Fan and Blowers Capacity

Upto a certain extent by changing the RPM and then you have to get a new one.

increasing motor PRM means more power , it means motor ovre loading ,over heating, dinamicaly unbalance , motor and blower vibration, electric contactors tripping .

Its not advised to channge anything of original designed parameters.

Dear Friend,

You cannot increase the capacity of the blower, kindly check it out whether its function is upto the level quaranteed by the manufacturer if it is ok, there is no other way, you have to go for a new one, mail me the specifications of your blower to eetatransmissions@yahoo.co.in , so that i will be able to guide you whether to go for a new one

i got a york AHU unit model ysm 40 x 70 (6R 12F) with air flow 6000 l/s and need to change to 7000 l/s and now what should i do.

Start by getting on the phone to <...york...>.

by increasing speed possible to increase flow, but not efficient way, it will result in fast wear of casing as well impeller.
i have experienced it, better go with new one.

You asked a very good question, and I agree that of course there are ways to do what you are thinking about. Yes, there are ramifications to changing any design. But you might very well be able to live with those tradeoffs, such as reduced life, vibration, etc. I DO hope you pursue your line of thinking further. If you are spending your own money I'm sure you will..

For instance, if you have a bunch of blowers that were recently installed in a plant and are good for 10 years but they just don't keep things cool enough, would you throw them all away in THIS economy if you could instead run them 20% faster and replace them in 9 years? 5 years? 1 year? NO! You'd pay right up to the cost of parts and labor to speed them up before you would just throw them away - anything to defer expenses yet maintain operations until the economy picks up or at least until next year..

If I were you I would ask your question with more detail, so you get both a better answer and a better understanding of the tradeoffs.

Survive to thrive!

Manufactures of commercial fans and blowers publish performance curves for them. It shows things like how much power a fan needs to turn a certain RPM and what the resulting air flow will be. Obviously there are other factors like air density and humidity.

These curves will show you if the specific fan or blower is operating at its peak capacity in its current application. If it is not, it can reliably be sped up to provide more output. Another way to provide more output is to increase the density of the feed air or possibly decrease the static pressure on the outlet side.

Once you get the fan curve and understand it (not difficult for a technical person) you will be able to answer your question for sure.

Yes, you can increase fan or blower capacity but it depends how much the existing motor can exert extra power for a certain flow rate required, you can do this by ratio and proportion (power against the flow) by using formula of affinity laws of fans. If the motor extra power is enough to deliver the required flow rate, then you can change (increase) the motor pulley size in order to increase rpm of the blower if the motor pulley is smaller than the blower pulley size. You can change the blower pulley size if it the smaller than the motor pulley size.

If the the existing motor has already exerted to its max. rated current load, there is no other way but to change or upgrade the motor or change the entire unit.

graysurpa