Quality Vector VFD & Servo VFD factory

Since 2011, Ceramic Factory --Modena has harnessed the power of ZFENG’s cutting-edge industrial automation solutions, featuring 24 ball mill energy-saving cabinets equipped with Variable Frequency Drives (VFDs) and 12 plunger pumps integrated with servo drives and soft starters. These robust systems have delivered 14 years of continuous, trouble-free operation, significantly reducing energy consumption, minimizing maintenance expenses, and ensuring seamless ceramic production. This enduring success highlights ZFENG’s dedication to delivering durable, high-performance motor control technologies tailored to industrial excellence.

ZFENG Global Distributor Recruitment Join Hands with ZFENG, Scale New Heights in Global Industrial Automation! Guangdong ZhuFeng Electric Co., Ltd., a leading enterprise in China’s industrial automation sector, is now inviting qualified distributors worldwide to collaborate in expanding international markets and jointly driving the industrial energy efficiency revolution! About UsZhuFeng Electric, headquartered in Guangdong Province—the heartland of China’s manufacturing industry—has been deeply engaged in industrial automation for nearly two decades. The company specializes in the research, development, production, and sales of core products such as variable frequency drives (VFDs), soft starters, and intelligent motor control systems. Our solutions are widely applied across manufacturing, energy, infrastructure, and other sectors, with a global footprint spanning over 50 countries and regions. Driven by technological innovation, we possess multiple independently developed core technologies and boast internationally certified products renowned for their exceptional quality and stable performance. Committed to delivering comprehensive solutions and excellent service, we have earned the trust and praise of customers worldwide. Global Distributor Recruitment: Seize Growth Opportunities TogetherTo further deepen our global market presence and enhance brand influence, ZhuFeng Electric is now launching a global recruitment drive for high-caliber distributors. We eagerly anticipate partnering with you to explore the following markets: Southeast Asia: A burgeoning market with boundless potential, sharing in the dividends of industrial automation upgrades. Middle East: Rich in energy resources and thriving with infrastructure projects, jointly pioneering new frontiers in smart energy. Africa: Rapidly developing with robust demand, collaborating to empower Africa’s industrial rise. Latin America: A vast market brimming with opportunities, creating a new chapter in Latin America’s industrial automation journey. What We Seek in a Distributor Extensive industry experience and a mature sales network in industrial automation, electrical equipment, or renewable energy sectors. Strong market development capabilities and customer service expertise, capable of providing localized sales, technical training, and after-sales support. Alignment with ZhuFeng Electric’s brand philosophy and corporate culture, dedicated to establishing a long-term, stable partnership for global market expansion. Benefits of Becoming an Everest Electric Distributor Premium Products: Gain exclusive distribution rights to ZhuFeng Electric’s full range of high-quality, high-performance products. Technical Support: Receive professional technical training and ongoing support to facilitate market penetration. Marketing Assistance: Access a wealth of marketing resources and promotional support to elevate your brand visibility and market share. Service Backing: Benefit from ZhuFeng Electric’s comprehensive after-sales service system, ensuring worry-free customer support. Lucrative Returns: Share in market opportunities and enjoy competitive profit margins alongside sustainable, long-term rewards. How to ApplyInterested applicants are invited to submit their applications through the following channels: Email Application: Send your company profile, market coverage details, and a brief proposal outlining strategic alignment with ZhuFeng Electric to: xhr_gz@powerton.com.cn. Please indicate “Global Distributor Application” in the email subject line.

The grand opening of the 2025 Indonesia Industrial Exhibition! China Indonesia industrial cooperation sets off a new wave! Exhibition time: June 4-7, 2025 Venue: Jakarta International Exhibition Center Site:HALL A2D210 We warmly received all the purchasing buyers and patiently answered their questions. In our communication with customers, we explored their needs through listening and directly communicated with them, which is more authentic than any research! The exhibition is not the end, but the starting point - the needs collected and connections established will continue to ferment in the future. Exhibiting is like a marathon. Preparation before the exhibition is a long training, execution during the exhibition is a sprint, and follow-up after the exhibition is a continuous endurance. But the real gain lies not in how many orders we sign, but in the fact that through this' practical exercise ', we understand the market, customers, and ourselves better. The Indonesia Industrial Exhibition is still in full swing, and we welcome visiting customers to come and have in-depth discussions with us at any time. At the next exhibition, we will not only bring better products, but also the accumulated wisdom to continue writing the story of Made in China on the world stage.

