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

 115/120 V AC Voltage and Three-phase Phase small 240v electric motor
Specifications
1.Specifications1.3-phase asynchronous motors 
2.IEC standard 
3.OEM 
4.Voltage:50HZ &60HZ;380V&415V 
5.Protection class: IP54 
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.

DONGFENG Brand Two Speed Motor
Specifications
1. DONGFENG Brand Two Speed Motor 
2. 3000RPM-750RPM 
3. Electrical motor 
4. factory price best quality 

5. 100% copper 
 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.

The use of the insulation resistance meter megohm meter method

motor Lamination ac motor blender parts 

Specifications
1. Lamination of electric motor 
2. IP54 class F 
3. 100% copper 
4. silicon steel stamping 

5.stunning performance 
Megohmmeter at work, its produce high voltage, the measured object is electrical equipment, so must be used correctly, otherwise it will cause personal and equipment accident. Before use, first of all, to do well the following preparation: (1) the measurement device under test must be before the power cut off, and the short circuit discharge, never promised to electric measuring equipment, to ensure the www.dongfeng-motor.com safety of person and equipment. (2) the possible induction of high voltage equipment, must eliminate this possibility, can be measured. Analyte (3) to clean surface, reduce the contact resistance, ensure the accuracy of measurement results. (4) to check whether megohmmeter before measuring the normal working state, the main check the "0" and "up" two points. The rocking handle, make the motor to achieve rated speed, when short 3 phase induction motor circuit by megger refers to the "0" position, should be to point to in the "up" position when open. (5) when used by Induction motor megger should be in a stable, strong place, permanent magnet motor and away from the big current conductor and external magnetic field.

Phase four trapezoidal wave type

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

Because of P - I controller gain and frequency response is limited, so the instability of the current loop control is easy to cause the current phase lag and control error. The higher the speed, the bigger the error. This also to the stability of the direction of the stator current vector not to follow the rotation of electric motor the rotor magnetic field and deviation in vertical direction effectively. This makes the motor output torque smaller, so we need more current to keep the motor torque. It is said the motor efficiency decreased. The higher the motor speed, this situation is worse. In some moods, the direction of single phase motor price motor current offset will reach more than 90 degrees, when the motor torque will be reduced to zero. In the case of using wave type commutation, if speed is higher than the state, electricity output negative moment, but it is impossible to happen. 


Y series best cast iron three phase induction 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

Wave type control mode with the nature of the problems, it is the current of motor control is a control variable. When the motor speed continuously improve, P - I controller reaches the limit bandwidth, this control mode will lose its effect. Vector control can solve this problem, it is directly controlled by corresponding to the rotor magnetic field parallel and perpendicular to the direction vector current component to achieve precise control of the stator coil current. Theoretically, the vector current can be decomposed into two parallel and perpendicular to the rotor magnetic field small diesel generator current component. Because the current in the two directions is static, so P - I controller to control the current of can is dc, rather than string wave signal. So the coil current and voltage of the controller output is a constant, not the original variables changing with time, it also eliminates the controller on the frequency response and phase drift limits. If using vector control method to control the brushless motor, the quality of the current control and motor www.dongfeng- motor.com speed has nothing to do.

Dc braking principle

Dc braking principle. When asynchronous motor stator winding zhongtong into direct current, the magnetic field generated by the constant magnetic field will be the space www.facebook.com/guohong.trading position unchanged, and the speed of the rotor because of its inertia continues with its original spin, at this point, the rotation of the rotor cutting the static magnetic field and produce brake torque, system stored kinetic energy is ac motor converted into electrical energy consumption in the rotor circuit of the motor, thus to achieve the effect of fast brake motor. In order to guarantee the safety of the motor, dc brake is best used with braking energy. Inverter dc brake setting, dc fan motor brake basically set the following three contents 2.1, started to dc brake starting frequency 2.2, applied to the stator winding voltage dc brake. As a result of the stator winding dc resistance is very small, so lamination the dc brake voltage adjusting range is usually the circuit dc voltage of the 0 ~ 10%; 2.3, the braking time. Braking time impossible and actual braking time coincide, in order to ensure the braking effect, usually set slightly larger;

The application of squirrel-cage asynchronous motor soft starter - working principle of the soft starter

Soft starter is a collection of soft start,soft stop,light load energy saving motor parts and multi-functional protection of motor control device.It not only realize no impact in the whole process of starting and smooth starting current,and according to the characteristics of the motor load to adjust the parameters in the process of starting,such as current limiting value,starting time,etc.In addition,it also has the protection of motor function,that is fundamentally solves the disadvantages of traditional step-down starting equipment.Soft starter used three opposite parallel thyristor as a voltage regulator,to wear it while plugged motor run capacitor into a power supply and the motor stator.

