Is it possible to display RPM in Altivar 312 drive.

Yes, to display RPM, go to the [Monitoring] (SUP-) menu and select SPd3 and press enter.

Go to the SET menu and select SdS for the scaling value.

Example: Display motor speed for

4-pole motor, 1500 rpm at 50 Hz (synchronous speed):

[Scale factor display] (SdS) = 30 [factory setting]

[Cust. output value] (SPd3) = 1500 at [Output frequency] (rFr) = 50 Hz