The analysis of the causes of transformer oil leakage reasons - environmental temperature change

Refer to instruction for use of current 8500w gasoline generator transformer,transformer running environment temperature 40 ℃,the highest temperature is + minimum temperature of 40 ℃. Our factory area this summer outdoor certainly higher than 40 ℃,the highest temperature field measurement of motor run capacitor the surface temperature is close to 50 ℃. After each part of the summer heat equipment thermal expansion,due electricalmotor1.blogspot.com to environment temperature drop after high temperature season,but all motor vehicle kinds of material shrinkage is not consistent with the temperature,cause the leakage of oil from the surface. This point in our plant is particularly prominent.

Why low voltage winding of transformer in the inside,and high voltage winding in the outside?

The arrangement of the high and acmotor2.blogspot.com low voltage transformer,it is decided by many factors.But for most of the transformer,low level around the layout in the high voltage winding is put inside.This is mainly from the insulation into consideration.In theory,no matter how high or low voltage windings to decorate,can be variable pressure role.But because the iron core transformer is grounded,due to the single phase generator low voltage winding is close to the core,from the perspective of insulation easy to do.If the high voltage winding is close to the core,is due to the high voltage winding voltage is very high,to meet the insulation requirements,requires very of insulation materials and the insulation of the large distance.Such not only increases the volume of small electric motors the winding,and waste of the insulating material.Moreover,as a result of the transformer voltage regulation is electrical motor to rely on change of the high voltage winding tap,namely change the number of turns,so the high voltage winding is placed in the low voltage winding outside,lead more easily also.

Machine tool equipment electrical troubleshooting - for appearance inspection fault area

In determining the scope of the possibility permanent magnet generator of failure,for within the scope of the electrical components and wires are appearance inspection,such as:the melt blown fuse;The location of the travel switch adjustment is not appropriate;Wire connector is loose or fall off;Contactor and relay contactor fall off or poor contact,coil burn 12v motor discoloring the burning surface electric motor insulation paper,flashing the insulating varnish outflow;Spring falls off or broken;Electrical switch,acmotortrading.blogspot.com etc.,the action mechanism of blocked failure can clearly show that point of failure.

The inverter no-load current is greater than the load current

A 75 kw micro can WIN-G9 inverter commissioning the strange phenomenon,Associated with the manufacturer's technical personnel a piece of paper,trying to find out the cause of the electrical and mechanical aspects.Whether whether new repair,such as motor winding winding bad; Bearing any permanent magnet generator wear and tear,unstable running; Is there a loose connection shaft and different heart phenomenon; The blades have deformation,etc.To restore the original start tank connection,power frequency power frequency starting motor do diesel generators prices contrast,one by one,ruled out the suspect,and according to the in-situ observation,the motor and the load status is good,can hardly hear the running of electrical and mechanical noise.Run at full speed under no load current is only less than 35 a,three-phase balance,no wave! No problem with the motor and load,the problem also in frequency converter.So of the frequency converter fault in where? 

A little scratching his head.Is that current detection not,cause error output? Observation panel displays the current value and clip-on ammeter measured near,there should be no problem.Or there is something wrong with the CPU motherboard,the output waveform is wrong? Makes no sense.Digital circuit ah,how waveform is wrong? Well,live not far electricalmotor1.blogspot.com from here have another same model with the power of change,with the load is the same,it would be great.It brought great convenience to the contrast test.The manufacturer in a hurry to opening up to the machine,also gives a positive cooperation.Will two inverter current transformer swaps,invalid.The motor vehicle two machine CPU motherboard swap shall be null and void.Bring up the main circuit,according to the dc voltage is 550 v,voltage sampling circuit also have no problem.Never figured out where fault block circuits.Compare the machine in the load cases,10 hz running current is 75 a,more than 35 hz,running current to reach 100 a,smaller than this one with no-load current of motor.No-load current was far greater than the load current,the frequency converter must be have a problem.

