g.mccormick
Lifetime Supporting Member
We are going to be putting in place a large radiator for cooling water. The radiator is going to have some number of fans on it. I don't yet know number of or hp rating of these fans. Lets assume 5 5hp motors. I will control the fans to control the outlet temperature of the coolant leaving the radiator. As load increases, fans will need to be brought online. As demand lessens, they will be shutdown.
I'm pretty sure I don't want to put a vfd on ever motor due to cost, complexity, etc. I'm thinking of either 1 vfd running the 5 motors (with individual contactors and overloads), or just running the motors across the line and controlling the contactors based on demand.
Q1. What would be your preferences?
A. 5 vfds for 5 motors
B. 1 vfd and 5 contactors/overloads
C. 5 contactors/overloads
Q2. If using the vfd, I would plan to bring on the motors in stages, would you expect anything funny to happen to the vfd when throwing a motor load such as this on it? Obviously the higher the freq. when the next motor is called for, the higher the loads since this is a vt fan application.
Q3. I'm assuming that I'd need to oversize the drive. If it is going to be 5 5hp motors, I'd probably need to go larger than 25hp drive correct? How oversize to go? I'm thinking 125% based off wild *** guessing.
Anyone with insite?
Thanks
Garrett
I'm pretty sure I don't want to put a vfd on ever motor due to cost, complexity, etc. I'm thinking of either 1 vfd running the 5 motors (with individual contactors and overloads), or just running the motors across the line and controlling the contactors based on demand.
Q1. What would be your preferences?
A. 5 vfds for 5 motors
B. 1 vfd and 5 contactors/overloads
C. 5 contactors/overloads
Q2. If using the vfd, I would plan to bring on the motors in stages, would you expect anything funny to happen to the vfd when throwing a motor load such as this on it? Obviously the higher the freq. when the next motor is called for, the higher the loads since this is a vt fan application.
Q3. I'm assuming that I'd need to oversize the drive. If it is going to be 5 5hp motors, I'd probably need to go larger than 25hp drive correct? How oversize to go? I'm thinking 125% based off wild *** guessing.
Anyone with insite?
Thanks
Garrett