Three phase four wire system

 OEM industrial electric motors
Specifications
1. effiency: IE2 and IE1 
2. 20 years manufacturing experience 
3. 12 months guarantee 
4. low noise and vibtration
Three phase four wire system: phase voltage: phase line voltage between neutral and; Line voltage, phase ac electric motor and phase line voltage between two wire. Every relative phase voltage is the three-phase alternating current voltage and line voltage is three-phase alternating current (ac) and every two voltage; Like civil low-voltage electrical is 380 v, and every electric motor price two line voltage is 380 v, 3 phase voltage is present 380) = 220 v, people are generally single-phase 220 v electric, enterprises and use the low voltage power generally is 380 v three-phase electricity. Phase voltage: Ren Yixiang line and zero line in the Three phase motor three phase line voltage. Line of line voltage, three phase line to line voltage. Relationship: U = U line / 1.732. Two phase current: phase line and zero line load current. Line current, three-phase load between line and line current. Relationship: I = P/U/power factor, phase I line = P / 1.732 / U/power factor.

Sensorless brushless dc motor control - a back emf method

 AC induction cooling fan motor 
Specifications
1. Customised 
2. good quality 
3. 20 years manufacturing experience 
4. Altitude: ≤1000m

Assume that during the T T 1 0 ~ G5, G6 conduction, dangling a photograph, as shown in figure 1 (a), is a phase back emf ea = U an (a) phase voltage phase, a phase voltage U ag = U + U ng = an ea + U ng. At t0 time, ea = 0, b and c two phase current, on the other hand, and that the impedance is equal, and by the small diesel generator back emf waveform is known: the eb + ec = 0, so U ng = 1/2 U d, so U ag = ea + U ng = 1/2 U d. As long as it can detect or U an U d (U ag - 1/2) of the zero point, can be indirectly detect the zero moment of ea. Because the testing point ahead of the next converter 30 °, can be after 1/12 inverter cycle delay, shut off the G5, trigger conduction G1, which can ensure the maximum average electromagnetic torque motor can continuously produce. Repeat the above process, detection of ea in turn another zero and eb, ec all zero, and also delay, in turn trigger conduction of generator set spare parts a, b, c three-phase bridge arm up and down, to ensure the correctness of the permanent magnet brushless dc motor reversing sequence. According to different detection objects, and the detection method can respectively called phase voltage method (test U an), the terminal voltage method (U ag). 


 electric motor 20hp aluminum body 

Specifications
1. 20 years manufacturing experience 
2. competitive price,high quality 

3. Brand Name: FUJIAN DONGFENG MACHINERY ELECTRICAL LIABILITY CO., LTD

Among them, the terminal voltage method, the application of more. In terminal voltage method, in order to realize the phase voltage of zero crossing detection, first U ag, U can be the bg, U CG input low pass filtering devices, respectively, in order to eliminate the can seriously interfere with the back emf waveform, that there is no clear chopper signals passing zero [4]. And then use www.facebook.com/dongfeng.motor a voltage comparator, respectively each phase voltage compared to zero level, according to the comparison results of coding signal encoding, to get the rotor position signal. At present, the selection of zero level as shown in figure 2 [2], mostly by V, V b, V c three-phase symmetric star connection level V 0 instead of the center of the resistance of the circuit. Abroad recently put forward a new method: the three opposite electric potential (replace) with phase voltage first by square wave into a balanced three-phase sine wave, again through the star connection, get the central level, instead of a zero level. This method can get accurate "0" (zero after balanced three-phase sine wave synthesis), can reduce the position detection error.

