... .4-315KW ,0.01-650HZ ZY-A900 series of AC drives is our newest product of sensorless vector control type ... running.Built-in PID adjustingEasy to realize a system for process closed-loop controlOperation FunctionFrequency SettingPotentiometer or external analog ... , tele-control panelProtection FunctionInput out-phase, input under-voltage, DC over-voltage, over-current, over-load, current stall, over ...