What is Rated Torque?
Simply put, rated torque is the maximum output torque value at which an electric valve can operate stably over the long term.
Why is it so important?
Prevents motor overload and burnout: Exceeding the rated torque causes a surge in motor current, leading to insulation damage.
Ensures valve sealing performance: Insufficient torque results in incomplete closure, triggering leaks.
Extends equipment service life: Proper torque matching minimizes mechanical wear and tear.
1. Before purchasing, you must accurately calculate the torque required for your specific operating conditions:
Base Torque: The fundamental force required to open and close the valve.
Operational Adjustments: Account for the influence of media pressure, temperature, viscosity, and particulate content.
Example: A DN200 gate valve requires 200 N·m of torque when operating with clear water at ambient temperature. However, if the medium changes to high-temperature oil, the actual torque requirement may increase by 30–50%.
2. Matching Principle: Better to Oversize Slightly than Undersize-Aim for Reasonable Redundancy
Adhere to the "1.5x Safety Factor" principle:
However, avoid "using a sledgehammer to crack a nut"-excessive torque can lead to:
Wasted procurement costs
Increased energy consumption
Excessive stress on the valve stem and sealing surfaces
3. Pay Attention to "Stall Torque"-A Hidden Parameter
In addition to rated torque, stall torque is equally important. It represents the maximum torque the motor can output at the instant it stops rotating; typically, this is 2 to 3 times the rated torque. This parameter determines whether the valve can overcome sudden jamming or obstructions.
4. Certifications and Test Reports: Look for Results, Not Just Ads
Require suppliers to provide torque test reports issued by authoritative third-party agencies.
Conduct spot checks during on-site acceptance testing to verify the actual torque output.
