Rockwell Automation 20P PowerFlex Digital DC Drive - Manual (Page 267)

Rockwell Automation Publication 20P-UM001I-EN-P - February 2013 267
Application Notes Appendix C
Example 1: Armature Voltage (Overvoltage Fixed at 20%)
Because armature voltage feedback is being used the maximum reference and
feedback speeds must be equal and set to the rated speed of the motor (in other
words, field weakening is not permitted).
• Par 175 [Rated Motor Volt] = 500V (default)
• Par 45 [Max Ref Speed] = 1750 rpm (default)
• Par 162 [Max Feedback Spd] = 1750 rpm (default)
• The reference and feedback resolution = 0.21 fpm/count
(5250 fpm/25000 counts)
Example 2: DC Tachometer with No Feedback Bypass
When a DC tachometer is configured, the maximum feedback speed must be
scaled to the maximum voltage of DC tachometer. Leaving Par 562 [Anlg Tach
Gain] at its default value (1.0000) will result in a loss of feedback resolution
because the drive is only using 1750 rpm out of the maximum 3600 rpm.
• Par 175 [Rated Motor Volt] = 500V (default)
• Par 45 [Max Ref Speed] = 1750 rpm (default)
• Par 562 [Anlg Tach Gain] = 1.0000 (default)
• Par 585 [Overspeed Val] = 1925 rpm (default)
• Set DIP switch S4 = 180V
This value is set to the next highest DIP switch setting available based on
the result of the following calculation:
• Set Par 162 [Max Feedback Spd] = 3600 rpm
This value is based on (180V/50V) =3.6 (1000)
• The reference resolution = (5250 fpm/25000 counts) = 0.21 fpm/count
• The feedback resolution = 0.62 fpm/count
Tachometer x Max Motor Speed x Overspeed Percentage = Scaled Tach Input Volts
(50V/1000 rpm) (1750 rpm) (1.1) 96.25V