Engineering Notes by Oriental Motor

Improve Motor Performance With Redesigned Compact BLDC Drivers

[fa icon="calendar"] Jun 3, 2019 5:33:13 PM / by Johann Tang

Johann Tang

The BLH Series compact BLDC motors and drivers have been around for a long time, and there is a good reason.  Customers seem to favor the combination of a highly efficient, compact motor and a light weight board type driver that is easy to use.  Having a high torque, flat style hollow shaft gearhead as an option also helps in increasing torque as well as minimizing footprint.

How do we improve something that is already popular?  It's quite simple actually.  We listen to our customers and turn complaints into new features.

Newly redesigned BLH series brushless motor drivers

  • Improvement in Characteristics
  • New Digital Setting Type Driver and MEXE02 Support Software
  • Analog Setting Type vs Digital Setting Type
  • Old vs New Compatibility
  • RS-485 Communication Type Driver
  • Part Number Change
  • Download Brochure
Improvement in Characteristics

Increased Torque

Although there is no design change to the motors, when these new BLH Series drivers are combined with existing BLH Series motors, there is an improvement in torque performance both in the limited duty range and continuous duty range.  The increased torque can help accelerate or decelerate the load faster for reduced tact times.

BLH brushless motor redesign: increased torque

Extedended Acceleration/Deceleration Range & New Stop Modes

With the new drivers, the acceleration/deceleration time setting range has been extended both in the low end and high end.  In addtion, 3 "deceleration stop" modes are provided for more flexibility in stopping the motor.  

Type of BLH Series Driver Acceleration/Deceleration Range
Older Drivers (Analog Only) 0.5~10 seconds
New Analog Setting Type Drivers 0.1~12 seconds
New Digital Setting Type Drivers 0.1~15 seconds
Stop Mode Description
Deceleration Stop 1 The motor generates a braking force when decelerating to a stop, and operates so as to stop according to the set deceleration time setting.  Regenerative power generated by the deceleration of the motor, it is consumed by the motor and driver and won't return to the power supply side.
Deceleration Stop 2 The motor coasts to a stop by suppressing a braking force at deceleration stop.  However, if the deceleration time is shorter than the time that the motor takes to coast to a stop, it will not be applied.
Deceleration Stop 3 The motor generates a braking force when decelerating to a stop, and operates so as to stop according to the set deceleration time.  The regenerative power generated by the deceleration of the motor is returned to the power supply side.

Why did we do this?  For example, in applications such as driving mechanisms for AGVs and AMRs, back EMF generated by back-driving of motors is a major issue.  Using Deceleration Stop 1 could help eliminate power supply and driver issues due to back EMF.  Using Deceleration Stop 3 could recharge the battery for the vehicle.  Just make sure the battery can absorb the regenerative power.

BLH brushless motor with hollow shaft gearhead for AGVs

By combining a wider acceleration/deceleration time setting range with higher torque, these motors can reach target speeds quicker and stop quicker.  Using a longer acceleration/deceleration time helps reduce required torque, so the motors can drive larger inertial loads if necessary.

Lower Noise

Another nice improvement of the updated BLH Series drivers is lower overall noise.  These drivers employ the sinusoidal drive method.  With reduced torque ripple and smooth rotation even at low speeds, the motor's drive noise is reduced by 13 dB.

Decibel comparison

Digital Setting Type Driver and MEXE02 Support Software

The older BLH Series drivers were considered the analog setting type.  Analog setting type drivers allow the speed(s) to be set by an analog voltage signal.  This signal can be provided by an internal potentiometer, an external potentiometer, or a 0~5VDC external signal.

The digital setting type driver is a brand new driver introduced with the updated BLH Series and includes more features and functions to improve the overall performance and ease of use.

MEXE02 Support Software Functions

One major design change was adding a USB connector on the driver board and adding a data setting function via the MEXE02 support software (GUI).  The reason why I mentioned this first is because many of the new features and functions are because of this software, which is used to program the stored data in the driver.

MEXE02 support software for programming motors

Speed regulation comparisonSince we are now "digitally" setting the data instead of relying on an analog signal that can be affected by varying resistance of cables, the speed regulation is improved from +/-0.5% to +/-0.2% (maximum speed fluctuation).  This can help improve synchronous operations with multiple motors. 

With the software, 8 speed data sets are now available.  With the older analog setting drivers, only 2 speeds can be set with either internal potentiometer/external potentiometer or internal potentiometer/external DC voltage.  With digital speed setting, the speed range is also widened a little bit on the low end (100~3,000 RPM vs 80~3,000 RPM), which opens up the BLH Series for more low speed applications.  

With the MEXE02 support software, I/O signal assignments, torque limiting, teaching operation, and remote monitoring are now possible as with our other products that use the same software. 

I/O Signal Assignments 

MEXE02 software: I/O signal assignments I/O signal assignments allow the user to assign the input function they need instead of wasting an input on a function that's not necessary.  Even though you have 6 inputs and 4 outputs physically available, there are 13 input functions and 8 output functions you can assign.

Torque Limiting

Torque limiting is a function to limit the motor's torque to a percentage of the rated torque (100%) by using current and feedback.

