Engineering Notes by Oriental Motor

Easily Synchronize Speeds of Multiple Motors

[fa icon="calendar"] Oct 15, 2018 9:00:00 AM / by Johann Tang

Johann Tang

There are a variety of ways to synchronize the speed of multiple motors.  In this blog post, we will explain another advantage of using brushless motors systems, which is its ability to set speeds accurately and be able to synchronize speeds on multiple axes easily .  Brushless motors utilize built-in hall-effect sensors to regulate speed.  Even if the load, input voltage, or temperature fluctuates, the speed regulation will always be under +/-0.2% or better.

Grip conveyor with 2 AC motors

An ideal application example is shown below with a grip conveyor that has two belts on either side, driven by two 3-phase AC induction motors.  The speeds of the two motors are controlled by an inverter (VFD).   For a specific labeling operation where a specific side of the bottle has to be labelled, the speeds between the two motors must be synchronized.  Since AC motors do not use feedback speed control, the typical speed regulation of AC induction motors can be -3% to -15%.


Challenge  Synchronize the speeds of two belts for consistent label/print application


Conventional Equipment: Grip conveyor with two belts on each side driven by two different 3-phase AC induction gear motors.  The speeds of the two motors are controlled by inverters (VFDs).  

Problems with Conventional Equipment:

  • An inverter (VFD) does not require feedback from the motor to operate.
  • Speeds of the two belts can vary due to load or friction and causes inconsistent labeling.
  • Fine speed adjustments are difficult with inverters (VFDs).


Solution BMU Series brushless gear motor + AC input driver

Use two BMU Series brushless gear motors with AC input driver to easily synchronize speeds of the 2 belts driven by the motors.  For example, when the speeds are set to 3,000 RPM at the motor, the speed regulation is +/- 6 RPM at the motor (or +/-0.3 RPM with a 20:1 gearhead).  The speed can be set digitally in 1 RPM increments at the motor.  The dedicated driver can also display speed in revolutions or meters per minute.  The last step is to make sure that both drivers receive the start input signal at the same time.

Grip conveyor with 2 BL motorsBMU Series right angle gear motor & driver

Advantages offered by BMU Series: 


  • Eliminates speed variation
  • Guaranteed speed regulation
  • Fine digital speed setting
  • No tuning
  • Quick setup
  • IP66 motor+cable


Learn More About BMU Series


Result +/-0.2% speed regulation between two belts


Watch how speed synchronization performance can be improved with brushless motors.


Thanks for reading this post. 

Watch more product & training videos or read more about brushless motor technology.


Topics: Conveyor, AC Motors, Speed Control, VIDEOS, BLDC Motors, Washdown, Application Examples

Johann Tang

Written by Johann Tang

Johann Tang is a Product Specialist at Oriental Motor USA Corp. with 20+ years of experience in sales, technical application support, and training of various types of fractional horsepower electric motors, gear motors, actuators, drivers, and controllers. Feel free to ask him questions on Linkedin.

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