How can I make mathcad prime use different base units in calculations?

[TS_9501702]

So my starting parameters are P1= 7.5 kW and n1= 750 rpm.

On the left side Mathcad is converting my units to SI which messes with my final results.

For this formula I have to use P1 in kW and n in rpm, which mathcad is changing into W and revolution per second. Right side is how to calculation is supposed to be going by the formula.

Is there a way I can fix this? I saw that in Mathcad 15 you could define a custom unit system. Is there anything like that for Mathcad Prime? 

Thank you!

[LucMeekes]

There is no custom unit feature in Prime. You're not the first to ask for/about it, and probably will not be the last.

So you've changed the unit of the Moment Mt1 from J to N*mm.

You should do the same with the P and the rotations: type a k before the W, and replace 1/s with rpm.

Success!

Luc

[TS_9501702]

That one doesn't work. That is the point of the post 😄 I need Mathcad to use kW as base units

[Werner_E · Accepted solution]

The formula you use has built-in correction factors (60/(2 pi) and 10^6) which are not necessary if you use units in Prime:

[StuartBruff]

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@TS_9501702 wrote:

So my starting parameters are P1= 7.5 kW and n1= 750 rpm.

On the left side Mathcad is converting my units to SI which messes with my final results.

For this formula I have to use P1 in kW and n in rpm, which mathcad is changing into W and revolution per second. Right side is how to calculation is supposed to be going by the formula.

Is there a way I can fix this? I saw that in Mathcad 15 you could define a custom unit system. Is there anything like that for Mathcad Prime? 

Thank you!

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Mathcad hasn't really messed with your units.  You need to tell it (effectively) that your base unit of time is the minute,  

 

or, more specifically, ...

Stuart