AC Output Chokes
AC Inverters use a fast switching PWM technique to create a variable frequency AC Output to the connected motor. The fast switching of the output of the drive when connected with long motor cables results in a reflected voltage at the motor which can be up to three times the AC supply voltage, with very fast rise time. Output chokes help to reduce this peak voltage, and increase the rise time, to reduce the stress applied to the motor insulation and prevent damage.
Output Chokes are recommended whenever:
- The connected motor is not 'Inverter Rated' or suitable for inverter use.
- The motor cable length exceeds 50 metres (164 ft.) of shielded cable or 75 metres (246 ft.) of unshielded cable. Output chokes MUST be fitted when the motor cable length exceeds 100 metres (328 ft.) of shielded cable or 150 metres (492 ft.) of unshielded cable, and allow a maximum of 200 metres (656 ft.) of shielded cable or 300 metres (984 ft.) of unshielded cable to be used.
- High capacitance motor cable is used.
Please call us on 01905 887 667 if you require assistance speccing the correct size of Output Choke.