Dear Friends and Industry Partners, We are thrilled to invite you to join Guangdong ZFENG Electric Co., Ltd. at the International Industrial Week 2025! As a verified supplier, we’ll be showcasing our cutting-edge products, including the ZF-D200 Series and ZF900 High-Performance Frequency Inverters, at Booth No. A2D210. Event Details:Date: June 4-7, 2025Venue: Jakarta International Expo (JIE), IndonesiaBooth: A2D210 Discover innovative solutions for applications from 0.4kW to 800kW, featuring advanced EtherCAT compatibility and precision control. Whether you’re interested in OEM/ODM partnerships or exploring our latest technology, this is the perfect opportunity to connect! Scan the QR code below to register for a free ticket or explore more about our products. We look forward to meeting you and discussing how we can power your success together!

 ZFENG is thrilled to announce a landmark partnership with a leading agent in Bangladesh, marking a significant step in expanding our global footprint. This strategic collaboration appoints our trusted partner as the official agent to distribute and promote both ZFENG and ACI brand products across the vibrant Bangladeshi market.  The partnership leverages the agent’s deep market expertise and extensive distribution network to bring ZFENG’s innovative products alongside ACI’s trusted consumer goods to Bangladeshi consumers. This move aligns with ZFENG’s commitment to delivering high-quality, sustainable solutions tailored to local needs while strengthening ACI’s established reputation in the region.  “We are excited to join forces with our Bangladeshi partner to introduce ZFENG and ACI products to a dynamic and growing market,” said a ZFENG spokesperson. “This collaboration reflects our shared vision of innovation, quality, and customer satisfaction, and we look forward to making a positive impact in Bangladesh.”  The agreement is set to enhance product accessibility, offering Bangladeshi consumers a diverse range of solutions, from ZFENG’s cutting-edge offerings to ACI’s well-known consumer brands. This partnership underscores our dedication to fostering economic growth and delivering value to communities in Bangladesh. Stay tuned for more updates as we continue to expand our global reach and bring exceptional products to new markets.

I. Application Scenarios and Technical Implementation 1. Freezing Water Circulation System Principle: The frequency converter regulates the speed of the chilled pump based on the return water temperature to adjust the flow rate and achieve indoor temperature stability. Technical Details: Flow Rate and Speed Relationship: The flow rate (Q) is proportional to the first power of the speed (n), and the shaft power (P) is proportional to the third power of the speed. For example, when the flow rate is reduced to 80%, the shaft power is reduced to 51.2%. Control Strategy: PID control is adopted, combined with return water temperature feedback, to dynamically adjust the pump speed and avoid freezing of the evaporator, ensuring system safety. Case: A certain type of frequency converter is applied in the HVAC water circulation system to achieve stable outlet temperature of chilled water, with an energy - saving effect of 20% - 40%. 2. Cooling Water Circulation System Principle: Taking the temperature difference between inlet and outlet water as the control basis, the speed of the cooling pump is adjusted to optimize the cooling efficiency. Technical Details: Temperature Difference Control: When the temperature difference is large, the pump speed is increased; when the temperature difference is small, the pump speed is decreased to keep the condenser working efficiently. Protection Requirements: The cooling tower environment is humid and dusty, so the frequency converter needs to have an IP55 protection level to prevent the entry of water vapor and dust. Case: A certain industry - leading product drives the cooling tower fan in a commercial building, achieving 30% energy savings through constant temperature difference control and integrating intelligent modules for remote monitoring. 3. Cooling Tower Fan Control Principle: Adjust the fan speed according to seasonal changes and cooperate with the cooling pump to achieve the best energy - saving effect. Technical Details: Smooth Start - Stop: The frequency converter reduces mechanical shock and extends the fan life. For example, a certain type of frequency converter is applied in the cooling tower fan, and a lower - limit frequency is set to avoid damage to the gearbox. Energy - saving Effect: When the fan runs at a low speed, the amount of drift water is reduced, the water source is saved, and the noise is reduced. Case: The frequency converter controls the cooling tower fan in the building of a certain transmission company, achieving 50% energy savings and realizing automatic management through the BMS system. 