[Woodworkers] Best laid plans......

[Dave Heitstuman]

Richard, and all
In regards to you motor comment.  In theory what you are saying may hold some water.  However for the typical hobbyist application I doubt that it is a concern.
Some of this is not going to probably sound all professional mainly because I don’t know (or care) about all the engineering terms that apply I just go by what I have experienced.
First I have no firsthand knowledge of the HF DC.
Second I am going to assume that the motor does have an internal cooling fan.
I do VFD startups on fans and pumps used in the HVAC industry.  Pumps need to have a set minimum speed of 18hz to move enough air through them to keep the motor cool.  Fans can be set lower as long as the motor is within the airstream and the airflow through the HVAC equipment is sufficient to cool the motor.  If not they get set to 18hz.  Point being the motor cools itself with the internal fan.
Next a freewheeling fan with no duct work restriction will draw more amps than one with restriction.  This leads to a higher amp draw which increases the motor temp which is going to eventually trip the overloads.
Assuming that the new impellor is balanced and within a few ounces of weight of the original and not causing undue stress on the motor shaft; assuming the normal DC usage of reduced size to 4” at the tools and the final assumption that the motor has an internal fan I don’t see a reason to be concerned.  Now there could be some other dynamics in play such as what it takes to spin the larger diameter impeller but again for hobbyist usage I doubt that there would be enough extra wear and tear on the motor to warrant it being of any concern.

And then of course we have the internet ☺  The HF DC gets a lot of press on the woodworking forums as being one of those diamond in the rough tools.  This is the first time I have heard about replacing the impellor but if the info is out there and no one has pointed out anything bad happening why not?  If I was in the market for a shall we say more cost effective DC that I could start with and improve as the dollars were there I would probably have to seriously consider this route.

Just my 2 cents worth

2Dave


From: Woodworkers [mailto:woodworkers-bounces at lists.sawdusters.org] On Behalf Of Richard Allen via Woodworkers
Sent: Friday, February 23, 2018 6:40 AM
To: A place where woodworkers talk about woodworking
Cc: Richard Allen
Subject: Re: [Woodworkers] Best laid plans......

The motor run at near max HP all the time.  Putting a larger blower on a motor will over power the motor.  You could cool the motor or expect the motor to fail fairly quickly.  If you get a bigger blower you will get a bigger motor (either at the start or after the motor dies).

Another way to increase the air flow is to increase the airflow through the filter.  Increase the surface area of the filters.  Please note that a canister filter provides a LOT more surface area in the same size footprint.  Factories have “Bag rooms” for their dust collection.  You could just exit the dust outside for max air flow.

The last area where you can increase air flow is on the input side.  Big pipe will increase air flow.  The down side of large pipe is a decrease in static pressure.  The ability to lift and move is with high static pressure.  A Shop Vac can lift a cannon ball but it can’t collect fine saw dust from a foot away.  Whereas an 8” pipe connected to a large DC can collect fine sawdust from 3’ away.

Recap:

Bigger blower (fan) needs a bigger motor

More filter increases airflow but bigger filters cost more.

Bigger pipes move more air but cant lift heavy loads.  And big pipe cost more.



On Feb 23, 2018, at 8:25 AM, Larry Works via Woodworkers <woodworkers at lists.sawdusters.org<mailto:woodworkers at lists.sawdusters.org>> wrote:
I assume the larger diameter moves a significant amount of air. What is the impact on the motor, particularly as it starts and then as it is stressed when it starts moving large amounts of sawdust?  I have the HF and feel like I need to move more air myself.

On Feb 23, 2018 7:25 AM, "Tom Lovelace via Woodworkers" <woodworkers at lists.sawdusters.org<mailto:woodworkers at lists.sawdusters.org>> wrote:
I bought the Harbor Freight dust collector wit the idea of upgrading it.
Ordered and received a Wynn filter. Haven’t mounted it yet.
Ordered an impeller upgrade from Rikon.
The one used on the Rikon Model 60-200 is a 12 inch diameter unit that is a drop-in swap for the HF collector.
The HF impeller is only a 9.75 inch diameter unit
Unfortunately, Rikon says the new impeller is on back-order. Won’t be in until JUNE !!
Seems far too many folks are buying this unit as an upgrade for their HF systems.
O well.leaves me more time to work in the shop.
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