Speed Actual (Ac/Dc Drive Object) - ABB FDNA-01 User Manual

86 Communication profiles

Speed Actual (AC/DC drive object)

This attribute indicates the actual speed at which the drive is
operating. The units are scaled by the SpeedScale attribute of the
AC/DC drive object. See Table 4. for details.
Scalar mode
When the drive is operating in the scalar mode, the drive provides
the adapter module with a frequency actual. The ODVA AC/DC
drive profile uses rpm units for the speed actual. The ODVA Speed
Actual is calculated as follows:
where
Osa = ODVA Speed Actual
Dfa = Drive frequency actual in Hz
Us = ODVA speed unit (see
Mf = Motor nominal frequency in Hz
Mss = Motor synchronous speed in rpm (not motor nominal speed)
For example, for a 4 pole 60 Hz motor (Mss = 1800 rpm) with a unit
of 1 rpm and a Drive frequency actual of 30 Hz, the ODVA Speed
Actual is:
=
Osa
10 ODVA SPEED SCALE
×
Dfa Mss
=
Osa
×
Mf Us
×
Dfa Mss
×
Mf Us
×
30Hz 1800rpm
=
×
60Hz 1rpm
on page 41)
=
900