4. Ventilation System Principle: In scenes such as subways and industrial plants, the frequency converter drives the fan system to adapt to complex environments (such as high temperature, high humidity, and high dust). Technical Details: Protection Level: The subway ventilation system needs an IP55 or higher protection level to ensure stable operation of the equipment in harsh environments. Intelligent Control: Integrated PLC monitoring is used to adjust the air volume in real - time. For example, a certain type of frequency converter supports multi - pump variable frequency start in the subway project, reducing the pressure impact on the pipe network. Case: A certain city subway project adopts a frequency converter, and through the functions of condensation and frost protection, the reliability of the ventilation system is ensured. II. Energy - saving Effect and Data Support 1. Significant Energy Savings Theoretical Basis: The shaft power is inversely proportional to the third power of the speed. When the flow rate is reduced by 20%, the shaft power is reduced by 51.2%. Actual Cases: A Certain Transmission Company Building: After using the frequency converter, the HVAC system saves about 50% of energy, and the annual electricity cost savings are significant. A University Hospital: The frequency converter saves 800,000 kilowatt - hours of energy annually, reduces 750 tons of carbon dioxide emissions, and the COP is increased to 3.6 (heat pump) and 5 (cooling machine). A Certain Type of Frequency Converter: It saves 20% - 40% of energy in the HVAC system and avoids the energy consumption of full - speed operation through dynamic speed regulation. 2. Extended Equipment Life Soft Start: The frequency converter reduces the starting current impact of the motor and extends the life of pumps and fans. For example, the maintenance cost of equipment in a certain project is reduced by 30% due to smooth starting. Mechanical Protection: The cooling tower fan sets a lower - limit frequency through the frequency converter to avoid damage to the gearbox due to low - speed operation. 3. Environmental Adaptability IP55 Protection Level: In HVAC environments with a lot of dust and moisture (such as food processing plants and coal mines), the frequency converter needs to reach an IP55 level to prevent the entry of dust and water vapor and ensure stable operation. Case: A certain type of IP55 frequency converter is applied in high - requirement occasions such as military units and weapon manufacturing, adapting to harsh industrial environments. III. Intelligent Integration and System Integration 1. Integration with Building Automation System (BAS) Communication Protocols: The frequency converter supports protocols such as Modbus and Profibus, and can be seamlessly connected with BAS to realize remote monitoring and parameter adjustment. Case: A certain type of frequency converter uses an intelligent connection module, and mobile devices can be used for quick commissioning and monitoring, improving the intelligence level of the system. 2. Data Monitoring and Analysis Real - time Data: The PLC monitoring system records equipment efficiency, such as the number of cooling machine operations and automatic load adjustment, to ensure the optimal state. Fault Warning: The frequency converter stores fault information, such as flexible handling when signals are missing, reducing downtime. 3. Energy Management Dynamic Adjustment: Automatically switch the operating mode according to the season and time period. For example, switch to the energy - saving state at night and on weekends, and keep running at a low speed to maintain temperature and humidity. Case: The BMS system of a certain building automatically adjusts the frequency converter parameters in winter and summer to meet the demand and save energy at the same time.   Conclusion The frequency converter realizes the following core advantages in the HVAC system through precise speed regulation, intelligent control, and efficient energy management: Significant Energy Savings: The shaft power decreases according to the third power of the speed, and the case shows that the energy - saving effect is 20% - 50%. Extended Equipment Life: Soft start and mechanical protection reduce maintenance costs. Intelligent Integration: It is seamlessly connected with the BAS system to realize remote monitoring and automatic management.

