The vacuum cleaner motor is generally used in single-phase series motor. This kind of motor with no load has a higher speed. The motor speed can be adjusted within a wide range by changing the load voltage. There are two control methods:

  • Use SCR to adjust the motor power to change the speed phase regulation.
  • Use transformer relay to control motor on or off.

Points of application

  1. Using WT310E/333E is to measure the motor’s rated voltage, consumed power, and input current.
  2. Upper picture is the cleaner circuit with power control circuit. When a trigger pulse is added to gate of the SCR, the state is ON, the polarity of the input AC voltage becomes OFF. Thus, by changing the width of the gate pulse, it is possible to control the motor input current.
  3. Lower picture is the waveform of the motor input voltage. By the choice of hand control regulator stalls, the voltage waveform of the motor is changed. So that the motor speed changes and plays a role in adjusting the vacuum cleaner suction.


  • By average processing to achieve high precision measurement of active power, voltage and current.
  • The bandwidth can capture SCR waveform.
  • For production line testing: GPIB (option), DA outputs (option).

Power Analyzers

Power Analyzers

A power analyzer measures electrical power characteristics of devices that generate, transform, or consume electricity. Also called power meters or wattmeters, these devices measure parameters such as true power (watts), power factor, harmonics and efficiency in inverters, motor drives, lighting, home appliances, office equipment, power supplies, industrial machinery and other devices. Power analyzers also enable engineers to minimize energy loss due to distorted, transient waveforms in power electronics such as inverters, motors, lighting circuits, and power supplies. 

Yokogawa, the world's leading manufacturer of electrical power analyzers, provides a broad selection to satisfy all requirements.