General converter electrical engineer to teach you the overcurrent

General converter electrical engineer to teach you the overcurrent protection and treatment methods Overcurrent protection function of the frequency converter is a very important role in the frequency converter,the following introduce you to the cause of the over current and processing method Frequency converter in the overcurrent protection object refers to with paroxysmal qualitative,peak current,exceeds the permissible value of frequency converter.As a result of the inverter device overload ability is poor,so frequency converter overcurrent protection is a vital link,so far has been very perfect.(1) the cause of the over current A.over current work The current system appeared in the process of work.The reason for this is roughly from the following aspects: A) motor encounter impact load or drive mechanism to the sudden increase of motor current phenomenon of "stuck".B) inverter output short-circuit,such as the connecting line between the output to the motor motor internal short circuit or short circuit,etc.C) inverter itself is not normal work,such as two of the same bridge arm in inverter bridge inverter device in the process of alternating work abnormal.For example due to environment temperature is too high,or aging,the inverter device itself to change the parameters of the inverter device,cause in the process of alternating,a device has been conducting,and another device but also in the future and shut off,causing the same bridge arm of the upper and lower two parts of "straight",the dc voltage between the positive and negative in the short circuit state.

B.over current acc When the load of the large inertia,and set up time and too short,means in the process of advance,the working efficiency of the converter rise too fast,the synchronous speed of the motor because of the large inertia load and couldn't keep up with,and the result is acc current is too big.induction motor price C.over current slow down When the load of the large inertia,and slow down the time set too short,can also cause overcurrent.Because of the slow down,the time is too short,synchronous speed drops rapidly,due to the load and the motor rotor inertia is big,still maintain a high speed,then the same can be the speed of the rotor winding cutting lines of magnetic force is too big and over current generation.(2).Treatment methods A -.When starting A liter of tripping speed,this is very serious phenomenon over current,major inspection (1).Working machinery have stuck (2).Load side if there is any short circuit,check over the ground by megohmmeter for short motor fan circuit (3).The inverter power module if there is any damage (4).The starting torque of the motor is too small,the drag system turns up B.starting without tripping immediately,and tripping in the operation process,the main check: (1).Set up time is too short,longer acceleration time (2).Deceleration time setting is too short,longer deceleration time (3).Torque compensation (u/f ratio) set too big,cause the low frequency time load current is too large (4).Improper electronic thermal relay setting,current action set is too small,misoperation caused by frequency converter

The analysis of the causes of leakage of transformer oil - seal structure

I plant oil leakage current transformer are mainly concentrated in four period of current transformer installed in the switching station,four period of current transformer is hunan liling cichang the mid - 90 - products,has been running more than eight years.Current transformer porcelain jacket with expander and motor magnet tank adopts hanging flange connection,this structure has to be eliminated,manufacturers are now used for pressure coil flange connection,compared with the hanging type connection,pressure coil flange connection has the advantage that can make the flange surface stress more evenly.

Manufacturers motor run capacitor of technical improvement,also can prove the existence of hanging join some shortcomings. Current transformer primary winding through the upper porcelain set of four terminals,derivation from the scene of the collapse of the transformer terminals can be found electricalmotor1.blogspot.com at a time,a terminal nanjing cichang the production of transformer and porcelain set of seal,the internal and external two flat pad.And a terminal liling,cichang production of transformer seal only outside a plane pad.Sealing structure differences make liling,cichang transformer produced a joint terminal sealing surface oil leakage occurred frequently.But now the liling manufacturer has also made the improvement to this sealing structure,in electrical motor a terminal seal face to add a seam allowance,o-rings seals,how to be in one step.

