... as standard. Siemens and ABB motor are optionalSpeed inverterAn AC Frequency inverter installed in a panel controls the RPM of the ... . Main motors on off, ammeters, voltmeter, emergency stop, inverter trip, indicating lamps, speed control switch, RPM indicator. All ... . Main motors on off, ammeters, voltmeter, emergency stop, inverter trip, indicating lamps, speed control switch, RPM indicator. All ...