214 Rockwell Automation Publication 2198-UM001M-EN-P - November 2022
Appendix D Motor Control Feature Support
Basic Volts/Hertz for Fan/Pump Applications
The Basic Volts/Hertz Fan/Pump (fan/pump) method is based on the Basic
Volts/Hertz (VHz) method, but is tailored for fan/pump applications.
Figure 115 - Output Voltage Equation
For maximum system efficiency, fan/pump loads use variable-frequency
drives that are equipped with a specific VHz curve where the voltage is
proportional to the square of the frequency.
Figure 116 - Basic Volts/Hertz Fan/Pump Method
V
2
x
=
f
x
f
n
V
n
– V
boost
+ V
boost
Where:
V
x
= Output voltage
f
x
= Output frequency
V
n
= Rated voltage
F
n
= Rated frequency
V
boost
= Run boost voltage
Voltage
Frequency (Hz)
Frequency,
max
Base Frequency
(nameplate)
Base Voltage
(nameplate)
Run Boost
Voltage, max
The Fan/Pump control method supports the run-boost attribute, but does not
support break-voltage, break-frequency, or start-boost.