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

Stator Motors Rotor 

Specifications
1. 20 years manufacturing experience 
2. competitive price,high quality 

3. Brand Name: FUJIAN DONGFENG MACHINERY ELECTRICAL LIABILITY CO., LTD

A 75 kw micro can WIN - G9 inverter commissioning the strange phenomenon Cause: a cement plant users to send a 75 kw can WIN - G9 frequency converter, the cause of the problem is, in the operation of the fire smoke in the inverter, the inverter downtime. Check, the power input circuit of the machine for three phase half controlled bridge, using the principle of controlled rectifier, on the main loop of the dc energy storage capacitor "soft power" and save the small power inverter commonly used rechargeable contactor. In fact half controlled bridge in this here is equivalent to non-contact soft blunt electricity switch. Inspection found that one of the thyristor module electrical motor 12v 1000w terminals have obvious signs of flashover arc burning, but the measurement is not short circuit. Found in the disassembly easily fixed nut landed, flashover reason seems to be a connecting screw loose, causing poor contact. The module for a combination of a diode and a one-way thyristor. And then check the control panel and inverter main circuit, without exception. The module, more than two phase half controlled bridge as the ac electric motor power input, after power on, with a small power 2.2 kW three-phase motor, feel no problem, switch to the new module after a same model, then to the site for installation. 


Y series totally enclosed protect Asynchronous motor
Specifications
1. 20 years manufacturing experience 
2. 12 months guarantee 
3. low noise and temperature rise 
4. high starting torque 

5. AC Voltage: 220V/380V, 380V/660V,400V/690V,220V/400V

Precaution, first will run to 5 hz frequency, frequency converter load as a fan, motor connector off first, make the motor no-load running. This trial run, got a fright! Frequency at 5 hz, no-load running current 45 a, although feel slightly larger, but consider for a possible repair, or frequency converter for motor winding parameters such as starting curve or torque compensation made adjustment caused by waiting for a reason, without notice. When up to 10 hz inverter panel shows the current and the output current is measured with clip-on table, have reached the 100 a! And the oscillation amplitude of the output current is great, but test the three-phase output voltage, about 70 v, balanced and stable. The motor cable release, electric logging on the inverter output, output frequency 10 hz, the output voltage is 70 v, 20 hz to 150 v, 35 hz to 250 v, after decreasing with frequency, to 50 hz, 400 v. In this process, the measurement of three-phase output voltage balance is very good. The inverter output of V/F curve electricalmotor1.blogspot.com accords with quadratic load torque characteristics. No problem. Output voltage balance and stability, and the output current is too large and the current volatility, obviously for the load caused by abnormal. This is lead to the conclusion of conventional judgment.

Brushless motor

Permanent magnet brushless motor is mainly composed of rotation (rotor) and three set of uniform distribution of the coil (stator), surrounded by a coil of the stator is fixed on the outside. Current flows through the coil magnetic field, three groups of overlay each other to form a magnetic field vector field. electric motor 12v 500w By respectively control the size of three groups on the coil current, we creates an arbitrary direction and magnitude of stator magnetic field. At the same time, through the attraction and repulsion between the stator and rotor magnetic field and torque can be controlled freely. For the arbitrary Angle of rotor and stator are an optimization of the magnetic field direction, can produce a maximum torque; Also, the stator can produce a magnetic generator set spare parts field direction of the torque output. Simply put, if the stator magnetic field generated and permanent magnet rotor magnetic field direction, motor will not output any moment. 

In this case, there are two magnetic field motor electric force of each other, but because of the force direction of rotation and the rotor, so the two magnetic field makes the bearing pressure, have not generated any rotary force. On the other hand, if the stator magnetic field direction orthogonal to the rotor magnetic field direction, it will wholesalemotor.blogspot.com generate a force to the rotor rotation, and this is also the location of the maximum torque. Any direction and size of the stator magnetic field can be divided into parallel and perpendicular to the two components of the rotor magnetic field direction. Such, mutually orthogonal magnetic field to produce rotary force, and parallel magnetic field is produced on the bearing pressure. For this reason, an efficient brushless motor driven function is to reduce the magnetic field of parallel to each other and to maximize the mutually orthogonal magnetic fields.

