Noise level of Bill Pentz 5hp Cyclone

[Dale Critchlow]

I am considering upgrading my homebuilt cyclone from a 1 1/2hp blower to 5hp using Bill Pentz's "budget blower" design. The bearings are failing on the present motor.

I would be interested in any noise measurements which people have on this unit.

Also, in order to understand the numbers, the measurement conditions are useful. From how far away were the measurements made? What instrument was used? Was the cyclone connected to the ductwork and filters? Was there a muffler in the system? etc.

Thanks,

Dale Critchlow

[Allan Johanson]

Hi Dale,

My shop has a 9 foot ceiling with the cyclone in the corner. Standing about 10 feet away, with the Radio Shack analog db meter held at ear height with my filter enclosure in place (no specific muffler, but the filter enclosure reduced the db about 4-5 points when compared to no enclosure).

10' away it's 84db. 14' away, it's 82db. 18' away it's 80db.

This was with ductwork in place and standing beside the tablesaw which had the blast gate open. Whether the blast gate was open or closed it didn't make any noticable difference in the noise level. The sound changed its tone, but the overall db level didn't change.

Cheers,

Allan

P.S. Here is a pic of the cyclone with the filter box (I think this link might work - not sure):

[Bill Lewis]

Is the 5 hp motor the same RPM as the 1.5 hp motor? If so, this isn't really an upgrade, i.e. it won't move any more (air) than the current setup. Now if you are also changing to a larger diameter blower that's a whole 'nuther story. Of course you consider a moter that works vs. a dead motor as an upgrade, I'll buy that!

[Bart Leetch]

Is the 5 hp motor the same RPM as the 1.5 hp motor? If so, this isn't really an upgrade, i.e. it won't move any more (air) than the current setup. Now if you are also changing to a larger diameter blower that's a whole 'nuther story. Of course you consider a moter that works vs. a dead motor as an upgrade, I'll buy that!

Its is quite a upgrade considering the impeller is 14" instead of 11.5" or 12".

[Ken Garlock]

Hi Dale. To see any improvement you must replace the entire blower assembly: motor, impeller, and housing. So long as your current motor is now running at its rated RPM, you could a same RPM 100 HP motor in its place, and still have the same performance, no improvment.

I built the Pentz kit offered at the time by Mr. Ecoles. I measure it with a Radio Shack audio meter and got 103 db with no ducting attached. I wrapped the output duct with fiberglass duct insulation, and attached it to a filter box containing two filters working in parallel. Then the noise dropped to about 92 db. After putting all the input pipe in place(6"PVC), the noise dropped to the below 85 db.

The cyclone will not be the noise problem in your shop. My 8" jointer cranks out a healthy 102 DB when measured at the operating position.

[Dale Critchlow]

Guys, thanks for the responses.

Ken, Bill: If I go to 5hp, I will use the 14" Sheldon impeller and enclosure Bill Pentz recommends for his budget blower design. I think it is the same design as the Ecole's system Ken has. Both my present motor and the proposed 5hp motor are 3450rpm. If I remember correctly, my present impeller is 12".

Yes Bart, it is quite an upgrade. I was trying to find a 3hp solution, but haven't succeeded. The cost is about the same since Bill Pentz has done such a good job of laying the groundwork for the 5hp design. The only down- side I see with the 5hp approach is the noise. That is the reason I was asking about the noise measurements.

My present system is in a closet. I measured about 75db with the closet doors open and with the filters and ductwork connected. The motor/blower assembly is mounted higher than top of the closet doors, so that may attenuate the noise somewhat. (With the closet doors closed the noise was a few db lower.) I used a Radio Shack meter and was standing about 8' away.

So Alan's and Ken's measurements on the 5hp systems are about 6 to 10db higher (or about 2X to 3X louder) than my present system. I could probably get a few db improvement with a muffler if needed.


Dale Critchlow

[Bill Lewis]

Since you are increasing the size of the impeller from your existing 12" to a 14" you will have a performance gain, and therefore an upgrade to your existing system.

This wasn't directly indicated in your original post. My point was that if you kept the same impeller size, and same motor RPM then by increasing the HP of the motor there would be no improvement at all to your system perfromance.

Ok, noise levels. Well I don't think anyone can give you really good numbers on how much increase in noise you'll get from the 3 hp vs. the 5 hp motor. Or from the 1.5 hp to the 5 hp for that matter. If your bearings are really going bad, it might even be quieter. Actually my point is that there are too many factors to consider. I've stood directly next to some big electric motors, and you can hardly tell if they are running they are so quiet. Of course these were on board one of our submarines. Now if you could find someone who has the exact same motor, impeller, and cyclone that could take some measurements, you have some really close numbers.