Variable Frequency Drives (VFDs) play a critical role in optimizing the performance of Electric Submersible Pumps (ESPs) in oilfield production. By adjusting the power supply frequency, VFDs enable stepless speed regulation of submersible motors, dynamically matching the pump’s discharge capacity to the well’s fluid supply. This adaptive control ensures efficient production, particularly in wells with varying fluid properties such as viscosity and gas content. Technical Principles and Benefits Energy Efficiency: VFDs reduce energy consumption by optimizing motor转速 (speed) to avoid overloading, thereby improving system efficiency. Dynamic Adaptation: Real-time frequency adjustments allow ESPs to maintain stable operation under fluctuating well conditions, enhancing reliability. Extended Equipment Lifespan: By mitigating mechanical stress and reducing abrupt starts/stops, VFDs prolong the service life of motors and pumps. Industry Applications and Challenges Offshore Platform Case: In Penglai 19-3 offshore oilfields, Rockwell Automation’s PowerFlex 7000 medium-voltage VFDs have been deployed to drive ESPs. These systems achieve significant energy savings and stable operation, though challenges like high-order harmonics (which increase copper and iron losses) and end overvoltage (due to long cable transmission) require mitigation through passive filters or motor design optimization. Harmonic Management: VFD-induced harmonics necessitate advanced filtering or adjustments in motor parameters (e.g., slot leakage reactance) to protect insulation systems. ConclusionThe integration of VFDs with ESPs represents a advanced solution in oilfield artificial lift systems, balancing energy efficiency, operational stability, and equipment durability. Continuous advancements in VFD technology, such as multi-level inverters and harmonic suppression, further enhance their applicability in complex well environments. This description synthesizes technical terminology, industry practices, and case studies to provide a comprehensive English overview of VFD applications in ESP systems.

Variable Frequency Drives (VFDs), also known as Adjustable Speed Drives (ASDs), are critical in optimizing the performance of fans and pumps across industrial, commercial, and municipal sectors. By adjusting motor speed to match real-time demand, VFDs significantly reduce energy consumption, enhance system reliability, and enable precise control. Key Applications and Benefits 1. Energy Efficiency and Cost Savings Principle: VFDs leverage the Affinity Laws for pumps and fans, where power consumption is proportional to the cube of motor speed (P∝n3). Even minor speed reductions yield substantial energy savings. Example: Reducing fan speed by 20% lowers power consumption by 50%. Case Studies: HVAC Systems: VFDs achieve 20–50% energy savings in air handling units by adjusting airflow to match occupancy or temperature needs. Water Treatment: A wastewater pumping station in Scotland doubled efficiency after installing VFDs, saving $80,000 in electricity costs over 20 years. Industrial Pumps: A paperboard mill reduced pump duty to 60% under normal conditions, with a 16-month payback period. 2. Enhanced System Control and Reliability Precision Flow Control: In HVAC systems, VFDs enable ±0.5°C temperature accuracy and eliminate pressure swings caused by traditional damper/valve control. Steel plants use VFDs to stabilize轧机 cooling systems, improving product quality. Extended Equipment Lifespan: Soft starting reduces mechanical stress, cutting motor/bearing wear by up to 50%. Municipal sewage pumps using VFDs avoid overflows and extend service intervals. 3. Industrial and Municipal Use Cases Mining and Metallurgy: VFDs optimize energy use in crushers and ball mills, with ton-level electricity savings in cement production. Agriculture: Irrigation systems achieve 20–50% water savings through precise flow control. Data Centers: Retrofitting CRAC units with VFDs reduces fan energy use by 30–70% while maintaining thermal stability. 4. Emerging Trends and Innovations Smart Integration: VFDs paired with IoT sensors and AI algorithms enable predictive maintenance and dynamic energy management (e.g., demand response). Material Advances: Wide-bandgap semiconductors (e.g., SiC) enhance VFD efficiency to >99%, reducing heat loss and footprint. Renewable Synergy: In wind turbines, VFDs stabilize grid integration by managing variable output, while in solar inverters, they optimize DC-to-AC conversion. Technical Advantages Reduced Operating Costs: Energy savings often offset VFD costs within 1–3 years. Compliance: Meets IEEE 519 harmonic standards and supports ISO 50001 energy management. Scalability: Suitable for retrofits and new installations across motor sizes (1 kW to multi-MW). VFDs are transformative in fans and pumps, delivering unparalleled energy efficiency, operational flexibility, and sustainability. As industries prioritize decarbonization, VFD adoption will accelerate, driven by advancements in smart controls and semiconductor technology. From reducing municipal energy bills to optimizing industrial processes, VFDs remain a cornerstone of modern motor control systems.