Three-phase asynchronous motor efficiency and power factor

 Induction motor efficiency and power factor is contradictory.For the same kind of Y series motor,high efficiency,low power factor.On the other hand,low efficiency,high power factor,high power,good for motor use;The power factor is low,will reduce the network transmission efficiency,because of low power factor,so the grid reactive power loss is big.So for ac induction attack efficiency indicators put forward higher requirements of wholesalemotor.blogspot.com both,puts forward higher requirements to the power factor index.The efficient and high voltage three-phase asynchronous motor,it overcomes the defect of old asynchronous motor,its insulation thickness thinning by the original unilateral 1.5 mm to 1.3 mm;Innovation design of star - Angle joint series hybrid hard winding method,reduce the stray loss of the motor,greatly improving the efficiency of the high voltage motor;Motor efficiency is low,the loss is big.For ac motor,is the resistance loss,in this way,the greater the loss of P in the power triangle,the greater the power factor Angle phi is smaller,the greater the power factor cos phi.Conversely,high efficiency,low loss,P is in the power triangle is smaller,the power factor Angle phi is smaller,the power factor cos phi is smaller.In order to satisfy the motor power factor,efficiency,two indicators,the backward of the structural design of centrifugal fan,a significant reduction in the high efficiency high pressure loss in the three-phase asynchronous motor machinery and noise.

The efficient high-voltage three-phase asynchronous motor can not only improve the work efficiency of the motor,and can also achieve the goal of reducing energy consumption,will be widely used in power stations,petrochemical,urban water supply,cement,paper making,metallurgy,coal and other industries,has an extremely extensive application prospect in the market,has significant economic and social benefits.Shell directly related to the personal safety and equipment protection grade selection of reliable operation,should be based on motor using occasions,to prevent human exposure to the motor internal dangerous parts,prevent solid foreign body into the chassis,prevent water from entering the shell cause harmful effects to the motor.Motor by letters IP protection grade plus two characteristics of Numbers,the first characteristic figures show that Motor vehicle the solid proof,the second feature figures show that the liquid.It is widely used in industry and People's Daily life.This kind of motor stator system group composed of group working system and starting winding.Its working principle are similar to those of three-phase asynchronous motor.The author through the analysis of the working principle of the single-phase capacitor motor to illustrate its positive &negative or transform a one-way operation of single-phase capacitor motor for positive and negative transfer lines of practical control circuit.

A.Simple working principle 1.When you don't answer the capacitance starting winding can a single phase or three phase asynchronous motor starting or running conditions,in terms of this item is set to the current in the winding of motor in whether can produce a rotating magnetic field.If not in the starting system group of the single-phase capacitor motor concatenated appropriate capacitor Tend to attend.If you want to improve the power factor,should reduce the motor air gap,increase the serial number of turns per phase.And rotor balancing machine to improve efficiency,increase should be ac motor air gap,which can reduce the harmonic stray loss,due to the harmonic stray loss and air gap of 1.5 ~ 1.6 power ratio.The two measures the reverse.When turn the timer can't start again,to the motor shaft by hand a little at this time can turn the rotation of the external force.After inspection found that the washing machine in the two capacitors,there is a short circuit phenomenon in a capacitor,the only change after short circuit capacitor in the same specification,then turn the timer when the normal operation of washing machines.In the washing machine motor is the typical positive &negative use capacitor motor control mode.Single-phase capacitor start motor is one of the single-phase asynchronous motor.

Electrical engineer for the selection of step motor

 

Stepper motor can transform electrical pulse signal into angular displacement or linear displacement.In the range of the rated power of the motor speed depends only on the pulse signal frequency and pulse number of control,and not affected by load change,coupled with step motor characteristics of cumulative error is small,in areas such as speed,position with stepper motor to control becomes simpler.Stepper motor three kinds,mainly is the hybrid stepping motor is widely used.When choosing a stepper motor,must pay attention to the following parameters as the manufacturer (are supplied with the motor):Step 1) from the Angle of: after receiving a step pulse motor rotation Angle.The actual interval Angle and fine fractions of the drive.Generally the precision of the stepper motor to step away from the Angle of 3-5%,not cumulative.2) number: the inside of the motor coil set number.Step phase number is different,is apart from the different Angle.If using subdivision driver,'phase number does not make sense: change the fine fraction can change electric motor cooling fan interval Angle.3) keep the torque: also called the largest static torque.

