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- Liquid Resistance Speed Control Cabinet: Efficient and Smooth Motor Speed Control Solution
fluidsResistance speed control cabinet: Efficient and smooth motor speed control solutions
In the field of industrial motor control, liquid resistance speed control cabinet has become the ideal choice for speed control and soft starting of large and medium-sized wire-wound asynchronous motors with its unique technical advantages and reliable performance.
Liquid resistance speed control cabinet (also known as liquid resistance)starter cabinet(or water resistance cabinet) is a type of water resistance cabinet that employsaqueous electrolyte solutionSpeed control devices as conductive media. It is realized by changing the resistance value of the liquid resistor strung in the rotor circuit of the motor.Large and medium winding asynchronous motorsSoft start and speed controlWidely used inBuilding materials, metallurgy, mining, petroleum, chemical industryand other industrial sectors。

I. Working principle and technical characteristics
1. Intelligent working principle
The liquid resistance speed control cabinet is based onPrinciple of conductivity of aqueous electrolyte solutions(of a machine) operate. The resistance between the two electrodes is changed by varying the distance between the two electrodes in the aqueous electrolyte solution, or by adjusting the concentration of the electrolyte solution。
For fan and pump loads, the unit is designed according to theThe relationship between P ∝ n³(P is the output shaft power, n is the rotational speed), by changing the resistance value of the liquid resistance strung on the motor rotor to change the motor speed, so as to achieve the purpose of speed regulation, energy saving. For motors used in rolling mills in the metallurgical industry, by changing the resistance value of the liquid resistor, it can effectivelySuppresses the inrush current of the motor at the moment of the start of zappingThe purpose is to protect the motor.。
2. Technical excellence features
- Smooth stepless speed regulation: Smooth starting of the main motor by changing the concentration of the solution or by steplessly adjusting the resistance value within the range.
- Large thermal capacity design: Liquid resistors have a large thermal capacity and can be started continuously for 5 to 10 times.
- Low starting current: The ratio of starting current to rated current is satisfactory at ≤1.3.Small starting current: Iq≤1.3Ie (A)
- Low voltage starting capability: Smooth starting when the grid voltage is lower than 10% of the motor's rated voltage.
- Rugged constructionResistance box adopts high-temperature resistant material, which can withstand high temperature of 160℃ without deformation, and its service life can reach more than 20 years.
II. Core structure and component design
Liquid resistance speed control cabinet mainly consists ofLiquid Variable Resistors, Plate Type High Efficiency Heat Exchangers and Electronic Control Systemsmake up。
1. Cabinet structure
The cabinet frame consists ofProfile WeldingThe internal and external surfaces are made ofspray-plasticizedThe product is highly resistant to heat and humidity, and corrosion.The Protection class up toIP20 or IP30It can also be customized with higher protection level according to the requirements. Cabinet design is reasonable, firm, beautiful, and has good sealing and dustproof performance.。
2. Conducting electrodes
Conductive plates (including dynamic and static plates) are made ofRare metal plating on the surface of purple copper platetechnology, with non-oxidizing, non-corrosive, maintenance-free characteristics, to achieve the purpose of long-term reliable use. The poles are insulated from each other by means of an insulating device to ensure the safe operation of the equipment.。
3. Liquid resistance systems
Liquid resistance box usingpolymer polytetrafluoroethyleneWelding of high-temperature-resistant plastic sheets. The box is equipped with an electronic device made ofSodium carbonate aqueous solutionComposition of the electrolyteIt has good electrical conductivity and heat capacity. Each tank is fixed with static pole plate at the bottom, and the static pole plate leads to the terminal using high-voltage heat-shrinkable insulating sleeve, which ensures reliable insulation between the poles.。
4. Electrical control systems
The electrical control part is centrally placed in the electrical control unit box inside the cabinet to realize theControl, multiple protections, display of operating conditions, and operating and actuating functions. Optional Configurationhuman-machine interface (HMI) systemsIt realizes remote monitoring and operation with human-machine dialogue function, simple operation and high reliability.。
Third, the performance characteristics and advantages
1. Energy efficient performance
Liquid resistance speed control cabinet in the fan, pump load applications, operating power saving rate up to10-30%. Through smooth starting and speed control, it can significantlyReduced energy consumption, improve the efficiency of equipment operation.
