FAQ A03 - Powertrain: What is the sign convention of the mechanical and powertrain libraries in Simcenter Amesim?

Category: Simcenter Amesim

Topic: Applicative solutions

Access Level: End User

Publish Date: November 2013

Question

Powertrain: What is the sign convention of the mechanical and powertrain libraries in Simcenter Amesim?

Answer

A positive torque is applied to a rotary inertia as shown in the following figure. The result is a negative rotary velocity for this inertia:

This is due to the sign convention on the inertia fixed by the arrow on the icon. The chosen sign convention is such that by construction, the velocity signs on the two connecting ports of an inertia are different, one is the opposite of the other.

The rule is: if a positive torque is applied on a port, the velocity on this port is negative and it is positive on the other port.

You can find more details about sign conversion in Powertrain Library User’s guide 3 Sign Convention.