Two single polar stepper motor

This kind of stepper motor is referred to as the single polarity because each winding current to flow along one direction only.It is also referred to as the two line stepper motor,because it only contains two coils.The reverse polarity,two coil winding on the same core,with the same intermediate tap.Single polar stepper motor also referred to as 4 phase stepper motor,because it has four excitation winding.Single polarity of stepper motor fuses have 5 or 6.If the leads of the stepper motor is 5 root,then one of them is connected to the public line f v +),the other four phase 4 root respectively connected electricalmotor1.blogspot.com to the motor.If the leads of the stepper motor is 6,so it is more sections of a unipolar stepper motor has two windings,each winding have asked tap in a lead.But how to distinguish the lead? Please continue to read the following content.Distinguish line 6 single polar stepper motor joint recycling old printer when most often encounter this type of unipolar stepper motor.

Line 6 single polar stepper motor usually permanent magnet generators for sale looks like two single sections of stacked together,each single section has three lines elicit f see figure 6).This is a very easy to distinguish the leads of the stepper motor.Distinguish between 6 line stepper motor fuses order work is quite simple.If it is the structure of many sections of stepper motor,then the order of the lead has actually been given,with the digital multimeter can identify each public line of winding.Just keep winding for two fuses corresponding ac electric motors consistent,it doesn't matter whether they order only affects the direction of rotation of motor.If not more 3 phase motor sections of six lines of stepper
motor,can press the following steps to determine winding lead: (1) using a digital multimeter find public side each pair of windings.(2) according to the above methods can find two winding,separating them and marked.Please send one winding of marked A and C (also can be l and 3),another tag for B and D (can also be A 2 and 4).In each pair of windings,which fuses what order is not important,as long as
the pair is enough.

Output voltage space vector method

In direct torque control,if we can get any phase of space voltage vector,will help to reduce the

torque ripple under low-speed,reach the steady state performance of vector control at low speeds.In the third quarter no beat control can get any phase of space voltage vector,but calculation is more complex,more difficult.Another for any phase of space voltage vector method is to use PI regulator.A.b.induction motor salesPlunkett direct torque and flux adjustment method is A kind of PI adjustment method,only then had not space voltage vector this concept,can only use the method of SPWM output voltage motor control.In the literature,the proposed method of direct torque control using PI control,and output space voltage vector for the SVM method. Obtained by torque and torque feedback given error input torque PI controller,PI adjustment get q axis acmotortrading.blogspot.com voltage vector and stator flux and stator flux feedback given by the gain of the stator flux linkage error input PI regulator,PI regulation to obtain d shaft voltage vector,then d axis and q axis voltage vector rotation transform the alpha shaft under the static coordinate system and beta,used for the output of the space voltage vector,clearly the space voltage vector in the phase space position is arbitrary.

Structurally similar direct torque control based on PI control on the stator flux vector control,but there is a difference between the two,the stator flux vector control based on synchronous rotating coordinate system,the stator flux orientation in d axis,q axis flux is zero in the d axis direction and the flux and q axis direction of current decouple,and these for direct torque control based on PI control does not need to,among them only need to make the output torque and stator flux feedback can be given by PI regulating method to follow,so from the implementation is relatively simple,robustness is also good at the same time,and compared with the traditional gasoline generator spare parts direct torque control can improve the switching frequency,reduced torque ripple under low-speed,but in this method need to select the right PI parameters,otherwise it will affect the control system dynamic and static performance.In addition to the above this kind of PI control of direct torque control,also in the literature in a.b.Plunkeet direct torque and flux control method on the basis of further research,the use of space voltage vector way output,not detailed here.

Three-phase motor open phase protection and current changes

Its working principle: Combination switch Q closed first, prepare for motor starting. The main circuit and control circuit and electricity, connect to A, C and two ac contactor coil KM2 electricity, iron core is sucked, concatenated in ac contactor KM1 normally open contacts closed KM2. When press the starting button SB2, ac contactor KM1 electric suction, main circuit of the three main contact closure, auxiliary contact since locking, starting motor M. When there is lack of phase motor, if the lack of A phase or C phase, ac contactor coil KM2, losing electricity concatenated in ac contactor coil KM1 contact KM2 disconnect, make the ac contactor coil KM1 lost electricity, so the lock off contact, the contact is disconnected, the motor can't start losing electricity (right now) or stop; If lack of phase B, ac contactor coil KM1 losing electricity, the lock off contact, main contact disconnect, motor power, can't start (right now) or stop the operation. Thus ensure the motor in diesel generating set the circuit of phase is not 8500w gasoline generator destroyed.

Star delta start

The principle Learn the electrician will not star triangle how line. 1. When the load on the motor has no strict requirements and to limit the start torque motor starting electric fan motor parts current and motor can use 380 v/Δ connection condition star triangle boot method; 2. The method is: in the motor when the motor first starts, connect into the star connection, when the motor start again after successful will convert into triangular connection (via double-throw switch switch); 3. Because of the motor starting current is proportional to the power supply voltage, the power grid provided by the starting current is only 1/3 of the full voltage start current, but also start torque only 1/3 of the full voltage start torque. 4. Star triangle start, step-down starting at the expense of his power in exchange for a lower cost of starting current. So it defies and with the size of the motor power to determine whether to need to use the star triangle start, also depends on what kind of load, the general load when need to start the runtime negative light load can be used star triangle start, usually a squirrel-cage motor starting current is 5 to 7 times that of the running current, and voltage requirements for power grid is usually plus or minus 10%, in order not to form the impact to power grid voltage is too large to adopt star triangle start, general requirements in squirrel-cage motor power by more than 10% of the rated power transformer will be will use the star triangle. 5. 

In the process of actual use, found to be the star triangle step-down starting motor starting electricalmotor1.blogspot.com 11 kw are needed, such as fan, 11 kw electric current when it starts at about 7-9 times (100) A, according to the normal configuration of the thermal relay can't start, it's no use (the draft) thermal relay with big and does protect the motor, so suggest using step-down start. Two conditions 1, the capacity of 7.5 KW three-phase asynchronous motor. 2, motor in starting the instant power grid voltage fluctuation is less than 10%, for not often start the motor can be up to 15%; If there are special transformer S transformer or 5 p motor, motor asynchronous motor allows direct frequently. 3, meet the experience formula: Ist/IN < 0.75 + ST \ 4 pn ST - public transformer capacity, KVA; PN - motor rated power, KW; Ist / - IN the ratio of the motor starting current and the rated current. 4, star triangle step-down starting motor three-phase winding six external terminal: A - X, Y and C - B - Z (hereinafter with rated voltage 380 v motor as an example) A. start star: X - Y - Z, A, B, C three termination three-phase ac voltage 380 v, the voltage of each phase winding, 220, A 380 v directly start current is greatly reduced, to avoid the excessive starting current impact on grid form. At this time of the torque are relatively small, but the motor can reach a certain speed. B. angular run: star start the motor for a period of time (about) a few seconds after reaching a certain speed, electric switch connect six terminals into a triangle, and again from 380 v power supply when each phase winding voltage of 380 v, torque and rotational speed is greatly increased, the operation process of motor in the rated conditions.