across the surface,to produce a large enough lower rotating magnetic field to drive the rotor and the load on it.As the rotor increase its torque to the largest,the original (fixed) by turning the magnetic field will rotate with the rotation of the rotor.It is

difficult to reverse the motor unless internal structure change.Another common single-phase ac motor is the split-phase induction motor,such as washing machine and dryer is typically used for large household appliances.Compared with the electricalmotor1.blogspot.com shaded pole

motor,these motors can be started by winding and centrifugal switch connected together can often

provide a big start torque.In the split-phase motor,the design of the startup winding resistance than

the running winding resistance.This will generate a LR circuit,the circuit will slightly change the

phase of the current in the startup winding.When the motor is started,the start winding through a set of the above pressure with no rotation of the centrifugal switch spring connection on the power

supply.Winding start winding line is thin and less than used in the main winding line several

times,so it is a high resistance and low inductance.Low inductance and resistance rate produces a

small phase shift does not exceed 30 degrees,the phase shift is determined by the main winding

magnetic field lines and determined by the startup winding pumps magnetic field lines.Can run by changing the startup winding and winding connection to easily change the direction of rotation is

started.Start winding magnetic field phase as the grid phase changes,to produce a start the motor

rotating magnetic field.Once the motor reaches near design operating speed,the centrifugal switch

start action,shut off the connection between the startup winding to the power grid.Motor running by

running winding.Start winding must be disconnected,because it will increase the loss of the motor.