Beijing Leader & Harvest Electric Technologies Co., Ltd.

Variable Frequency Drive

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HARSVERT- series of medium voltage VFD can usually be applied in these fields:
Power generation: induced draft fans, forced draft fans, condensate exhausting pump, boiler feed water pumps, primary fan, secondary fan, circulating pump, mill fan, slurry pump, mill .
Metals: dusting fans, slurry pump, feeding pump, furnace fans, compressor, mill
Cement: fan, discharge fan, waste gas fan, dust collecting fan, dust removing fan, mill.
Oil & Gas: water injection pump, oil transfer pumps, air compressor.
Mining: Fans, media pump, circulating pump, gas pump, oil separating pump, compressor, lift, mill, conveyer, hoisting machine.
Water: water supply pump, circulating pump.

Power Generation

1. Application of VFD In Power Plant
Frequency control is widely used in several fields for its superiority in energy-saving, adjustment precision, adjustment range and easy to communicate with automatic control system. This text is aiming to illustrate its broad prospects by introducing and concluding several success cases.

2. Medium voltage variable frequency drive application in Yunfu Power Plant
There are 4 sets of generators in power plant. Capacity of 1#, 2# units is 125MW. Capacity of 3#, 4# units is 135MW. Before reconstruction, 1# and 2# FD fans adopted damper adjusting, which caused much energy wasted.

3. MV VFD application in ID fan of Danhe Power Generation Co., Ltd.
The Harsvert-A Variable Frequency Drives are presented in the paper. The focus is on Series Connection Medium voltage Multi-level VFDs that are used in Danhe Generation Co.,Ltd. Variable Frequency Drives have a great of prospect in application because the drives can save a large mount of electric energy when they are used for fans.

4. Application of Medium-voltage VFD on condenser pump
This article focuses on the application of China-made cell-cascade multi-level medium-voltage frequency drive system in the Zhangshan Power Company on 2 # Unit Condensate water system, makes a comparison of energy saving before and after the reform. The results showed that the main auxiliary ...

5. Prospective development and application of MV VFD
Power generation plant is manufacturer of power as well as consumer of power. In structures of Chinese power generation plants, thermal power plants account for 70%. For general coal-fired generator units, plant itself consumes 4%~7% of its generating power and auxiliary equipments, such as big capacity fans and pumps, account for 80% ...


1. Medium voltage Variable Frequency Drive application in gas drainage system of coal mine
Annual production of Chongqing First Mine is 1500kt/a now. According to company plan, the production of raw coal is going to be up to 2400kt/a gradually. With increasing poduction and exploitation, gas rushing is more and more, which affects safety of production and development in mine. Draining gas by pump in goaf can control gas amount of coal face and air return system ...

2. Reform with Variable Frequency Drive in Xingcun Coal Mining
Install an impeller behind of another but rotating direction of impellers is opposite. We call this contra-rotating axial-flow fan. Two levels of impellers are contraposition and they are driven by same model motors. Watching from inlet, first level impeller rotates clockwise and the second level impeller rotates anticlockwise. Entering the first impeller ...

3. MV Variable Frequency Drive application in Xinyuliangshan Ore Mill
Xinyuliangshan Ore Mill locates in Jiangxi Province. It supplies ore to Xinyu Steel Plant. Ore mill added an ore dressing equipment. There were 3 same model pumps with isolation which were driven by high voltage motors. In normal operation, 2 pumps worked and the third was spare. If motor started in direct on line, big current would impact on grid ...

4. Reform with Variable Frequency Drive in contra-rotating axial-flow fan in mine
Contra-rotating axial-flow fan is backbone of breath system in mine. It works in 24 hours continuously. With digging and exploring extending, lane prolongs and air flow damand increases continuously. Fan power should increase. Air flow demand also requires to be adjusted due to seasons come and go. But power of motor and fan in coal mine is usually far more than ...

5. Variable Frequency Drive application in ID fan of flue gas purification system
In most middle/large mining companies, power consumption of motor accounts for 50% of total power consumption. LV Variable Frequency Drive is very common. But, defectiveness of MV variable frequency technology, and voltage withstand capacity of components have been restricting MV Variable Frequency Drive development and its application ...

6. HARSVERT-FVA series Variable Frequency Drive application in hoisting machine of coal mine
For long term, hoisting machine adopts rotor series resistance to adjust speed. It is low cost but with big torque, high consumption and complicated circuit. It damages contactor, resistor and electrical brush easily, which threatens system safety. With rapid development of power and motor technology, variable frequency technology can solve above problems.

7. Application of Medium-voltage Variable Frequency Drive in Large Medium Pumps for Heavy Medium Coal Selecting Technology
Coal selecting with heavy medium has been applied by coal processing enterprises more and more, because it needs less investment, and has short construction period, high washing and selecting depth, stable product quality and obvious economic benefits, etc. During the production, the speed regulating of the key equipment-medium pumps and the reasonable ...

Metallurgy Industry

1. Application of Variable Frequency Drive in #4 Duster Fan in Steel Plant
The steel works of Fujian Shangang Mingguang Co., Ltd. has three 15ton oxygen topblowing converters. During converting, a large quantity of brown-red smoke may exhaust from their mouthes. The high temperature smoke, which contains combustible gas and metal particles, must be cooled and cleaned, and then exhausted to chimneys for spreading or conveyed ...

2. Medium voltage Variable Frequency Drive system design in coal gas blast blower of coke oven
Tiantie Mental Refining Group Coking Plant has 2 sets of 58 model coking furnace, 1 set of JN43-80 coking furnace and related spare coal and gas as well as completed production system including purifying, chemical material collecting and sewage treatment system. The plant produces carbon coke 1120000t, coking coal gas 500 million m3 ...

