The estimation of three-phase ac asynchronous motor rated current

Whether need to reverse braking mode;6.Use environment and conditions,in indoor or

outdoor,temperature,humidity,size,how much dirt or dust,corrosive gas,explosive gas or liquid such as fever or smoke.Possible reasons: the power supply voltage is too low,three-phase ac asynchronous motor rated current estimates under the rated load caused by temperature rise is too high;Poor ventilation Or the environment humidity is too high;Motor overload or single phase operation;Number of frequent motor starting or positive &negative too much;Stator and rotor phase.2.4 low insulation resistance.Possible reasons: winding be affected with wholesalemotor.blogspot.com damp be affected with damp or pour water into the motor internal;There is dust on winding,oil engine-grease;The stator winding insulation aging.Often encountered in the practical work of agricultural machinery with dynamic problems,that is The choice of three phase asynchronous motor.On the premise of meet the requirements of production machinery,the basic principle of choosing motor is practical,economic and security,there are four factors to consider: type,rated power,rated voltage,rated speed.A,familiar with the requirement to the power of agricultural machinery to understand: (1) driving load the required power;(2) the type of work load,the load Is a continuous work,a short work,work load change or intermittent,etc.;(3) whether you need load demand work speed and speed regulation,there is a

speed adjustment and stepless speed regulation,etc.(4) starting way,frequency;(5).Second,according to

the requirement of the load motor asynchronous motor with squirrel cage and winding type two

kinds,selection method is as follows: 1) priority choose low price, Simple structure,convenient

maintenance of Y series three-phase ac squirrel-cage rotor asynchronous motor,but the downside is

speed control difficulty,low power factor,the starting performance is poorer.As a result,the

three phase generator mechanical properties is hard and no special requirements of the general production machinery and drag,such as agricultural and sideline products processing,ventilator,conveyor,conveyor belt,water pump is widely used in production machinery Pan.

The basic structure of three phase asynchronous motor three-phase asynchronous motor is made up of stationary stator and pivoting of rotor in two parts.A.the stator's structure: the three-phase asynchronous motor stator consists of frame,the stator core and stator

winding.B.rotor structure: the three-phase asynchronous motor rotor by the rotor iron core and rotor

winding and the rotor shaft parts.C.three-phase asynchronous motor by the bearing cover,junction

box,end cover,the stator core,stator winding,shaft,bearings,rotor,fan and casing.Common fault analysis 2.1 2 motor starting difficulty,rotational speed is low.Possible reasons: low power supply voltage;Originally the Angle of by misconnection into a star;The squirrel-cage rotor cage bar end sealing off,loose or break.2.2 after connect electric Machine can't start,have a hum.Possible reasons: not all plug in into single-phase starting;Motor overload;Being dragged mechanical stuck;Wound rotor motor rotor circuit broken into bolt;Inside the stator head end location wrong,or have a break,short circuit.Rated current of the motor.The motor rated current (A) is A "double motor power",namely "A kw two amps.tong Often refers to the commonly used 380 at about 0.8 v,the power factor of three-phase asynchronous motor ",the number will kw and double "is the rated current of the motor.For example: a model for Y112M - 4 three-phase motor fan asynchronous motor,the power rating of 4 kw,rated voltage of 380 v,so its rated current is about 8 a left and right sides.2.The experience formula of the motor rated current (A) = motor capacity X 2 (kW).The simplified formula and empirical formula is the use of the result is consistent,calculate the rated current and motor nameplate was very close to the actual current values,conform to the practical requirements.For example: "a Y132S1 -2 kW motor,using the simplified formula or empirical formula is the rated current of 5.5 x 2 = 11 a.Rated (three-phase ac asynchronous motor Current estimates and experience formula @ Li Enhua is < > in actual work,usually because of the damage and loss of the three-phase asynchronous motor nameplate,or the lack of practical maintenance electrician manuals and other data,can't know for sure the rated current of the motor.