The vibration levels at both motor fan speed are to be measured at the motor while the vibration levels at the blade pass frequency is to be measured at the fan shroud or stack.
Cooling tower fan blade balancing.
A likely structural natural frequency was identified at 310 cpm.
The air flow is produced by the fan which is driven by the motor either in direct drive or by gear speed reducer.
Thru balancing of the cooling tower fan we were able to reduce the 1x rpm fan vibration levels significantly from 72 mills to 2 5 mills at 330 rpm or from 19 mills to 0 6 mills at 240 rpm.
The air movement and control association intl inc s amca standard 204 balance quality and vibration levels for fans recognizes five different fan application categories bv 1 bv 2 bv 3 bv 4 and bv 5 for the required balancing grade during manufacturing of the fan see table.
We also offer shop services balancing motor armatures flywheels and crankshafts.
The latter would allow the gearbox to rock in a direction parallel to the input shaft.
Dynamic balancing of the cooling tower fan.
Here s the outside and inside.
The equipment we have balanced ranges from small blowers to the largest of cooling tower fans.
Frequencies present at cooling towers.
Where is the 0 65 in sec at 1200 cpm coming from.
The purpose of a cooling tower is removal of excess heat from water used in industrial processes to cool various systems.
Possible causes were unbalance due to dirty or damaged fan blades or a problem with the gearbox mounting structure.
No overall vibration level standards are offered by cti.
Fan speed motor speed blade pass frequency.
This document is intended to apply specifically to system vibration and mechanical balancing as related to fans and blowers.
I m balancing a fan with a speed of 348 rpm and the motor speed is 1800 rpm.
The principles presented however can be generally applied to many rotating components.
This document covers impellers while systems see amca standard 204 and ansi standard s2 19 are covered by air.
The fan was balanced to 0 5 mils but there was a high 0 65 in sec at 1200 cpm.
And the fan has three fiberglass blades.