TeeAr
Mechanical
- Feb 27, 2010
- 24
Dear all,
Hope somebody can help me to clairfy this topic.
I have seen some threads about this topic, but none of them is answering my next question.
I have measured the air flow, rpm and absorbed power of a three phase axial fan at two different fan speed – delta and star connection.
I will call 1 and 2 this two conditions..
What puzzles me is, if I consider affinity laws
- equation (air flow 1/air flow 2) = (n1/n2) is respected. The two ratios are practically identical.
- equation (absorbed power 1/ absorbed power 2) = (n1/n2)^3 is not respected. (the power is the total absorbed power)
There is a large difference between the two ratios.
Please, is there something I am missing or is it due to a wrong measurement ?
Many thanks
Hope somebody can help me to clairfy this topic.
I have seen some threads about this topic, but none of them is answering my next question.
I have measured the air flow, rpm and absorbed power of a three phase axial fan at two different fan speed – delta and star connection.
I will call 1 and 2 this two conditions..
What puzzles me is, if I consider affinity laws
- equation (air flow 1/air flow 2) = (n1/n2) is respected. The two ratios are practically identical.
- equation (absorbed power 1/ absorbed power 2) = (n1/n2)^3 is not respected. (the power is the total absorbed power)
There is a large difference between the two ratios.
Please, is there something I am missing or is it due to a wrong measurement ?
Many thanks