Three-phase no-load current of 2.5 0.75 KW motor,what reason be

Two sets of 0.75 KW...Grade 4...380 v...The motor.No-load current is between 2.3 to 2.6...Work environment textile...'a lot...Rated current of the motor is only 2.2...Normal no-load current is around 1.6...Time machine completely under the condition of no load over current...Due to the current big.So high temperature sharply born...Will soon.motor magnet Overheating damage...Please say the reason...thank you Problem complement: I thank two answer first...Disease,and together,the two are not normal before.In a few years later.

You'll find the bad one current is increased.[.Repair of the motor are friends.Eliminate offline ribbon...Until now,with or without load...motor run capacitor Motor current is bigger...Last year when the motor current in 2.0 A...Now 2.4-2.5 A...Motor shaft sleeve inside and outside in good condition...Have not completed...Don't go...Just electric pilot time to run the old hot...Often the temperature in the 60-80 degrees...Wiring is right...electricalmotor1.blogspot.com Are the normal installation...There is a reason,is you pick the wrong wiring.380 v y connection.You make into 380 v delta connection.So,motor heat quickly.This is one of them.In addition,the machine is idle for motor vehicle a long time,must have certain load.If is in use after a period of time (excluding intervention had gone wrong),should be the result of mechanical failure.1 bearing damage increase torque resistance.Run 2 bearing outer ring,which leads to the bearing wear gaps (cover),the rotor eccentricity running and friction with the stator (boring),increase the torque resistance.

Electric equipment maintenance procedures

 Oil-immersed transformer maintenance procedures are in operation or shutdown transformer routine maintenance once a year,stop running transformer increase maintenance once before put into use. Maintenance steps:(1) off to maintain the low voltage side of transformer circuit breaker,pull the isolating switch,hang on the permanent magnet motor corresponding sign.(2) disconnect the transformer high side load switch,confirmed after the disconnected position on grounding knife,and complete the switch security insurance and hanging sign.(3) into the transformer oil chamber,the first application of high-pressure electroscope to confirm whether the station transformer in the ac induction motor power state,and then pulled high voltage isolation knife,check the shell,porcelain and lead any deformation phenomenon,there is any breakage should be replaced,the oil level is normal,if there are any oil leakage phenomenon,should replace the rubber gasket,check whether the silica gel is effective,if there are any discoloration or serious failure,should be replaced immediately.

(4) retightened lead terminal,pin,grounding screw; Screw into the line,if there are any loose,should remove the screw with a flat file file interface,touch no uneven feeling after use clean cloth to wipe the dust,wipe on vaseline,change new spring washer,tighten the screw.(5) check whether the lighting,cooling and dust removal equipment surrounding the transformer is in good condition,with a clean cloth wipe away the diesel generators prices dust on the transformer body and vases.(6) check the transformer high side load switch,to ensure the flexible operation,good contacts,transmission part of the lubrication process.(7) 2500 v of the shaking table was used to measure high and low voltage transformer coil insulation resistance (to) and alternate with,in order (at room temperature 30 ℃,1 okv transformer high voltage side is more than 20 m Ω,low voltage side is more than 13 m Ω.Before the test,can good grounding wires,determination to end,should be discharge.

(8) check whether there is any legacy tools on transformer room and www.facebook.com/dongfeng.motor transformer,and verified,and on the high side isolating switch,evacuate the scene.(9) pulled high voltage earthing knife,after check grounding in the off position correctly,closed high-voltage load switch,let the transformer,and remove the high pressure side id CARDS,pay attention to in the open or close the transformer high voltage load switch,the site must have at least two people.Record maintenance results in detail,after delivery document preservation.(10) of the dry type transformer maintenance procedures and maintenance of oil-immersed very much the same. Maintenance of transformer's note: to ensure the use environment of transformer,in the absence of corrosive environment,the environment temperature should be within the - 30 ℃ to + 40 ℃,wind speed is not more than 350 meters per second,in the transformer high voltage side such as high voltage load switch,the operator should be three-phase transformer side short sub,and makes operation records at any time.High voltage transformer operating personnel should wear insulated shoes,wear insulated gloves.To prevent the transformer in the power and the transformer job mother discharge of electricity.

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.

Some problems that should be paid attention to when the PC program

The application of programmable controller (PC),we often encounter of the relay control system transformation problem,then we tend to refer to the original relay control circuit to prepare the PC application. In programming,therefore,we should pay attention to the PC electrical motor control system and relay control system some different on the way to work.Because of the relay control system is a "parallel" way to work,and its contact on-off needs certain action time. So when the starting circuit,time relay KT delay time,KT whether can continue to ac induction motor keep the current state,"parallel" two actions need to be considered at the same time process: KT normally closed delay off contact,KA1,losing electricity KA1 normally open contacts disconnect; KT normally open delay contact closure,KA2 electricity,KA2 normally open contact wholesalemotor.blogspot.com closure. The results of the two process function,to determine the status of KT. At the same time,the existence of the action time of the contact,makes the circuit in time sequence. So the circuit can not reliable work. If join the empty boxes in the loop,and as shown in high efficiency electric motor figure 1 the KA2 normally open contacts into KA3 normally open contacts (see figure 1) brackets. As a result,KT,the KT itself lost electricity,will not continue to maintain current state.

electric starting motor common fault analysis and maintenance of failure

When electric power,the motor does not work,and the motor without any sound.To analyze its main reason is the permanent magnet motor starter motor matching with electric equipment,if the electric fan,fan,washing machine motor adopts capacitor start running,and refrigerators,freezers starting mechanism adopts resistance split-phase start running,so once starting ac induction motor capacitor in the circuit and phase splitting resistance damage destroyed,seizing work,lead to motor testing should be excluded when starting or resistance after failure,to check the motor fault.Another case is inside www.facebook.com/guohong.trading the motor winding short circuit,partial winding burned,cause the motor to stop working.


When there is a failure in the once suspected the motor itself,the most simple detection with multimeter resistance of the winding resistance measurement.Will first motor three root lead ABC use multimeter to distinguish the judgment,here in double barrel of washing machine motor,for example,when measuring the resistance value between AB in 95 ohms,resistance value between the BC in 130 ohms,AB resistance in 12 ohms,so it is easy to determine the C for linear,AC for running winding,BC for starting winding.Above all is normal of the motor winding resistance value,in the event diesel generators prices of a short circuit,the resistance value are less than the above normal,motor windings of various kinds of problems.Again like a refrigerator motor starting winding short-circuit,23 ohm resistance around,no running winding short circuit,resistance value between 10 ohms,starting and running the concatenated winding resistance in 35 normal ohm.

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.

Electrical fault

 Has become more and more widely used in the production of electrical equipment,and electrical failure is inevitable,how to search and eliminate electrical fault according to the fault phenomenon is facing a big problem.Electrical maintenance personnel is to face and solve the outstanding problems electrical motor of the main technical force,in actual production application can accurately locate the fault,and troubleshoot make electrical equipment can steadily run normally every maintenance personnel is fork service motor run capacitor and responsibility.The article illustrates the general steps of electrical troubleshooting and troubleshooting methods.In the practical work,we will meet different electrical fault,the generation of electrical fault electricalmotor1.blogspot.com is strange,troubleshooting methods and ways can only according to the specific situation of the fault,no strict mode and method,will be difficult for part of the maintenance personnel,in the process of troubleshooting,tend to go asynchronous motor a lot of detours,even cause bigger loss.As a maintenance electrician,in case of electrical failure,can accurately find out the cause of the problem,reasonable troubleshooting correctly,to improve labor productivity,reduce the economic loss and safety in production is of great significance.