Is it worth the switch to brushless DC motors?

In the majority of cases the answer will be yes (at least from a technical stand point)

There are immediate benefits to be had from switching to brushless DC motors from AC or brushed DC motors. Some of these are not universally applicable depending on the specific motors being used but in the majority of cases, switching to brushless DC (BLDC) motors will provide the following benefits:

  • Improved power density (more power per unit of weight).
  • Longer life.
  • Increased flexibility and control options over AC and brushed DC motors. 
  • Increased energy efficiency.

OK, I can see there are clear technical and life benefits but what of the financial implications...

Depending on the nature of your application it is possible that the right brushless DC motor will cost more than an equivalent brushed DC motor but it is highly likely that in these instances there will still be reduced costs over the life of the motor.

For example, if the brushed DC motor you require costs £50 and the potential replacement package (let’s say the Zikodrive ZDBL15-42075 brushless DC motor and controller) costs £127. A typical lifespan of a DC motor in normal conditions is around 2000 hours, whereas a brushless DC motor typically averages 10000 hours.

A simple choice?

A simplistic cost per hour of use comparison therefore points to the fact that a brushless DC motor will cost £0.025/hour of use whereas a brushless DC motor and controller will cost £0.0127/hour of use. If one factors in the fact that the brushless DC motor will reduce in efficiency over it’s life as the brushes become worn then this adds to the support for the brushless DC package. 

Furthermore, if one factors in that one would nee to buy 5 brushed DC motors in order to meet the same expected life of the brushless DC system (at a total cost of £250 in this instance) then the equation moves further in the direction of the brushless DC system.

The application is always important

All of the above arguments point to a clear conclusion that brushless DC (BLDC) motors and controllers are ultimately a better option than brushed DC motors but it is also the case that in certain applications brushed DC motors remain the better choice. In audio applications for example, brushed DC motors can offer a smoother performance which is critical to accurate turntable performance. 

Similarly if the lifespan of a particular product is very short, such that the extra expense of the brushless DC system will not be amortised over the life of the product then there is little financial sense in opting for brushless DC (BLDC) motors

Concluding thoughts...

For the majority of applications, the evidence suggests that switching to brushless DC from brushed DC can deliver the following benefits:

  1. Cost savings over the life of the product.
  2. Reduced servicing/maintenance requirement.
  3. Improved power density ratio.
  4. Greater control and performance options.
  5. Significantly longer life.
  6. Consistent and reliable performance over the lifespan of the product.

To find out more about whether brushless DC motors and controllers are right for your particular application why not have a look at our motor control applications and case studies pages. Alternatively, if you would like to talk to one of our team about a specific project or requirement that you have then please contact us here.

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