Refers to the rated power flow speed is zero,the external force force needed for the rotor rotational torque.Keep the torque has nothing to do with the drive voltage and drive power supply,etc.Stepper motor at low speed torque close to holding torque.As a result of the stepper motor output torque and power increases with the speed and constantly changing,so keep the torque is measured step motor is one of the most important parameters.Although holding torque is proportional to the electromagnetic excitation ampere turn,with the air gap between the rotor teeth.But too much by reducing the air gap,increasing the excitation ampere turns to improve static moment is not desirable,it will cause heating of the motor and the mechanical noise.Keep the torque type determined as follows: Stepper motor dynamic torque a while it is difficult to determine,tend to make sure the static torque of motor.Static moment of choice was based on motor work load,the load can be divided into two kinds of inertia load and friction load.Single inertial load,and there is no single friction load.Order more (generally by low speed) when (suddenly) starting when the two kinds of load are to consider,when accelerating (slopes) starting main consideration of inertia load,constant speed run into as long as considering the friction load.In general,keep the friction load torque should be within diesel generating set 2 to 3 times as well,holding torque once selected,motor frame and length can be set down.

The purpose of the motor

Motor USES many to heavy industry,and a small toy,in its tracks.In different circumstances can choose different types of wholesalemotor.blogspot.com motor,the following are some examples: The wind device,such as electric fans Electric toy car,boat,etc Elevator,the elevator With electric powered vehicles,such as underground railway,trams Automobiles,jet and helicopter starting motor (starter motor) Factory with big lots of conveyor belt The electric automatic doors on the rotor balancing machine bus Electric roller shutter Consumer goods drive The printer The washing machine The water pump Disk drive Electric shaver The tape recorder Video camera CD players Industrial and commercial purposes Express elevator Machine tools (such as: machine tool) loom 8500w gasoline generator A blender.

Cause of standard section connecting bolt looseness

Cause of standard section connecting bolt looseness are:mixed installation team personnel,without training,technical quality is uneven,not according to the requirements of construction lifter specification operation,safety awareness is weak;For the provincial process,using the hoisting machinery auxiliary conjoined assembled parts installed,or the standard section on the surface of the assembled integral hoisting,after inspection on connection bolt without fastening;Hand after temporary fixed screw bolt acmotor2.blogspot.com tightening,no longer bolt not use gaskets;Fastening bolt tool is simple,did not use professional torque wrench,short of bolt fastening value;Helped wall after completing the first nut bolts,and the scene the cap number is not enough,back cap missing or not tighten. Helped wall bolt hole is too big,did not use more than electric motor cooling fan 100 x 100 mm 60 mm thick steel gasket;Use of ordinary bolt temporarily use does not change in time. Helped wall bolts are mostly use double-headed screw,and no marked strength,use length,double nut can't tighten;Non-standard professional unit self-check,the acceptance is not serious;Daily use do not timely check and tighten,repair,maintenance,lead to loose bolts,etc.

Second,the elevator installation specification requirements Construction lifter standard section is the spine of the elevator,carrying the weight of the machine itself and cargo movement,the hoisting cage depends on the post up and down reciprocating wheel attachment for standard section,so ac motor electric 65kw attached wheel interface connection,enables the wheel to balance force. Wheel and rack and the place such as transmission mechanism of gear meshing size have the higher requirement of its technology,make sure that the standard section pillar tube joint fault status difference,respectively,0.5 mm and 0.3 mm or less,or less at the same time,the adjacent two rack joint along the direction of tooth difference of 0.3 mm or less,along the length of the tooth difference should be 0.6 mm or less.On the standard section of guide rail and rack column for the first time after installation bolt screw die or have a rivet head. Standard section permanent magnet motors for sale function and requirements of each production manufacturer and requiring less random text file,standard and theory of standard section is not detailed,the expression of the usual safety education,safety inspection and technical clarificaiton,less to this requirement. 

