Centrifugal blower input power vs speed

[edison123]

I hope this is the right forum for centrifugal fans.

Below is the nameplate of a centrifugal blower motor.

Given the centrifugal fan affinity cube law, how come the power is 1.1/1.27/1.1 KW at 2885/3480/3500 RPM ?

Muthu

http://www.edison.co.in

 

[LittleInch]

Because its the motor data plate.

The motor vendor doesnt know what use its going to be put to.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[edison123]

The whole main motor and the blower is a complete Siemens package.

Muthu

http://www.edison.co.in

 

[LittleInch]

It's still made up of a standard motor and a blower.

The same motor will be used in multiple different packages/ uses and they are not going to do a specific motor data plate just for one package.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[TiCl4]

Edison123,

The blower is required to put nameplate motor designed power draw "capacity". This has nothing to do with the fan, pump, or whatever else is connected to the motor.

The power draw at different Hz and run speeds (differnt pole configurations) is the same (roughly) because this is a 1.5 HP motor. The wiring is designed to handle only a certain power load.

However, if you run that motor with no load attached, it's not going to draw 1.5 HP. Design power =/= actual power draw.

 

[LittleInch]

I can only guess that they sized the motor based on the highest possible speed of 3500 and therefore any lower speed is lower power demand.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.