This circuit such as three-phase fully-controlled bridge rectifier circuit,main circuit diagram as shown in figure 1.When using the soft starter motor,the output of the thyristor voltage increase gradually,motor speed gradually,until the thyristor conduction,all motor electricalmotor1.blogspot.com working in the rated voltage on the mechanical properties of smooth start,reduce the starting current,avoid start over-current trip.For motor to achieve rated speed,the end of the boot process,the soft starter automatic bypass contactor to replace has completed the task of thyristor,provide the rated voltage for the motor magnet motor operation,to reduce the heat loss of thyristor,prolong the service life of the soft starter,improve the work efficiency,and make the power grid to avoid the harmonic pollution.Soft starter and also provide function of soft parking,soft parking,in contrast to the soft start process,voltage decreases gradually,speed gradually decreases to zero,to avoid the free parking torque caused by the impact.

Electric welding machine before use should be paid attention to what issues?

Electric welding machine of new or unused for a long time,often due to be single phase generator affected with damp be affected with damp between winding,winding and reduce insulation electric fan motor resistance between the casing and likely to occur at the beginning of the use of short circuit and grounding,equipment and personal accident. So before using shaking table to check whether the insulation resistance of qualified application.Before starting a new welder,should check electrical system contactor parts are in good condition,think after normal,may be started under no-load test run. IE2/IE3 electric motor Prove that no electrical hazards,after the load cases,finally can run normally.Dc arc welding machine should be wholesalemotor.blogspot.com in accordance with the direction of rotation,attention should be paid to the fan with the ventilator on direction of rotation is correct,blown out by the above should be used. In order to achieve the purpose of cooling welder.

The category of dc regulated power supply and choose

Dc stable power supply according to the habit can be divided into chemical power supply,linear

regulated power supply stability and switch mode power supply,they respectively have different types:Chemical power source,we used ordinary dry-cell batteries,lead-acid batteries,nickel cadmium,nickel metal hydride,lithium ion batteries are belong to this category,each have their advantages and disadvantages.With the single phase asynchronous motordevelopment of science and technology,and the intelligent battery;In rechargeable battery materials,American researchers found that manganese a iodide,use it can produce cheap,small,discharge time is long,many times after charging still maintain good performance and environmentally friendly rechargeable batteries.Linear stable power supply,linear regulated power supply is a common feature is that it is power device adjusting pipe work in the linear area,stable output by adjust the voltage drop between the tube.

Due to adjust the tube static loss is big,need to install a large radiator to electric motors 12

voltheat it.And because the transformer work in power frequency (50 hz),so the weight

is bigger.This kind of power source advantage is high stability,small ripple,high reliability,easy to make it more road,continuous adjustable output of finished products.The disadvantage is that large volume,heavy,efficiency is relatively low.Such a stable power supply and there are 5kw permanent magnet generator many,from the output properties can be divided into www.dongfeng-motor.com regulated power supply and current regulator and voltage regulator,steady into voltage steady flow (bistable) power supply.From the point of the output value can be divided into fixed point switch to adjust output power,band and several continuous adjustable potentiometer.From the output indicator can be divided into pointer on type and digital display type and so on.

The shaded pole motor

Usually see single-phase motor are shaded pole motor,generally used in small devices start torque,such as electric fans and other small household electrical appliances.In this kind of motor,small single stage rotary concealed copper coils can produce a rotating magnetic field.Each

pole is surrounded by diesel generating copper coils or copper tape on part of the living;In order to prevent the current in the coil change (lenz's law) can produce induced current in the copper strip,so that every cycle maximum field strength across the surface,to produce a large enough lower rotating magnetic field to drive the rotor and the load on it.As the rotor increase its torque to the largest,the original (fixed) by turning the magnetic field will rotate with the rotation of the rotor.It is

difficult to reverse the motor unless internal structure change.Another common single-phase ac motor is the split-phase induction motor,such as washing machine and dryer is typically used for large household appliances.Compared with the electricalmotor1.blogspot.com shaded pole

motor,these motors can be started by winding and centrifugal switch connected together can often

provide a big start torque.In the split-phase motor,the design of the startup winding resistance than

the running winding resistance.This will generate a LR circuit,the circuit will slightly change the

phase of the current in the startup winding.When the motor is started,the start winding through a set of the above pressure with no rotation of the centrifugal switch spring connection on the power

supply.Winding start winding line is thin and less than used in the main winding line several

times,so it is a high resistance and low inductance.Low inductance and resistance rate produces a

small phase shift does not exceed 30 degrees,the phase shift is determined by the main winding

magnetic field lines and determined by the startup winding pumps magnetic field lines.Can run by changing the startup winding and winding connection to easily change the direction of rotation is

started.Start winding magnetic field phase as the grid phase changes,to produce a start the motor

rotating magnetic field.Once the motor reaches near design operating speed,the centrifugal switch

start action,shut off the connection between the startup winding to the power grid.Motor running by

running winding.Start winding must be disconnected,because it will increase the loss of the motor.