Retrofit Dust Collection Fan

Is there any percentage to up-sizing the impeller fan in an existing dust collector unit? May 15, 2012

In his book, Woodshop Dust Control, author Sandor Nagyszalanczy describes getting better effect from a small shop dust collector fan motor by retrofitting a larger impeller fan in the fan unit. I have also seen discussion of certain fan blade configurations being more efficient in terms of their ability to convey wood dust relative to others. The edition of the book that I have was published about ten years ago, and as far as I can tell through internet search, the resources that he recommended for retrofit fan blades no longer do business in such.

Does anyone know of any companies that will sell fan blades to retrofit in this manner? Are the bearings and blade widths on these fans of such standards that one could expect to purchase a fan impeller from one manufacturer and have it fit and function well in a DC manufactured by another manufacturer?

I specifically have a Grizzly G1029 with a 12" impeller and a 12 amp motor. I plan to disassemble it and use the fan to convey wood dust from my tools, through a pre-separation device, and on to a bag house of 6' long, 12" diameter felt sleeve filters. I have hoped that I might be able to switch out the 12" impeller for one of 14", and if such is available, one with a blade configuration that is more efficient than that which comes with the unit. Thanks in advance for any consideration and assistance.

Forum Responses
(Dust Collection and Safety Equipment Forum)
From contributor K:
The motor and fan are sized to fit from the factory. I wouldn't mess with it. The best thing you can do with an old blower is put it on top of a cyclone and increase the bag/filter volume. That will increase the air flow which is what you need.

From contributor G:
You will end up burning the motor out if you do this. It is designed to draw a certain amount of current and by putting on a larger fan impeller and trying to draw more air you will overheat the motor.

From the original questioner:

Thanks a million. I plan to do exactly that with the eBay available cyclone (I've been studying this for a while) and a bag house I plan to make. I thought from what had been printed in the book I cited, increasing the fan size might be another way to improve the rate of airflow. I guess I'll just let it be and save some money at the same time.

From contributor U:
I did this with a Cincinnati blower. You will need a fan curve to see whether or not your motor will handle the increased impeller size. Not sure if it is worth it cost wise as my 13" aluminum impeller was about $200. They can bore to whatever size shaft you have and so on. I doubt if Grizzly has a fan curve for your.

From the original questioner:
That's just what I needed to know. I don't know how well that would work with the Grizzly motor, but if it costs $200 just to buy the impeller, then it gets to where it would make more sense to just sell the DC I have and buy a good blower assembly than to buy a retrofit fan. As it is, I've had feedback from others who've at least described doing fine in a set-up like I've planned using the 2 HP motor with the 23" impeller that comes with it, so I think I'll just try it out first. If it works, great. If it proves inadequate, I'll reassemble the DC and sell it to replace the fan unit, since that's all I'll be using from the thing, anyway