Engineering Notes by Oriental Motor

Why Brushless Motors Make Sense for Conveyors

[fa icon="calendar"] Aug 31, 2023 6:53:31 PM / by Johann Tang

Johann Tang

In today's fast-paced industrial landscape, the role of conveyors has become more crucial than ever. These systems efficiently move materials, products, and goods, for numerous industries, from labeling and packaging to warehousing and distribution.  While many types of motors can be used in conveyors, we would like to focus on a few reasons why brushless motors should be considered for most conveyor applications.

 

Types of Motors Used for Conveyors

There are several types of motors that are typically used by conveyors; depending on the type of conveyor.  

For fixed-speed conveyors where the speed is constant, AC induction motors are typically chosen for their cost-effectiveness and ease of use.
For variable-speed conveyors where multiple speed settings are necessary, either VFD-driven AC induction motors or brushless motors are typically chosen.  
For indexing conveyors where repeatable stops are required, stepper motors are generally chosen for their stop accuracy.  However, heat generation and duty cycles must be considered.

 

Generally, brushless motors can be used for both variable-speed and start/stop conveyors if servo or stepper motor accuracy isn't necessary.  Furthermore, they offer several advantages that other types of motors do not.

 

Comparing Brushless Motors to Other Motors

When compared to VFD-driven AC induction motors or brushed DC motors, closed-loop brushless motors bring a new level of compactness, speed accuracy, wider speed range, and efficiency. By using permanent magnets in its rotor and no brushes, a brushless motor is more efficient by design and smaller in size.  With built-in closed-loop feedback by encoder or hall-effect sensors, brushless motor drivers constantly monitor and adjust the motor performance, ensuring consistent speeds even under varying loads. The closed-loop systems also enable brushless motor drivers to seamlessly integrate with other automated processes, contributing to a seamless and optimized workflow.

When compared to high-performance servo motors, which can generate high peak torque and also utilize closed-loop feedback in a PID loop, brushless motors present an alternative in cases where servo motors are oversized and overspec'ed.  Due to the required encoder feedback by servo motor systems, servo motors are generally longer.  Brushless motors are also easier to drive than servo motors, which means simpler designs and thus lower cost.

When compared to stepper motors, a brushless motor is actually structurally similar in the sense that there are permanent magnets in the rotor and copper windings in the stator.  It also operates like one with power and phase excitation provided by a dedicated driver, but the similarities stop there.  The lower number of poles and lack of holding torque are the main reasons why brushless motors do not offer the same stop accuracy as stepper motors.  Stepper motors are designed for positioning applications with a limited duty cycle. While closed-loop control can optimize efficiency and performance, brushless motors are designed to run continuously at higher speeds and are a better match for variable-speed conveyors.

 

The table below summarizes the differences between AC motors, brushless motors, and servo motors.
BLDC, VFD-driven AC, and Servo Motor Comparison

 

The Case for Brushless Motors

A brushless motor is generally smaller and lighter than other types of motors.  However, these advantages are amplified when a brushless motor is compared to an AC induction motor.  A brushless motor is smaller than an AC induction motor because it is more efficient and uses permanent magnets.  Therefore it does not have the same losses that occur during electromagnetic induction.  A brushless motor also always runs at synchronous speed; while an AC motor runs at rated speed, which can be several hundred RPMs slower than synchronous speed according to load.  

 

Brushless DC motor vs AC motor size comparison Brushless motors vs AC motors: change in efficiency by speed

 

To further reduce its size, Oriental Motor's newest brushless motors combine an optimized magnetic design with high-performance magnetic steel sheets and permanent magnets.  Closed-loop speed regulation for Oriental Motor's brushless motors is rated at +/-0.2% for motors with hall-effect sensors and up to +/-0.05% for motors with encoders.  With a small overrun that ranges from +/-0.1 to +/-0.4 revolutions according to the RPM and load inertia, brushless motors can also run some indexing conveyors.  However, start/stop frequency and accuracy must be tested.

