Time increase and decrease will change the voltage. Therefore, we need to set the max value ofvoltage when changing the frequency. Moreover, we can base on the max value to limit the frequency.We need to pay attention that under-frequency will greatly change the voltage and the freqiemcyconverter will be tripped. The general condition is based on the normal load, we select longer than thedeceleration time and acceleration time. Then, we need to observe if there has overlarge voltage orelectric current when start or stop the machine. If the machine can start or stop normally, we shouldshorter the declaration time and acceleration time. This is the continuous operation and we finallywork out the proper time.