Installation and removal of personnel the subconscious thought standard section strong deformation can not easily,but there is no detailed check for standard section of the wall thickness,therefore in the standard section conjoined assembled parts assembly neglected the connecting bolt fastening.Elevator in the process of installation standard section,section of up to 9 meters high adhesion after installation,the installation of the standard section with conjoined assembled parts are,bolt pseudo screw fixation can be buried. Hanging basket load up and down reciprocating motion acceleration is loose easily guide system two guide verticality and guide the error of the centerline of the overlap is greater than 2 mm,influenced by and other forces,at this time would be a counter weight to run a block or thrown,rope,wire rope guide wheel clearance of large and small. Actuator motor after repair,the rotation speed mismatch cause the vibration of hoisting cage and noise increases,hysteresis shouldn't run into events. Elevator conjoined assembled parts installation operation standard section,to the frequent work of elevator running buried the curse. To resolutely put an end to this is not in conformity with the specification requirements of the installation operation,to regulate the behavior of equipment installation and use.

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.

From time to tome noise motor

Mechanical parts and electromagnetic part of motor fault points,distinguish method: first to make the motor operate,carefully listen to the voice of the running,and then a power outage,let the motor inertia magnet motor continues to run,if not normal voice disappear at this moment,that is the motor electromagnetic fault,otherwise is motor mechanical failure.Mechanical noise,A noise from the bearing,may be damaged bearing ball,lubricating oil is too little,then A screwdriver head outside the bearing oil was built,petiole near the ear,can hear the sound of loud gurgling.B air noise was generated.The sound is very uniform,is not very strong,can be judged as normal.

C electric JiSao chamber caused by noise,the noise features a scrape of a sound,for the motor,have just completed the runtime if find any noise,can check to see if the current balance,www.dongfeng-motor.com the rotation is flexible,speed up to rated speed,above if no problem,may be in the stator slot insulation paper or bamboo chip slit,protrudes from the rotor instead of the mo was found when the sound is characterized by both sharp rotor and stator and high.Electromagnetic noise: A bad cooperation length of rotor and stator,the rotor length refers to A bearing to another bearing distance,the length of the stator refers to from A bearing chamber to another the distance of the bearing chamber,under normal generator stator circumstances,the stator length slightly longer than the rotor length,such as vary too much,may be A low "om" sound.B the rotor axial displacement,the displacement of electromagnetic noise can occur,and cause the no-load current increases,the battery performance of the motor.C of the stator,rotor slot number mismatch,the wrong loading other rotor assembly process.D breath uneven between stator rotor,stator rotor circle,also may be a slight bend axis,etc.Lack of phase,in addition,the motor winding interturn short circuit,phase short circuit,overload operation,etc all can cause electromagnetic noise.

Name explains two

 1,high voltage test pen:used to check the high voltage distribution network equipment,overhead lines,cable whether electric tools.2,grounding line,to the surprise appearance has power equipment and line voltage single phase ac motor to ensure staff's important tool.According to the provisions of the enterprise in ground wire must be at least 25 mm 2 bare copper cord.3,sign:used to warn people not close to the equipment and charged part,instructions for personnel work,remind to take safety precautions,and banning trace a device or a period of circuit switching power on board.Can be divided into the warning classes,allowing,prompt and banned the and so on.4,covering bar:to prevent staff had no intention of encounter charged equipment parts and equipment screen protector,temporarily hide column and permanent column two.5,insulating rod:also called the www.facebook.com/dongfeng.motor g rods,insulating rod,operation,etc.Insulating rods by working head,insulation and handle three parts.

