Furthermore, the motors will be suitable for continuous running at rated output (at ambient temperature and at the voltage and frequency values defined in the project documents) with voltage and frequency variations exceeding the limits of ”zone A”, within zone B, but without exceeding the temperature rise permitted by the insulation system of thermal class B by more than 10K.Furthermore, the motors will be suitable for continuous running at rated output (at ambient temperature and at the voltage and frequency values defined in the project documents) with voltage and frequency variations exceeding the limits of ”zone A”, within zone B, but without exceeding the temperature rise permitted by the insulation system of thermal class B by more than 10K.Unless indicated otherwise in the project documents, the motors will be suitable for continuous running at rated output (at ambient temperature and at the voltage and frequency values defined in the project documents) with variations of voltage and frequency within the limits of “zone A” (defined in the standard IEC 60034-1), without exceeding the temperature rise defined for the insulation systems of thermal class B (80K).