Torque limiting example

For applications such as pressure sensitive stamping, pressing, capping or screwing mechanisms, a torque limit function could prove useful. Bottle capping application example

Teaching  Operation

Teaching operation allows speeds to be taught by the software's speed toggle function.   For data synchronization between multiple drivers, a data copy function is available.

Teach/remote operation, operation data copy/reading


Remote Monitoring

Remote monitoring allows monitoring of system status in real time through the MEXE02 software.  Through this function, data such as speed, load factor, driver temperature, load, tripmeter, odometer, I/O status, alarm codes, and power cycles can be monitored by the software.  For predictive maintenance, information bit outputs can be easily configured and connected to the host PLC.

MEXE02 software: monitoring functions

Related PostIntroduction to MEXE02 Support Software for Stored Data Type Drivers (VIDEO) 

Analog Setting Type vs Digital Setting Type

Here are some comparison information that shows the differences between the new analog setting type driver and the new digital type setting driver.

Driver Differences

The digital setting type driver offers more functions than the analog setting type driver.  Select the driver that works for your application. BLH driver type operating data seeting
Use the MEXE02 support software with a digital setting type driver  to access functions ⑦ to ⑭. BLH driver types: functions

Design Change: I/O Connector

A bigger I/O connector has been adopted for the new digital setting type driver.  Changing from a 12 pin connector to a 14 pin connector, the digital setting type driver offers 1 more input and 2 more outputs than the analog setting type driver for a total of 6 inputs and 4 outputs.  Use the digital setting type driver for greater flexibility of control and better status monitoring.  

Pin out diagram comparison: BLH series

PWM Input

The last added feature is an input function that makes these digital setting type drivers even easier to use with host PLCs.  I should bring up at this time that all of the analog input functions (internal/external potentiometers, external DC voltage) are available with the digital setting type driver.  What makes the digital setting type driver unique is its ability to accept a PWM signal from the PLC to set speed (instead of the external DC voltage).  This could help eliminate the extra cost of an analog card on a PLC.

PWM input
Old/New Compatibility

Same Dimensions

The older drivers, new analog setting type driver, and new digital setting type drivers all have the same dimensions, so replacements/upgrades are like hitting an easy button.  Since all the upgraded features and functions are on the driver, users can simply keep the same motor and replace the driver for better performance and control.

Same I/O Specifications

Most of the specifications are kept the same to avoid difficulties in driver upgrades.  For example, we have kept the same C-MOS negative logic (sink) for inputs and transistor open-collector for outputs instead of sink/source photocouplers like in our other drivers, and we kept the number of I/O the same (5 inputs / 2 outputs).  This allows quicker replacement of older drivers without complications.  

If you're looking for more I/O, we'd suggest looking at our digital setting type drivers (6 inputs / 4 outputs).

Motor Connector Location

Let's take a look at the following images for comparison.  Notice that for the new drivers, the motor connector is now on the left side instead of right side.  There's a USB connector on the digital setting type drivers.  Please use a USB2.0 cable to connect to your PC after installing the MEXE02 software.

Older BLH Series Driver New BLH Series Drivers
Analog Setting Type Only Analog Setting Type  Digital Setting Type
Older BLH analog setting type driver BLH analog setting type driver BLH series digital setting type driver

①Power Connector 

②I/O Signal Connector

③Motor Connector

④USB Connector (for digital setting type)

RS-485 Communication Type Driver

BLH series RS-485 communication type driver for BLDC

To cover monitoring or predictive maintenance requirements, or simply to reduce wiring requirements, a new RS-485 communication type driver is available.  Two communication ports are added as well as MEXE02 support software compatibility.  Once connected to a upper level host controller, this driver will be able to send real-time updates on various status data.  Specifications such as speed regulation and speed range will be the same as the digital setting type driver.  RS-485 communication type drivers are not offered for 100 W motors at this time.

Part Number Change

From Packages to Components

One other major change for the updated BLH Series is how we list the part numbers.  Oriental Motor has undergone a major part number change for many products in order to offer more product flexibility to customers.  Let me explain.  If you are a long time customer, we used to offer package part numbers which includes a motor with a dedicated driver for optimal performance and guaranteed specifications.  By listening to our customers' demand for more flexibility of product combinations, we started to switch from package part numbers to individual component part numbers.  This way, customers are not limited to only the package combinations that we recommend.  Customers can now make up their own package using individual components, thus having more freedom to create the best combination possible for their needs.

Part Numbers for Motor and Driver

BLH series motor part number

BLH driver part number

Product Configuration

BLH series product configuration

System Configuration

BLH series system configuration

To make sure you are buying the right components, feel free to Contact An Expert.

For heavier loads or for additional AGV specific functions, we recommend the BLV Series.

We are pleased to introduce the new redesigned BLH Series Drivers. 

Easily replace driver to upgrade motor performance.

BLH Series compact BLDC motors and drivers

BLH Series

Download Brochure

White Paper - AGV / AMR Designs: Understanding Brushless DC Motor Benefits

Watch the BLH Series gear motors work in an AGV!

Watch more demo videos.


Topics: Torque Limit (Push Motion, Tension Control), Robotics, Speed Control, VIDEOS, Capping, BLDC Motors, Software

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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