Minimizing the Effect of Load Fluctuations for Mixers

The viscosity change in liquids can vary the torque required for mixing.  For AC asynchronous motors such as AC induction motors, the rated speed is affected by load torque fluctuations, which may cause inconsistency in the final product.  Is there a better motor for the job?

Problems with Conventional Equipment

The viscosity can change during mixing.  This causes the load torque to fluctuate, which changes the speed of the motor, resulting in inconsistent quality.

Brushless motors operate with closed-loop feedback from hall-effect sensors.  This ensures tight speed regulation even with load fluctuations.  Compared to AC motors, brushless motors are also much more efficient and therefore more compact.  The constant torque output from brushless motors also ensures the same torque being applied (up to rated speed).  Brushless motors also offer a wider speed range when compared to AC motors driven with VFDs.  

Smaller and Lighter Design

Upgrade an AC motor to a brushless motor for smaller and lighter designs.  More details can be found in the comparison table below.

Comparison Between AC Induction Motors and Brushless Motors (Round-Shaft Type)

	BMU Series	BLH Series
External View
Power Supply Input	Single-Phase 100-120 VAC Single/Three-Phase 200-240 VAC	24 VDC
Output	30 W, 60 W, 120 W, 200 W, 400 W	15 W, 30 W, 50 W, 100 W
Speed Regulation (Load)	±0.2% (Digital)	±0.5% (Analog), ±0.2% (Digital)
Speed Control Range	80~4000 RPM	80~3000 RPM
Speed Setting Method	Digital	Digital/Analog/RS-485

TIP: for low speed applications

Brushless motors cover a wider speed range than AC motors driven by VFDs.  This means that brushless motors can operate at a lower RPM and higher RPM.  For example, the can operate as low as 0.01 RPM (with a 200:1 gear ratio).  The reason is because the BXII Series brushless motors use encoders instead of hall-effect sensors.

For mixers or agitators that are used for food applications, brushless gear motors with H1 food-grade grease are available.  Gear motors with H1 food-grade grease are currently available from BMU Series and BLE2 Series.  Please contact our technical support team for more information.

Thanks for reading this post.  Here are some videos for the products discussed in this post.

Here's a video introducing brushless motors as the new standard in speed control.

Here's a video of a BMU Series brushless motor with its speed controller (driver) on a belt conveyor.

Here's a video of BLH Series brushless motors demonstrating driving and steering in an AGV.

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