It in a closed or open high-voltage isolating switch,portable earthing line installation,as well as the measurement and test.Step 6,:if the ground horizontal distance of 0.8 m has a potential difference between two points,when the two feet of human exposure to the two points,in the human body will withstand voltage,the voltage is called the step voltage.The biggest step in from the ground of the grounding body between the grounding body and horizontal distance of 0.8 m.Is 7,phase sequence,phase sequence,is an alternating current instantaneous value changes from negative to positive after zero order in turn.8,the power grid,power grid is part of the power system,it is made of all kinds of transformer substations (by) and different voltage grade of transmission,power 5kw permanent magnet generator distribution lines connected to form a unified network.9,electric power system,power system is a part of power system,it is composed of power plant generators and power distribution equipment,step-up and step-down substation,transmission and distribution lines and the users of electricity equipment.10,power system,power plants,substation mini electric motor and power users of electricity equipment,and its to the power grid and the thermal network (or hydraulic) system connected is called dynamic system as a whole.

Submersible pump motor repair 10 points for attention

 Mine submersible pump motor electromagnetic part and ordinary motor basic same,therefore,electromagnetic failure and repair,but due to the particularity of explosion-proof motor.In carries on the repair or reconstruction,it shall comply with the following provisions: The relevant personnel should understand,repair units and the relevant national laws and regulations,explosion-proof standards for repair work and the relevant provisions of the qualified products.Second,the unit should have for explosion-proof motor repair process equipment and the necessary inspection and test apparatus.Before three,maintenance,should prepare the necessary technical data.Four,commissioning before the motor repair,check the cable entry,relay protection and wiring system,to ensure that the company is still in good condition and conform to the requirement of explosion protection.Five,to engage in explosion-proof motor maintenance personnel should undertake the necessary training.After six,after inspection and acceptance of the inspection items,is made by authorization of the explosion-proof test unit or recognition,can be in repair units; 

Think it is necessary to project still explosion-proof test unit by explosion-proof inspection unit.After repair,explosion-proof motor should be to use the department to provide the following documents: 1) fault inspection;2) repair work instructions;3) Motor vehicle replacement and repair parts catalog;4) inspection and test results;5) repair certificate.Eight,are not allowed to repair the piano pieces 1) by the size of glass,plastic or other unstable parts made of materials;2) fasteners;3) the manufacturer or explosion-proof code that can't repair parts,such as encapsulation component.A sign of nine,after the repair will not affect the explosion-proof performance of repair,after repair without repair.Ten,the flame-proof certification after after repair motor repair the repair unit inspection department shall issue certificate of approval.Described above shall include at least by repairing the name,type,specification,water pump explosion-proof motor logo,the name of the class units and its approval certificate number,explosion-proof certificate number,date of repair,etc.The standard code for GB3836.13-1997 after the repair.Signs must be norm,durable,and resistant to chemical corrosion.Signs should be metal materials,commonly permanently fixed on the motor after the repair,repair again,after repair,the previous repair sign shall be removed.

Capacitance recognition

1,the capacitance in circuit "C" and is commonly used in digital representation (such as a capacitor C13 said Numbers for 13). Capacitor is made up of two pieces of metal film,close to the middle separated by electric motors 12 volt insulating material and components. The characteristics of capacitance communication mainly blocking circulation. The size of the capacitance is said to store electrical energy,the size of the capacitance effect is called the capacitive reactance of ac signal,it is associated with the frequency of the ac signal and capacitance.Capacitive reactance XC = 1/2 PI c f (f is the frequency of the ac signal,capacitance c said) is commonly used in telephone with electrolytic capacitor,the kinds of ceramics capacitors,SMD capacitors,monolithic capacitors,tantalum capacitors,polyester capacitors,etc. brake rotor 2,capacitance recognition methods: identification method of capacitance and resistance identification method of basic same,straight standard method,three kinds of color standard method and standard method. 