3. Application of Medium Voltage Variable Frequency Drive in Henan Jiyuan Steel Company
Motor application is very widely in all industries. It is main power in enterprise and drives equipment, such as fan, milling and pump in metallurgy, oil, power and mining. Power consumption of medium voltage motor is enormous, accounting for 65~75%. In term of energy saving for motor, technology of variable frequency is the best way for speed adjustment, start-up and stop ...


1. Motor energy saving analysis in cement plant
Conventional speed adjustment has several modes. They are thyristor cascade control, DC adjustment, electric magnet sliding differential speed control, hydraulic coupling control, pole-changing control. They have disadvantages of low driving efficiency, difficult maintenance. But variable frequency control is stable and reliable with high precision and wide adjustment range.

2. Vector control VFD application in high-temperature fan
At present, competition is very intense. The key is cost. Power consumption of motor accounts for 30% of cost. Motor driving fan is a big part. So it is very important to reduce consumption of motor. Today, phenomenon of "large horse drives small dolly" is serious. If technology of variable frequency is adopted, it not only satisfies production requirement but also saves energy.

3. Application of Harsvert VFD in Zibo Cement Plant
Energy-saving Calculation:
Yearly work time: 11 months, month work time: 28 days. Total work time is 7392 hours.
For line 1:
Save power=(790-661)+(774-681)+(2221-1777)+(348-247)=767kW
Yearly save power=767×7392h=5669600kWh


1. Medium voltage VFD application in booster pump station
This is a new project with daily 160000t water output. Pump station is 1.2km away from intake of reservoir and 22km away from water plant. Transfer pipe is DN1200MM. Natural delivery ability is 100000t/d by advantage of topographic height difference and water level of reservoir. When delivery water is over 100000t/d, booster pump is needed.

2. Variable frequency drive design, operation in water purifying plant
Water plants began to use Variable Frequency Drive in 1984, such as Shengyang Water Plant, Haerbin Water Plant, Anshan Water Plant. Haerbin Water Plant uses ELEN drive made in Austria. Anshan Water Plant uses Siemens drive made in German. Jilin Second Water Plant and Third Plant use Leader & Harvest drive. We have introduced much information for Siemens drive before.

3. Medium voltage VFD application in Huludao Pingshan Waterworks
Huludao is serious short in water. Pingshan Water Plant is lifeblood of this city. Water-lack makes water adjustment very important. There are 4 sets of 10KV/710KW pumps with rated flow 1800m3/h and lift 120m. Pingshan Water Plant is 60km away from Huludao city and there are several hillsides of 100m on the way. So pipe pressure has reached to 0.9Mpa.

Oil, Gas

1. Medium voltage VFD application in centrifugal compressor
Mix gas from butanol and octanol workshop and ethene enter into synthesis reaction tower. Gas phase of propanal is created by the action of catalyst, after cooling, coarse propanal is created. Air returns synthesis reactor through compressor. Liquid phase propanal enters into rectifying tower and propanal product is output.

2. Medium voltage starter aplication in site
Qinghai Zhongxinguoan Technology Developing Co., Ltd is a manufacturer of fertilizer and chemical material. It locates in center of ChaidamuBasin. Producing/living power is provided by itself power plant. The power grid capacity is limited and can not stand big impact. Principle of spray drying tower is like this: air passes filter and heater ...

3. Application and Practice of Medium-voltage VFD in Water Injection System of Oilfield
Injecting water into oil beds through water injection wells is an important developing measure widely used for ensuring the oil bed pressure and increasing oil-extracting speed and extraction rate of oil storage. In the water injection works of oilfields, water-injecting pumps are the source equipment for water injection of oilfield and ensuring oil bed pressure ...

Synchronous Motor

1. Variable frequency operation of brushless synchronous motor
Abstract: because brushless synchronous motor does not part which may create spark, such as slip ring and carbon brush, it is used widely in site of explosive environment, such as chemical industry and coal mine. With idea of energy saving promoting, brushless synchronous motors need to reconstruct with variable frequency technology ...

2. Medium voltage VFD application on synchronous motor
Medium voltage synchronous motor is widely used as its characters of high power factor, stable speed and low speed simple design, such as fan, water pump, oil pump and so on. For big power low speed load, such as mill and compressor, using synchronous motor not only heightens power factor, but also leaves out variable-speed gear ...

3. Leader,Harvest VFD application on synchronous motor
According to characters of synchronous motor, we decide to adopt start mode of zero speed variable frequency with exciting current. During starting, exciting current selection is very important.
During operation of piston compressor, its torque pulsation is big and design speed is low. The less speed is, the more pole number of motor is. So electrical angle which is equavalent to space angle of stator and rotor is more ...

Variable Frequency Drive
  • A VFD HARSVERT-A series VFD is a masterpiece of outstanding performance and high reliability, which is widely used for the energy-saving application of the normal motors of fans, pumps ...
  • VA VFD Input current harmonic: <3% (comply with standard IEEE519);
    Input power factor: >0.95(>20% load);
    Output current harmonic: <2.5%; output DC ...
  • FVS VFD PWM rectifier technology. Energy can flow bi-directionally between power grid and the motor;
    Vector control for synchronous motor;
    Strong start up with load in ...
  • FVA VFD Auto re-start after the recovery of main medium voltage;
    Fly-start at any rotating speed;
    Bypass the faulty power cell automatically( OPTIONAL FUNCTION) ...