I. Technical Principles and Core Advantages 1.1 Operating Principles Frequency inverters regulate motor speed to control the air discharge volume of air compressors, achieving constant-pressure output. The core workflow includes: Pressure Detection: Pressure sensors monitor system pressure in real time. Signal Feedback: Pressure signals are transmitted to the frequency inverter. Frequency Adjustment: The inverter modulates the motor's power supply frequency based on pressure signals, altering rotational speed. Discharge Volume Adjustment: Changes in motor speed lead to variations in compressor discharge volume, enabling precise pressure control. 1.2 Core Advantages (1) Energy Conservation Elimination of No-Load Losses: Traditional air compressors operate at full speed even under low demand, while inverters reduce speed to minimize wasted energy. Pressure Band Loss Reduction: Conventional units frequently load/unload within pressure limits, whereas inverters stabilize pressure to reduce energy waste. Soft Start Reduces Impact: Startup current is only 1.5–2 times the rated current (vs. 6–8 times for traditional units), significantly lowering grid shock and energy consumption. Energy Savings Rate: 30–40% energy savings under 60–80% load conditions. For example, a 55kW air compressor saves 130,000–170,000 kWh annually, equivalent to reducing 40–50 tons of standard coal consumption. (2) Equipment Protection and Lifespan Extension Reduced Mechanical Wear: Lower motor loads at partial loads extend the lifespan of bearings and other components. Stable Pressure: Minimizes pipeline leaks and equipment failures. (3) Intelligent Control Integrated PLC and HMI: Enables remote monitoring, data visualization, fault alerts, and self-diagnostics. Communication Protocol Support: Compatible with Modbus and other protocols for seamless integration with upper-level systems. II. Selection Guidelines 2.1 Load Matching Reciprocating Air Compressors (Impact Load): Select inverters with 150% instantaneous overload capacity. Screw Air Compressors (Constant Torque Load): Prioritize low-frequency torque output. 2.2 Power Calculation Formula: Inverter rated power = (Air compressor motor power × 1.1) / 0.92. Electrical Parameters: Grounding resistance < 4Ω, three-phase imbalance < 2%. 2.3 Compatibility and Testing Communication Protocols: Ensure protocol compatibility (e.g., Modbus) between inverters and PLCs. Conduct 72-hour joint debugging, including emergency stops and soft starts. EMI Filter: Mandatory installation at power input to mitigate electromagnetic interference. 2.4 Environmental Adaptability High-Altitude Areas: Output capacity decreases by 6–8% per 1,000m elevation. Use enhanced-cooling inverters. Explosion-Proof Environments: Require ATEX or IECEx certification. III. Typical Application Cases 3.1 Zhejiang Xinfuling Electric Co., Ltd. Solution: H130 dedicated inverter with Pulete controller driving a permanent magnet synchronous air compressor. Advantages: Compact design with 100% transmission efficiency. Motor volume 1/3 of conventional units, facilitating installation. Superior energy efficiency, even at low speeds. 3.2 Shaanxi Mining Company Retrofit Background: Original 132kW fixed-speed air compressor had high startup current and severe pressure fluctuations. Results: Reduced startup current and stabilized pressure. Loading current dropped from 220A to 130A; unloading current from 90A to 50A. 3.3 Pharmaceutical and Electronics Industries Pharmaceuticals: Precise control of gas flow, pressure, and temperature ensures packaging quality. Electronics: Stable high-purity gas output meets semiconductor manufacturing demands. IV. Conclusion Frequency inverters optimize air compressor performance through intelligent speed regulation, delivering energy savings, pressure stabilization, extended equipment lifespan, and intelligent management. Selection requires careful consideration of load type, power matching, environmental adaptability, and compatibility. Case studies validate their significant industrial benefits. With global carbon reduction initiatives, inverter-driven air compressors are poised to become the mainstream choice for industrial energy efficiency.