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

Creates a to synchronous speed n1 along the circle space inside the stator and rotor rotate clockwise rotating magnetic field.Due to the rotating magnetic field in the n1 speed rotation,the rotor conductor is still at the beginning of the rotor conductor will cut the stator rotating magnetic field and produce inductive electromotive force (judge the direction of the induced electromotive force with the right-hand rule) due to the rotor conductors sub is short circuit loop at each end,and  the effect of induction electromotive force,the rotor conductors will occur basic 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 (force in the direction of the left small electric motors hand rule determine) electromagnetic force on electromagnetic

torque,rotor shaft drive Motor vehicle 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-phase stator winding of the motor (the difference between a 120-degree Angle) to the balanced three-phase alternating current (ac),will happen in a rotating magnetic field,the rotating magnetic field cutting rotor winding,which occur in the rotor winding induced current (rotor winding is closed-cycle) rotor of current-carrying conductor in the stator rotating magnetic field under the action of electromagnetic force will occur,as to form the electromagnetic torque on the motor

shaft,motor rotation,and the motor rotation direction is the same as the rotating magnetic field

direction.

The rise of temperature of the motor and its related knowledge in electrical engineer to study

A summary of motor temperature rise and the temperature rise of the knowledge: Temperature rise is the motor and the environment temperature difference is caused by the electric heating. Run the motor iron core in alternating magnetic field can produce iron loss, winding can produce copper loss, after the power supply and other stray loss, etc. These will make the motor temperature perkins diesel generator rise. On the other hand motor will also heat dissipation. When heating and cooling is equal to equilibrium state, temperature no longer rises and stable on a level. When fever increase or reduce the heat will destroy the balance, make temperature continues to rise, enlarge the temperature, increased heat dissipation, at a higher temperature reaches a new equilibrium. But when the temperature difference of the temperature rise www.facebook.com/dongfeng.motor has increased than before, so that temperature is an important index in motor design and operation, marked the fever of the motor, in operation, such as the motor temperature rise suddenly increases, motor has a fault, or duct obstruction or load is too heavy. Factors such as temperature and temperature relationships: For the normal operation of the motor, in theory, under the rated load its temperature rise should have nothing to do with environment temperature, but the fact is still affected by the factors such as environmental temperature. When the temperature drops, the normal motor temperature rise will decrease slightly. 

This is because the winding resistance R, copper consumption reduced. Each drop 1 ℃, R down about 0.4%. To the cold machine, the ambient temperature increase 10 ℃, the ac synchronous motor temperature increased by 1.5 ~ 3 ℃. This is because the winding copper loss increases with temperature rise. So the temperature change of large influence on motor and closed. Every high air humidity 10%, due to the improvement of thermal conductivity, temperature rise can be reduced by 0.07 ~ 0.38 ℃, an average of 0.19 ℃. Elevation in 1 000 m for the standard, every litres of 100 m, the temperature rise of the temperature increase limit value of 1%. The maximum permissible limit working temperature and working temperature: Usually say that the class A limit working temperature is 105 ℃, A level of the highest working temperature is 90 ℃. So, limit working temperature and the maximum allowable working temperature difference? In fact, it is associated with measuring method, different measuring methods, it reflects the values, the meaning is different also. The thermometer method The measurement results reflect the local surface temperature of the winding insulation. This number, on average, than the actual maximum temperature winding insulation lower "the hot spot" of about 15 ℃. The most simple, the most widely used at the scene of the medium and small motor. Resistance method The measurement results reflect the average temperature of the winding wires. The number than the actual maximum temperature according to different insulation level lower 5 ~ 15 ℃. The method is to measure the conductor of the cold and hot resistance, according to the formula to calculate the average temperature rise. Embedment will copper or platinum resistance thermometer thermometer trial or thermocouples embedded in the winding and iron core or other need to measure the expected high temperature parts. The measurement results reflect the temperature of the temperature measuring element contact point. Large motor is often adopted to monitor the operating temperature of the machine. (see electrical engineer) measurement methods to measure the temperature and the actual maximum temperature have certain difference, so the insulation must be "limit working temperature minus the difference between" is "the highest working temperature".