The basic unit of capacitance with ferrari (F),according to other units include: milli single phase electric motor method (mF),micro method (uF),sodium (nF),leather (pF).Among them: 1 q = 10 3 mm = 10 6 micro method = 9,10 = 10 12 leather method of large capacity capacitor on capacitance directly to mark its capacity values,such as 10 uF / 16 v capacity small capacitance of its capacity value with letters or Numbers on the capacitance letter notation: 1 m = 1000 uF p2 = 1.2 PF 1: n = 1000 PF digital wholesalemotor.blogspot.com representation commonly used three figures show that the size,two significant figures,said before the third digit ratio. Such as: 102 said 10 x 102 = 1000 pf pf said 22 224 x 224 = 0.22 uF pf 3,the capacitance error table F G J K L M allowed error of plus or minus 1% plus or minus 2% plus or minus 5% plus or minus 10% plus or minus 15% plus or minus 20%,such as: a ceramics capacitors for 104 J said capacity of 0. 1 uF,the error of plus or minus 5%.

Three-phase asynchronous motor winding short circuit

Due to the large motor current is too large and the change of supply voltage mini electric motor 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.Fault phenomenon: 1.The magnetic field distribution of ions,three phase current balance and make the motor vibration and noise when running,serious acmotortrading.blogspot.com 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: motor overload for a long time,lose insulation aging of insulation;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 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.

3.Check: (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 ac electric motors 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 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 electric motors price 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.

Ammeter pointer during no-load or load running back and forth

1),2) squirrel cage rotor broken bar,a phase winding rotor circuit (3),a phase of wound rotor type motor brush contact bad 4),wound rotor type motor Poor contact slip ring wholesalemotor.blogspot.com short circuit devices 9.The cause of motor vibration 1),2) unbalanced rotor,shaft bending head 3) 4),imbalance of pulley,pulley eccentric shaft hole 5),fixed the loose bolts 6) of the motor,fixed The acmotortrading.blogspot.com foundation of the motor not firm or uneven 10.The cause of the motor bearing perkins diesel generator set overheating 1),2) bearing damage,lubricating oil too much,too little,or oily bad with 3),bearing and perkins diesel generator set shaft too loose walk in circle or too close with 4),bearing and end cover too loose walk outside Or too close.5),sliding bearing ring rolling or slow rotation 6),on both sides of motor end cover or bearing cover is not flat 7),belt tight 8),coupling packed Not good.

General stepping motor

General stepping motor has eight root lead.It can be configured for single polarity can be configured to bipolar stepper motor.In resolution of this kind of stepper motor windings may cause some confusion,users because of wholesalemotor.blogspot.com the need to master the correct winding polarity and order.Usually,just rely on observation is unable to determine the polarity of the winding.Fortunately,you can through the electronic measurement method to infer it.1.Distinguish general stepping motor winding polarity In order to measure and determine the general stepping motor winding polarity,need a power supply or battery,and a digital multimeter.Please follow the following steps: (1) first of all,using a digital multimeter ohm file to find four leads,and to identify four windings.(2) choose two windings,and generator stator each choose a lead short answer to each other.Will switch to the digital multimeter AC voltage 20 v,connect the two pens and a digital multimeter to measuring the two ends of the winding.

3.Turn the motor shaft,if the get 2 v voltage reading,then found the same set of winding and also determine their polarity f figure of 81.If the multimeter reading is 0 v,as well as determine the polarity of the winding,the reverse polarity f they see electric motors price figure 9).Switch to the winding of the other fuses and short received another winding,in order to verify the previous assumptions.(4) with lead to indicate the polarity of the windings.As to which side as the above graphic mark of black spots in the end it doesn't matter,as long as you know how to group.2.The configuration method of general stepping motor polarity This section about configuration of general stepping motor polarity of three ways: single polarity,bipolar series and bipolar parallel.As shown in figure 10 configuration simulates a single polarity of single phase asynchronous motor the six winding stepper motor.Shown in figure 11 bipolar configuration can work at a relatively low frequency high torque.Its working frequency cannot is higher,because the series winding with high magnetic resistance,peak current,therefore,cannot fast.Dual polarity is shown in figure 12 parallel configuration the output torque is less than bipolar stepper motor cascade configuration,but it has higher operating frequency,because of the parallel winding configuration has a low magnetic resistance,peak current can be quickly.

