Centrifugal fans?

Question

Speed-Torque Curve:

I shall be thankful if you kindly send me the method of plotting Speed-Torque step by step.

This is required for selection of the proper Motor.

Answer 1

*Pl. visit:
http://www.wittfan.de/english/techinf_centrifugal.html
*http://www.bloapco.com/fans/
http://www.engr.sjsu.edu/ndejong/Fan%20Performance%20and%20Selection.pdf

*Torque=9550*KW/RPM
Torque is in N-m.

*It is better to make a specification sheet and send it to manufacturer, they will send you the offer as per your requirements.Because of so many factors are to be considered, it is wise to float an inquiry.

Answer 2

You should usually be selecting the fan motor primarily based on horsepower and RPM, not torque. Usually the fan is first selected based on best efficiency for a particular volume and pressure. Then the RPM and horsepower are noted.
But if torque is what you really want - -

If you have the tabulated fan performance data from the fan manufacturer's catalog divide the horsepowers by the RPM and multiply by 5252 to get the torques in ft-pounds. Multiply that by 12 to get inch-pounds.

If you have the fan performance curve set , it will show, for each selected RPM one curve for pressure vs. volume and another curve for horsepower vs. volume. Using the math above, you can plot a torque vs. volume curve for fun because it will be of little other value to you.

Some fans have an increasing power curve in that horsepower increases directly as the volume increases for that RPM. You want to select your motor not to overload if the volume is actually higher than estimated. Such fans have forward curved rotors (The more common ones) and especially the radial bladed rotiors - the industrial blowers. Some other fans have backward curved non -overloading rotor designs. The horsepower will peak and drop off. You can select the motor to be just higher than that peak cataloged horsepower. These fan designs are usually higher efficiency, but higher speed than the 'squirrel cage" forward curved onse and much higher efficiencies than the radial.

A torque calculaton may be necessary for motor selection only if you have a large fan with a heavy rotor- a high WR^2 momentof inertia. Then you will also need the motor torque curve. These are special considerations - not common.

Answer 3

the force which acts on a body which is moving about a fixed point so as to deflect that body from its path