Working on a blower which is directly coupled with motor

[adilakbar]

Hi everyone,

I am mechanical engineer by profession. I need little help from you guys.
I am working on a blower which is directly coupled with motor. Now I am plannig to shift it to Belt Drive.
Purpose behind doing this was that we need to save power and avoid alignment issues related to it.
I have done all calculation for it summary of it is below

Design Summary

Motor Power (hp) 121
Service Factor 1.3
Design Power (hp) 157
Motor rpm 1480
Required blower rpm 700
Speed Ratio 2.11
Motor Pulley Dia (in) 7.1
Blower Pulley Dia (in) 14.9
Belt Length (in) 95
Center Distance (in) 30.20
Number of belts 10

After doing all that calculation I am stuck in one thing how much power is saved by doing this and do we need to install lower rating motor in it when we shift to belt drive kindly help in this regard.
In simple words how much power is saved when motor rpm are reduced from 1480 to output rpm 700.

Regards
Adil Akbar

 

[Travis_King]

That depends on your specific blower. It should have a curve.

BTW, the motor rpm is still 1480, the blower rpm is what is changing.

 

[adilakbar]

Can you explain which curve are you talking about. I don't have any curve of that blower.

 

[Chronos]

The nice thing about belt drives is they require no lubrication. You can adjust pulley sizes to achieve the desired RPM. You lose a small amount of torque due to friction losses, but, not enough to be of concern. Driving a blower coupled directly to the motor shaft is generally frowned upon.

 

[Travis_King]

The fan manufacturer will have a performance curve for your specific model of blower. I'd contact the manufacturer if you don't have that info.