2. Excellent starting performance
- Smooth startingNo mechanical stress on the equipment, which can prolong the life of mechanical equipment and motors.
- Low starting current: Starting current less than 1.3 times the rated motor current
- High starting success rate: Unaffected by grid voltage fluctuations and load variations, ensuring a successful start.
3. Reliable protection functions
The device hasMultiple protection functions such as start-up timeout, overpressure, over-travel, over-temperature, etc.to ensure the safe operation of the equipment under various operating conditions. To the power gridno harmonic pollutionHigh power factor, mill type load COS¢ can be increased by 0.18 to 0.22 (compared with series reactor).。
IV. Application areas and scenarios
Liquid resistance speed control cabinets are widely used in the following areas:
1. Heavy industry
- Building materials industry: Cement plant ball mills, crushers, fans and other equipment
- Metallurgical industry: Equipment such as mills, compressors, fans, etc.
- Mining industry: Elevators, crushers, conveyors and other heavy equipment
2. Energy and infrastructure industries
- petrochemicals: Various types of pumps, compressors and other equipment
- Power industry: Boiler feed pumps, supply fans, induced draft fans and other auxiliary equipment
3. Range of applicable motors
Liquid resistance speed control cabinet is suitable for rated voltage380V-10kVThe power ranges from75kW to 10,000kWThe heavy load smooth soft start of wound asynchronous motors in all industries, especially suitable forLarge inertia loads和Heavy duty startingsituation。
V. Technical parameters and specifications
Main technical parameters
VI. Selection and Installation Guide
1. Selection considerations
When selecting a liquid resistance speed control cabinet, users are required to provide the following technical information:
- Main parameters of the main motor:Rated power, stator voltage/current, rotor voltage/current等
- Load Characteristics: Load type (fans, pumps, mills, etc.),inertia (mechanics)
- Use of environmental conditions: ambient temperature, humidity, altitude, etc.
- Special function requirements: whether remote monitoring, automatic control and other functions are required
2. Installation environmental requirements
In order to ensure the normal operation of the liquid resistance speed control cabinet, the installation environment should meet the following requirements:
- environmental temperature: -40℃~+50℃
- Relative air humidityNot to exceed 90%
- altitudeNot exceeding 2000m (special design can be made according to specific working conditions if the altitude is above 2000m)
- slopeNot more than 5°
- installation locationNo fire, explosion hazards, chemical corrosion or strenuous exercise
VII. Maintenance and Troubleshooting
The maintenance of the liquid resistance speed control cabinet is relatively simple and focuses on the following aspects:
1. Periodic inspection and maintenance
- Electrolyte examination: Regularly check fluid levels and electrolyte concentrations to ensure they are within normal limits
- Polar Plate Inspection: Check pole plates for corrosion or scale buildup and clean if necessary
- Insulation Testing: Regular testing of insulation resistance to ensure safe operation of equipment
2. Common Troubleshooting
- Abnormal resistance value: It is possible that the electrolyte concentration is not correct or the pole plate is not positioned correctly.
- overheating: Check that the cooling system is working properly and that the ambient temperature is not too high
- Reduced starting performance: Check whether the electrolyte needs to be replaced or adjusted
Liquid resistance speed control cabinet with itsSmooth starting characteristics、Reliable operational performance和Significant energy savingsThe newest version of the product has been developed for the control of large and medium-sized wire-wound asynchronous motors. ItsSimple structure and easy maintenanceThe characteristics of theBuilding materials, metallurgy, mining, petroleum, chemical industryWidely used in industrial sectors such as。
With the continuous development of industrial technology, liquid resistance speed control cabinets will continue to be used in theIndustrial energy saving and automation controlThe field plays an important role in creating greater economic benefits for users.





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