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I have a stepper motor that turns at 5000 PPS and has a step angle of 1.8º.

What would be the formula to transform these PPS into RPM?

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2 Answers 2

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Using dimensional analysis, and cancelling out units (i.e., "dimensions") just like they are numbers, gives you a clear answer: $$ \frac{1 \ step}{pulse} \ \times \frac{5000 \ pulse}{1\ sec} \times \frac{1.8 \ degrees}{1 \ step}\times \frac{1 \ revolution}{360 \ degrees}\times \frac{60\ sec}{1\ min} = \frac{1500\ revolution}{min} $$

step, pulse, sec, degrees all cancel out, leaving an answer in revolutions/min

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With a step angle of 1.8 degrees and 360 degrees in a single revolution, that's 200 steps per revolution (i.e. 360 / 1.8).

So 5000 pulses per second equates to 25 revolutions per second (i.e. 5000 / 200), which is 1500 rpm (i.e. 25 * 60).

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  • \$\begingroup\$ Its amazing how maths is independent of different thought processes. 2 people arrive at the same answer using maths but through different lines of thought! \$\endgroup\$
    – crowie
    May 6, 2016 at 15:11
  • \$\begingroup\$ Same process, actually. I was just a tad more descriptive so the asker might be able to follow along a bit more readily (teach a man to fish....). \$\endgroup\$
    – Scott Seidman
    May 6, 2016 at 15:53
  • \$\begingroup\$ @ScottSeidman Yes, my answer is how I was taught to fish, at least the OP has two approaches to choose from. I remember dimensional analysis from my first year in A level physics in 1976 and it can be a very useful tool. \$\endgroup\$
    – Roger Rowland
    May 6, 2016 at 17:54

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