Time to change pressure in a VFD fan
Time to change pressure in a VFD fan
(OP)
I need to know how long it takes to change from one pressure point to another pressure in a VFD fan.
For example, from 250Pa to 500Pa.
My scenarios is once the fan gets signal to increase pressure differential from the controller, how long do I need to wait until the pressure level gets to the desired level?
And from where can I know how would be output air velocity out of the fan?
For example, from 250Pa to 500Pa.
My scenarios is once the fan gets signal to increase pressure differential from the controller, how long do I need to wait until the pressure level gets to the desired level?
And from where can I know how would be output air velocity out of the fan?





RE: Time to change pressure in a VFD fan
RE: Time to change pressure in a VFD fan
http://www.smacna.org/
How long the pressure change takes depends upon lots of variables and you haven't given enough information to estimate.
RE: Time to change pressure in a VFD fan
It all depends on the controller and how it's set up in the PID loop. PID stands for Proportional Integral and Derivative. Usually we only wet up the Proportional and Integral for HVAC applications. The Proportional value usually has a value of between 0-10. You usually start at 1 and continue to increase the value until the fan or pumps becomes unstable at or past the value you want. Once the value becomes unstable, take the proportional back down a bit until it slow down and is close to the set point.
Now adjust the Integral (which is in seconds) until you reach your set point and everything is stable. Then you should be good to go.
I'd say based on what I've seen that you should go from 0 to your setpoint in about 2 minutes.
RE: Time to change pressure in a VFD fan