Community Tip - Learn all about PTC Community Badges. Engage with PTC and see how many you can earn! X
I am using Mathcad Prime Release 7.0 and Datecode7.0.0.0
I'm trying to calculate power loss in a motor and rpm will not work as a unit of measure. Also Radians per second also does not work when I convert it from rpm*2PI/60.
Here are the errors that I faced
rpm: not a valid unit.
(Before calculating the output power of the motor, convert speed from units of RPM to rad/sec.)
when trying to calculate: Nm* rad/sec to watts it gives me s*W in the answer.
Solved! Go to Solution.
when trying to calculate: Nm* rad/sec to watts it gives me s*W in the answer.
Do you mean you don't see the results shown in the pic below when you type in these expressions?
Be ware that rpm is defined in Mathcad as 2* pi rad / (60 s)
and revolution (rev) is defined as 2pi (or 2 pi rad), not as 1.
Is "not a valid unit" the exact error message you get or is it something like "These units are not compatible" or "This variable is undefined" ?
You sure should show at least a screen shot including the error message - better of course is attaching the worksheet as well.
Hi,
Make sure you ensure each unit is labelled as a unit (text is blue on default settings)
Go to Math | Style | Labels | Unit to change any that are not units
Hi,
Can you upload your worksheet?
Cheers
Terry
Ok, I had Base Units selected. I changed that to Unit System: SI and rpm started being recognized. It works now. Thank you.
when trying to calculate: Nm* rad/sec to watts it gives me s*W in the answer.
Do you mean you don't see the results shown in the pic below when you type in these expressions?
Be ware that rpm is defined in Mathcad as 2* pi rad / (60 s)
and revolution (rev) is defined as 2pi (or 2 pi rad), not as 1.
Is "not a valid unit" the exact error message you get or is it something like "These units are not compatible" or "This variable is undefined" ?
You sure should show at least a screen shot including the error message - better of course is attaching the worksheet as well.
Ok, I had Base Units selected. I changed that to Unit System: SI and rpm started being recognized. It works now. Thank you.
Mathcad (even Prime) does an excellent job of managing units. Including unit conversions.
The Mathcad unit "rpm" has 2 pi built in so that it will handle angular speed correctly. Note that the companion unit "Hza" has that too!
Prime 4 (Express) file attached, should open and execute in 7.