In measurement, a nominal value is often a value existing in name only; it is assigned as a convenient designation rather than calculated following usual methods. The use of nominal values can be based on some technical standards. All real measurements have some variation depending on the accuracy and precision of the test method and the measurement uncertainty. The use of reported values often involves engineering tolerances and in various subfields of engineering, a nominal value is one for which the “name” for the value is close to, but not the same as, the actual value. For example, a machine is designed to deliver its nominal power while operating at its nominal speed and voltage, often stated on the device’s nameplate. Actual operating conditions may vary. Therefore, to avoid problems and misunderstanding with the client, we suggest to read this document and to always take it into consideration especially in the electric machines field.