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Why Pots are Ideal for Rotary Position Feedback

June 20, 2012


Rotary Position Feedback products: How 10 years can change everything

While technology changes exponentially over time, people often work unaware that such changes have ever happened. And that can cost a company a lot of money.

Take for example Rotary Position Feedback products. Ten years ago, an article in InTech claimed that resolvers were the best choice for minimizing a motor’s rotary error. The author of the article claimed that a resolver has just the right combination of accuracy, resolution, and linearity. He writes, “In this application, the resolver appears to be the best-suited component, due to both the enclosure cost and the relative proximity of the resolver and encoder accuracies.” 

While we agree with the formula he used to come up with this statement, his choice of the resolver is no longer valid. The potentiometer is now the obvious choice. Here’s why.

It says in Step 2 of the article: "changing environmental conditions will introduce significant changes in encoders and potentiometers, due to thermal expansion of dissimilar materials, optical alignment changes, etc." While this may be true for encoders, it is no longer the case for most potentiometers. In fact, there are many potentiometers that perform in extreme environments including hard vacuum and the extreme temperatures of space, nuclear applications and down-hole drilling.

Additionally, the linearity the author references of .25% is no longer relevant. Betatronix can provide linearity to .04%.

Enclosure cost should be nominal. Betatronix produces components that do not require an enclosure, or we can use lightweight, low-cost materials.

And the lower cost of potentiometers should be a primary consideration, especially when potentiometers have made such strides in the last few years – so much that they can now offer similar performance capability.

To learn more about the accuracy, linearity and low cost of potentiometers, talk to one of our expert engineers or representatives.