Motor Load Transducers (Motor kW and Shaft Power Transducers)

Motor load transducers measure the true power drawn by a motor and convert it into a standard analogue signal for PLC, SCADA or panel instruments. By using power based measurement in kW or percent load, Unipower motor load transducers give a clear indication of shaft power and torque without the need for mechanical torque sensors, pressure switches or flow meters. This makes them ideal where you want accurate motor load feedback for monitoring, data logging and process control.

🔧 How Motor Load Transducers Work

• True power measurement: The transducer measures motor voltage and current on three phase supplies and calculates real power in kW. Changes in mechanical load on the shaft show up directly as changes in measured motor kW.
• Standard analogue outputs: The measured load is scaled to a standard output signal such as 0-20 mA, 4-20 mA or 0-10 V, allowing direct connection to PLC analogue inputs, recorders or displays.
• Percent load indication: Many devices can be scaled so that the analogue output represents percent of rated load, making it simple to set alarms, limits and process interlocks in the PLC program.
• Compensation for mains variations: Because the device calculates real power rather than using only current, it automatically compensates for mains voltage changes and power factor variations. This gives a more stable and accurate indication of true shaft load.
• Flexible current ranges: Smaller motors are measured directly through the transducer within its internal current range, while larger motors use external current transformers (n:5 or n:1) to extend the current range.
• Digital processing: Microprocessor based measurement allows filtering, averaging and offset correction so that the analogue output follows the mechanical load, not electrical noise or short term disturbances.

✅ Benefits of Unipower Motor Load Transducers

• Provide a clean, standard analogue signal for motor kW or percent load, ready for PLC and SCADA systems.
• Give a much clearer picture of shaft power than simple current transducers or power factor based systems.
• Reduce the need for separate flow, level or torque sensors in many pump and conveyor applications.
• Support predictive maintenance by showing trends in motor load over time and highlighting gradual changes due to wear or fouling.
• Allow energy and efficiency monitoring at individual motor level, helping identify underloaded or overloaded machines.
• Can be combined with motor load monitors and PLC logic to implement advanced protection and process control strategies.

🚀 Typical Applications for Motor Load Transducers

• Pumps and fans: Use motor kW as a process signal for flow related control, dry run detection, filter monitoring and efficiency checks.
• Conveyors and feeders: Monitor load on screw conveyors, belt conveyors and feeders to detect jams, blockages and variations in throughput.
• Crushers, grinders and mixers: Use shaft power as an indication of product density, viscosity or grind level and feed this back to the control system.
• Compressors and blowers: Track motor power to detect abnormal operating conditions or to control staging and load sharing.
• General machine and process monitoring: Add motor load as a key process variable for batch control, end point detection and optimisation of mechanical drives.

Unipower motor load transducers make it easy to bring accurate motor kW and shaft power information into your control system. By measuring real power directly at the motor, they provide a reliable, sensorless way to monitor mechanical load on pumps, conveyors and other driven machines.

Choosing the Right Motor Load Transducer

• Output signal type: Decide whether your PLC or SCADA system needs 0-20 mA, 4-20 mA or 0-10 V, and select a transducer with the appropriate output range.
• Voltage and current range: Check that the transducer covers the mains voltage and motor current. Use standard current transformers where higher currents are involved.
• Scaling and configuration: Choose a device that can be scaled to the required kW range or percent load range, with simple front panel or parameter setup.
• Mounting and environment: DIN rail or panel mounting versions are available. Consider enclosure rating and ambient temperature for the installation location.

Motor Load Transducer FAQs

• Q: What is a motor load transducer?
  A: A motor load transducer is a measurement device that calculates the true power drawn by a motor in kW and converts it into a standard analogue signal such as 4-20 mA or 0-10 V. This signal represents motor load or shaft power and can be used by PLC and SCADA systems for monitoring and control.
• Q: How is a motor load transducer different from a motor load monitor?
  A: A motor load transducer focuses on measurement and provides an analogue output for a control system. A motor load monitor includes in built setpoints and output relays to trip or alarm when load limits are exceeded. Transducers are ideal when protection logic is handled in the PLC or SCADA system.
• Q: Why use a motor load transducer instead of a simple current transducer?
  A: Current transducers measure only current and do not compensate for changes in voltage or power factor. A motor load transducer calculates real power in kW, which is directly related to torque and mechanical load on the shaft, giving a more accurate and stable signal for process control and monitoring.