 

brushless motor rotor and stator design New brushless motor connector and cable
Long-Life Type Watertight JB Gear Type JV Gear Type Right-Angle Flat Hollow Shaft
Parallel Shaft Brushless Gear Motor IP67 Rated Brushless Motor Parallel Shaft (Foot Mount) Brushless Motor JV Gear Brushless Motor Right-Angle Hollow Shaft IP66 Brushless Gear Motor Brushless Motor with Hollow Shaft Flat Gear

 

With a wide lineup between 30 W and 400 W and different AC-input driver options, oversizing can be avoided with no sacrifice to performance.  A variety of gear options are provided for even the smallest frame sizes, so even the smallest requirements can be sized properly.  One major difference between Oriental Motor's brushless motors and other brushless motors is that we offer several different frame sizes for different wattages; while other manufacturers tend to keep the same frame size and increase the length of the motor.

 

Recommended Product Series by Conveyor Type

In this section, we highlight two types of conveyors that our AC-input brushless motor systems are typically used for: single-axis, modular, low-profile conveyors and packaging /labeling conveyors.

 

Single-Axis Modular Low-Profile Conveyors Recommended: BMU Series

Box conveyor with BLDC motor

 

For single-axis modular low-profile conveyors with basic speed control requirements, a BMU Series brushless motor and dedicated variable speed driver are recommended.

The simplicity of the BMU Series and ease-of-use of the front digital panel as well as easy connection makes it perfect for quick installation on single-axis, modular conveyors.  The small size of the motor and driver helps reduce the footprint of the conveyor.  The dedicated driver comes with built-in functions such as load factor and speed limits.

 

BMU Series: easy wiring and speed setting

 

BMU Series: simple speed setting by dieal

 

Packaging and Labeling Conveyors Recommended: BLE2 Series

Food packaging conveyor

 

For conveyors with advanced requirements, such as for packaging and labeling, a BLE2 Series brushless motor and dedicated variable speed driver are recommended.

Up to 16 speeds can be set via the control panel, external potentiometer, external analog voltage, or MEXE02 data setting software.  To run a grip conveyor that has two motors running two belts on each side of the product being transferred, an HMI can output an analog voltage to control 2 drives at the same time as well as output commands to each driver via I/O.  The driver comes with functions such as load factor, torque-limiting, and speed teaching.

 

BLE2 Series: flexible speed setting methods

 

Summary

A brushless motor's high efficiency, small footprint, and tight speed regulation meet the design requirements of a compact variable-speed conveyor.  While it presents many advantages over a VFD-driven AC motor, it can also replace servo motors in certain applications.

While brushless motor design is similar among many manufacturers, Oriental Motor's brushless motors are offered in many frame sizes instead of longer stack lengths.  Make oversizing a thing of the past.  Contact our team for a motor sizing consultation today to find the perfectly sized motor for your application.

We know how you like charts.  Here's a comparison of our two most popular AC-input brushless motor systems.  For multi-axis network control, please ask our team for other motor options.

 

Series BMU Series  BLE2 Series
  BMU Series Brushless DC Motor Speed Control Systems BLE2 Series Brushless DC Motor Speed Control Systems
Equipment
  • Modular/low-profile conveyor
  • Tabletop device
  • Packaging
  • Labeling
Ideal Application Example Single-axis drive Side-by-side conveyor
Wattages 30 W (1/25 HP) , 60 W (1/12 HP), 120 W (1/6 HP),
200 W (1/4 HP), 300 W (2/5 HP), 400 W (1/2 HP)
Gear Types Parallel, right-angle, hollow-shaft Parallel, right-angle, hollow-shaft
Key Features
  • Compact
  • Lightweight
  • Modular
  • Easy wiring
  • Easy setting
Functions
  • 4 speed settings
  • I/O: 5 dedicated
  • Speed limits, load factor
  • Speed attainment band
  • Alarms and monitoring
  • 16 speed settings
  • I/O: 12 dedicated
  • Electromagnetic brake option
  • Speed limits, load factor
  • Torque limiting
  • Speed teaching
  • Alarms and monitoring

See all AC and DC input brushless motor and driver options.

 

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

Johann Tang

Written by Johann Tang

Johann Tang is a Product Specialist at Oriental Motor USA Corp. with over 15 years of experience supporting technical applications of various types of fractional horsepower electric motors, gearheads, actuators, drivers, and controllers; including motor sizing, product selection, technology training, programming, and troubleshooting.

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