Replacement of motorized actuater for damper

According to a calculator I got from the 'net, your 200kW fan will require only 84kW at 750 rpm (75% of 1000 rpm). Pretty good.

Anyone with a better calculator?

The information provided is not exhaustive to answer your question. However, the following information of generic nature may help you in finding the answer yourself.

Power (P) is directly proportional to Speed (N) to the power of "3".

Head (H) is directly proportional to Speed (N) to the power of "2".

Flow (Q) is directly proportional to Speed (N) to the power of "1".

Therefore,

P = K1 x N^3

H = K2 x N^2

Q = K3 x N

K1, K2, K3 = constants for given fan

As per information given the 25% reduction of speed should reduce the power consumption by 58%. However, the speed reduction will also reduce the static pressure of the fan. With reduced speed the operating point will shift. Therefore fan curves (flow vs.static pressure and flow vs.power) with load curve may be studied to find out the actual savings potential.

Greetings,

Check the load on the motor with the damper full open.

Then check the load on the fan at 75%.

The load placed on the motor is relative to the amount of work being done, damper closed = less air movement = less HP draw and less load.

The fans ability to move air is not linear to the speed, so 75% speed will actually be less than 75% of design flow rate.

Is the fan an axial or centrifugal? that will also have an effect on the performance curve.

The cost of a VFD and controls to drive is maybe more than energy savings, at least in the short term capital expenditure.

T.

You might look at the product of Type K damper drives as an alternative to you VFD option.