The principle of three phase asynchronous motor

When to three in the stator mini electric motor winding through a symmetric three alternating current (ac),creates a to synchronous speed n1 along the circle space inside the stator and rotor rotate clockwise rotating magnetic field.Due to a rotating magnetic field in the n1 speed rotation,the rotor conductor is still at the beginning,so the rotor conductor will cut the stator rotating magnetic field and induced electromotive force (judge the direction of the induced
electromotive force with the right-hand rule).Because the guide was short circuit ring short meet on both ends of the conductor,in under the action of induction electromotive force,the rotor conductors will be wholesalemotor.blogspot.com consistent with the direction of induction electromotive force induced current.Rotor current carrying conductor in the role of the stator magnetic field by electromagnetic force (judge force direction with the left www.dongfeng-motor.com hand rule).

Electromagnetic force to the rotor shaft of the electromagnetic torque,driving rotor spinning in the direction of the rotating magnetic field.By analyzing the working principle of the motor can be summarized as follows: when the three motor stator winding Angle of 120 degrees (the difference between electric),bubbled into three alternating current (ac),will produce a rotating magnetic field,the rotating magnetic field cutting rotor winding,thus produce induced current in the rotor winding is closed (rotor winding path),the rotor of current-carrying conductor under the effect of the stator rotating magnetic field will produce electromagnetic force,as to form the electromagnetic torque on the motor shaft,motor rotation,and the motor rotation direction gasoline generator is the same as the rotating magnetic field direction.

The difference between motor and brushless motors

From now in general use in the industry,there are two main types of motor:efficient rare earth permanent magnet has a motor and the efficient rare earth permanent magnet brushless motor on the market at present most Electric bicycle is still stay in brush motor stage.A brush motor using mechanical commutation,the technical requirements of the control system is low,relative cost is lower than the brushless motor,A brush motor starting torque slightly larger than the brushless motor. But the fatal weakness is:life is short,large noise and low efficiency.Long-term use of carbon brush wear serious,it is easy to damage.At the same time wear produced huge amounts of carbon dust,These dust fall in gear oil,gear oil accelerate dries up,the motor noise further increased.A brush motor use to within a year or so will need to replace carbon brush,You will find a charge mileage bought less than two-thirds,and climbing when power is insufficient,will burn out the controller.This is because the motor After the replacement of carbon brush and commutator also be ground out a groove,reduce carbon brush contact area,poor contact of carbon brush after electrify which sparks and accelerate oxidation in electricalmotor1.blogspot.com To implement and copper,acmotortrading.blogspot.com lead to the undesirable phenomenon. Brushless motor electronic commutation replace the mechanical commutation,technically superior to brush motor.

Because of brushless motor without gear or gear,the motor,reduce wear and tear The unreliability.Its efficiency within a certain range of current ratio has a brush motor with high efficiency.Brushless motor driving up almost no motor lamination noise,and for up to 10 years to life On.According to the comparison,both brushless motor is better than have a brush.At present,there have been some electric bicycle factory with motor is to switch to the original brushless electric Machine.Brushless motor must be the development direction of electric bicycle. Consumers can come up from appearance to identify motor belongs to "brush" or "no brush" :first,"brushless electric wire" eight root,and the "brush" electric wire to the positive and negative There are two root;Secondly,with the induction motor hand when the drive motor,before and after the brushless motor rotation is easy,and before the "brush" motors turn easily,after when transfer is quite tight.

How to do short circuit test of the motor?

Short circuit test is to use braking device,the motor rotor fixed don't turn,three-phase voltage regulator output voltage from zero values increased.When the current reaches the mini electric motor rated current of the motor is stop booster,when the voltage is called the short circuit voltage.The rated voltage of 380 v motor its short circuit voltage is in commonly 75 ~ 90v.High impedance voltage said leakage reactance is wholesalemotor.blogspot.com too big.Short circuit voltage electric motors price is too low said leakage reactance is too ac electric motor small.Both for normal operation of motor will be unfavourable.