There are 4 classes for duty classification purposes. They are:
- SLD – Super light duty. (startup current: 110% for 60sec and 120% for 3sec – of the FLA value)
- LD – Light Duty (startup current: 120% for 60sec and 150% for 3sec – of the FLA value)
- ND – Normal Duty (startup current: 150% for 60sec and 200% for 3sec – of the FLA value)
- HD – Heavy Duty (startup current: 200% for 60sec and 250% for 3sec – of the FLA value)
These are being determined by the application details to which the VFD inverter drive must be applied to.