ZF-R Series Universal Motor Soft Starter

A universal soft starter is an electric motor control device that integrates motor soft starting, soft stopping, light-load energy saving, and multiple protection functions. It is widely used in motor control systems across industries such as industrial manufacturing, construction, and transportation.

I. Working Principle

A universal soft starter controls the conduction angle of three-phase thyristors to regulate the voltage applied to the motor, gradually increasing it during startup to achieve smooth acceleration. The process includes:

1. Initial Stage: The thyristor conduction angle is small, applying a low voltage to the motor and limiting the starting current within a set range.
2. Acceleration Stage: The conduction angle gradually increases, raising the motor voltage and allowing the speed to rise steadily.
3. Running Stage: When the motor speed approaches the rated value, the thyristor becomes fully conductive, and the motor operates at full voltage.
4. Stopping Stage: The conduction angle is gradually reduced to lower the motor voltage, enabling a soft stop.

II. Key Features

1. Smooth Starting: Reduces current inrush during motor startup, minimizing stress on the power grid and mechanical equipment.
2. Soft Stopping: Prevents water hammer effects in pumps and other equipment caused by sudden stops.
3. Light-Load Energy Saving: Lowers motor voltage during light-load operation to reduce energy consumption.
4. Multiple Protection Functions:
   • Overload Protection: Monitors motor current and activates protection when it exceeds the set value.
   • Overvoltage/Undervoltage Protection: Safeguards the motor from voltage anomalies.
   • Phase Loss Protection: Detects phase loss in the three-phase power supply to prevent motor damage.
   • Overheat Protection: Monitors the internal temperature of the soft starter to prevent overheating.
5. Adjustable Parameters: Allows users to customize startup time, startup voltage, current limit, and other settings.
6. Communication Capabilities: Some models support protocols like Modbus and Profibus for integration with upper-level systems or PLCs.

III. Applications

Universal soft starters are suitable for applications requiring smooth starting and stopping, particularly in the following industries and equipment:

1. Industrial Sector:
   • Fluid transport equipment such as pumps, fans, and compressors.
   • Mechanical devices like conveyors, mixers, and crushers.
   • Production lines in textiles, paper, and food processing.
2. Construction Sector:
   • Air conditioning systems, elevators, and fire pumps.
3. Transportation Sector:
   • Traction motors and auxiliary equipment in metros, light rails, and airports.
4. Energy Sector:
   • Oilfield pumping units and coal mine hoists.

IV. Selection Guidelines

1. Motor Power: Choose a soft starter model based on the motor's rated power.
2. Rated Current: Ensure the soft starter's rated current meets or exceeds the motor's rated current.
3. Load Type:
   • Light Loads: Select a standard soft starter for applications like fans and pumps.
   • Heavy Loads: Opt for a soft starter with kick-start functionality for crushers and compressors.
4. Control Mode:
   • Online Mode: The soft starter remains in the circuit continuously, suitable for frequent startups.
   • Bypass Mode: Automatically switches to a bypass contactor after startup to reduce wear on the soft starter, ideal for infrequent startups.
5. Environmental Conditions: Choose a soft starter with the appropriate protection level based on installation temperature, humidity, and altitude.
6. Communication Needs: Select a model supporting the required communication protocol if integration with upper-level systems or PLCs is necessary.

V. Installation and Maintenance

1. Installation Tips:
   • Ensure the soft starter's rated voltage and current match the motor.
   • Install in a well-ventilated environment, avoiding high temperatures, humidity, and corrosive gases.
   • Follow the manual for proper wiring, especially for power, motor, and control signal connections.
2. Routine Maintenance:
   • Regularly check the soft starter's operating status and look for abnormal alarms.
   • Clean the heat sink to prevent dust buildup and overheating.
   • Inspect terminal connections for tightness to ensure good contact.
3. Troubleshooting:
   • Refer to the manual's fault codes for diagnosis if issues arise.
   • Common faults include overload, overheat, phase loss, and communication errors.

GuangDong Zhufeng Electric Co.,LTD established in 2004, is a national high-tech and energy save enterprise with approval by National Development and Reform Commission. Focusing on the development and production and sale of products of “energy saving and control speed and variable speed” , Zhufeng has been a very good supplier for energy saving and automation control solutions . With it’s own brands: “ACI”,“ZFENG”, Zhufeng has developed DLT series products including vector and universal variable frequency drive, servo system, energy saving cabinet, industrial power saver, soft starter etc. Applications including ceramic, machinery, petrochemical, metal, textile, food, papermaking, cement, water supply, plastic injection, central air-conditioning, smart building,etc.