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Welcome to this classroom installment on dc motors. DC motors are motion components that take electrical power in the form of direct current (or some manipulated form of direct current) and convert it into mechanical rotation. The motors do this through the use of magnetic fields arising from electric currents through their windings to spur the rotation of a rotor fixed with an output shaft.

This classroom details the specifics of such operation in dc brush motors, also called permanent-magnet (PM) dc motors … as well as the use of these motor types in various in motion designs. We also cover brushless dc (BLDC) motors. These employ magnets instead of brush-commutator assemblies for commutation to operate much like shunt-wound motors, but with field flux from magnets instead of winding current.

Comparing the different types of dc motors

Where brush dc motors make sense 

Minimizing brush wear

Brush dc motors are a mature technology that’s been around for more than a century. 

Brushed dc motors provide high speed and torque, are simple to operate, and are generally inexpensive.

There are three dc motor subtypes: DC brush motors, dc permanent-magnet (PM) motors, and dc universal motors.  

The automated guided vehicles (AGV) market is booming. According to a study by Research and Markets, the global market for AGVs is set to grow by 10.8% by 2026, reaching USD 3.64 billion. The fields of application are manifold, but we show you the Top 3 highest growth markets for AGVs.

The electronically commutated maxon EC motors stand out with excellent torque characteristics, high power, an extremely wide speed range, and an outstandingly long life span.

maxon DC motors are high-quality DC motors, equipped with powerful permanent magnets.

Formulae Handbook: This comprehensive collection with illustrations and descriptions, includes formulas, terms, and explanations for the calculations concerning drive systems. 

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The R&D activities of maxon are directed towards the requirements of the market and the customer. 

Explanation of sinusoidal commutation 

Brushless dc motor basics

Avoiding torque ripple

Although the back EMF waveform of a brushless dc (BLDC) motor is theoretically trapezoidal, in reality, inductance in the motor smooths the back EMF into a more sinusoidal shape. 

Torque ripple—variations in torque production during shaft revolution—is an undesirable effect that occurs in permanent magnet motors, preventing smooth motor rotation.

Brushless dc (BLDC) motors are dc motors that use magnets instead of brushes and a commutator for commutation. 

Differences between slotted and slotless motors 

Difference between EC motors and BLDC motors  

External-rotor motor basics

Conventional brushless dc motors are constructed with a permanent magnet rotor located inside a wound stator. 

Deciphering motor terminology can be frustrating, especially when comparing the operation and performance of various motor types.

The original brushless dc (BLDC) motors were designed with slotted stators, and the majority of BLDC motors are still made this way.  

FAQ: What’s the difference between torque constant, back EMF constant, and motor constant?

What’s the difference 

between cogging torque 

and torque ripple?

FAQ: What are rotational losses in dc motors?