Overview Mine hoist is an important equipment in the production process of coal mines and non-ferrous metal mines. The safe and reliable operation of the hoist is directly related to the production status and economic benefits of the enterprise. This kind of dragging system requires frequent forward and reverse motor starting, deceleration and braking, which is a typical frictional load, i.e. constant torque characteristic load. Previously, mainly within the gear winch (mechanical drag), hydraulic winch (hydraulic drag) and AC asynchronous motor rotor series resistance speed control winch (electrical drag) and other types of dominant. The power of the inclined shaft hoist is provided by the wire-wound motor, which uses the rotor series resistance speed regulation. The mechanical structure of the inclined shaft hoist is schematically shown in the following figure.   At present, most small and medium-sized mines use inclined shaft winch to hoist, and the traditional inclined shaft hoist generally adopts AC winding type motor series resistance speed control system, and the resistance is controlled by AC contactor- thyristor. This control system is easy to oxidize the main contacts of the AC contactor and cause equipment failure due to the frequent action of the AC contactor during the speed regulation process and the long operation time of the equipment. In addition, the speed control performance of the hoist in the deceleration and crawling stage is poor, often resulting in inaccurate stopping position. The frequent starting, speed regulation and braking of the hoist generates considerable power consumption in the rotor external circuit of the series resistor. This AC winding motor series resistance speed control system is a step speed control, speed control of the smoothness is poor; low speed mechanical characteristics of the soft, static difference rate is large; resistance on the consumption of the differential power, energy saving is poor; starting process and speed shifting process current impact is large; high speed operation vibration, safety is poor. Therefore, the original system in the safety and reliability, speed regulation, energy saving, operation, maintenance and other aspects have different degrees of defects. Since the inverter winch, so that the equipment level of the slope winch has changed qualitatively. At present, the frequency conversion winch has become the dominant product in the market, and its main features are as follows. Compact structure, small size, easy to move, used in underground mines can save a lot of development costs. ZF series frequency conversion winch is based on the full digital frequency conversion speed control, vector control technology as the core, so that the asynchronous motor speed performance can be comparable to the DC motor. The performance of low frequency torque, smooth speed regulation, wide range of speed regulation, high precision, energy saving, etc. Adopting double PLC control system, the control performance and safety performance of the inclined shaft winch is more perfect. Simple operation, safe and stable operation, low failure rate, and basically maintenance-free. Frequency conversion system composition In order to overcome the shortcomings of the traditional AC winding motor series resistance speed control system, the use of frequency conversion speed control technology to transform the hoist, you can achieve the full frequency (0 ~ 50Hz) range of constant torque control. The treatment of regenerative energy, can be used inexpensive energy braking program or energy-saving more significant feed-back braking program. And in the design process of the hydraulic mechanical braking, secondary brake valve and inverter braking to be integrated.  Inverter winch electric control system for single or double drum winding winches driven by AC asynchronous motors (wire-wound or squirrel-cage type). Can be used with the newly installed winches, but also suitable for the technical transformation of the old winch electrical control system. Frequency conversion winch electric control system can be simply divided into: frequency conversion speed control system (frequency converter + brake unit + brake resistor box); PLC control system driver's desk. The composition of the winch mechanical system is shown in Figure: System Features Two-wire system:The PLC control system consists of two main PLC systems.PLC1 is used as the main control system and PLC2 as the monitoring system. Each PLC system is equipped with its own independent position detection element (shaft encoder). During normal operation, the two PLC systems are put into operation at the same time to realize the "two-wire system" control and protection of the winch. In order to ensure that the two PLC systems can work synchronously, the position and speed signals of the two PLC systems are compared in real time within PLC1, and once the deviation is too large, an alarm will be immediately generated. The two PLC systems exchange data mainly in the form of communication Emergency mode: If one PLC fails or its position detection element fails, the single PLC can continue to work in the "Emergency 1" or "Emergency 2" mode. Winch in the emergency mode of work, due to the protection is not missing, but no "two-wire system". However, in order to ensure the safety and reliability of the winch operation, the operating speed is reduced to half speed. If two sets of position detection elements fail, the winch can only run at a speed of no more than 0.5m/s. Dual speed sources: The actual speed in the control system comes from two different speed sources, the inverter and the shaft encoder, and the actual speed involved in the control and overspeed protection is taken from the maximum value of both. Position control: PLC automatically generates the speed giving v(s) with travel as the independent variable, and the speed giving after the equal speed section implements the double giving of v(t) and v(s), and the travel giving v(s) is the main one in both. Semi-automatic operation mode: different from the traditional sense of semi-automatic operation mode, is the use of the driver's console "speed selector switch" to control the winch running speed and work gate opening and closing at the same time, especially for the operation of the inclined shaft winch. The working process of the hoist  After the hoist is transformed by frequency conversion, the working process of the system does not change much. When pushing the handle forward and backward, it can drive the encoder to rotate and send the pulse number to the PLC high-speed counting terminal, which can steplessly adjust the speed of the inverter within a certain range. It can also give "handle zero", "forward" and "reverse" contacts. No matter the motor is forward or reverse, the coal is dragged from the mine to the ground, the motor works in forward and reverse electric state, only when the fully loaded trailer is close to the mouth of the shaft, it needs to decelerate and brake, the hoist working timing diagram is shown in the figure below.