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Harbor Freight 2 hp dust collector questions

by Jim2020
posted 03-05-2021 09:01 PM


19 replies so far

View Bob5103's profile (online now)

Bob5103

210 posts in 1913 days


#1 posted 03-05-2021 09:14 PM

Is this what you mean?

When I modified mine it certainly appeared to stable, but just to be on the safe side I used 2 guy wires from the ceiling rafters to support the outboard side. I can’t answer your second question.

View Jim2020's profile

Jim2020

71 posts in 318 days


#2 posted 03-05-2021 09:21 PM

I can’t see for sure, but it looks like your attached the motor mount to the wall. Am I correct? I was thinking about removing it all together. Jim

View RClark's profile

RClark

126 posts in 3265 days


#3 posted 03-05-2021 10:11 PM

The motor/impeller assembly is the heaviest component of the whole HF DC set. The mounting bracket attached to the motor does two things that I can see:

—Carries the weight of the motor. The impeller shroud is supported by its own bracket. I don’t have an exact weight, but when I mounted mine, the motor was probably in excess of 40 pounds.

—The mount also absorbs the torque generated when the motor spins up. Without the motor being braced somehow, there will be significant twisting force between the motor and the impeller shroud.

Here’s a pic of mine mounted on a roll-around stand; it shows both mounting brackets, one fo rhe motor, one for the impeller shroud:

Bottom line: I think the motor mounting bracket is essential.

-- Ray

View Bob5103's profile (online now)

Bob5103

210 posts in 1913 days


#4 posted 03-05-2021 11:32 PM



I can t see for sure, but it looks like your attached the motor mount to the wall. Am I correct? I was thinking about removing it all together. Jim

- Jim2020


Yes, and I would not remove the mount, the assembly is too heavy.

View CWWoodworking's profile

CWWoodworking

1750 posts in 1258 days


#5 posted 03-06-2021 02:55 AM

I had a HF motor turned like that burn up in a month. Maybe it would have anyways.

HF is kind of a crap shoot.

View jtdon's profile

jtdon

32 posts in 1586 days


#6 posted 03-06-2021 10:54 AM

My HF DC has been mounted and running that way for 5 years.

View Jim2020's profile

Jim2020

71 posts in 318 days


#7 posted 03-06-2021 01:20 PM

JT: Do you mean it has been motor vertical without use of motor mount, or just motor vertical?

I also want input on my second question and the potential overload issue I asked. Is over spin the cause of overload, and will a parallel configuration solve that problem? Thanks to you who’ve answered so far. Jim

View Fred Hargis's profile

Fred Hargis

6978 posts in 3573 days


#8 posted 03-06-2021 01:49 PM

I assume the overload issue is created by causing the impeller to spin faster than the motor RPM, in effect causing the motor to run outside it s design parameters. Is that a correct assumption?

- Jim2020

I don’t think that’s the correct assumption. I believe (without having seen the nubs video) what you have is the first blower is cramming much more air into the second that it’s exceeding it’s (the second blower) ability to handle it. That slows the impeller down, much like the effect you feel when trying to run through water. That slowdown caused the motor to draw more current to get up to it’s stated speed. That overload heats things up, then melts things down. This is all guesswork on my part, I just can’t see a reason to try and hook up 2 of them. Someone else may have a better (or different) take on this and chime in.

-- Our village hasn't lost it's idiot, he was elected to congress.

View ibewjon's profile

ibewjon

2410 posts in 3873 days


#9 posted 03-06-2021 02:23 PM

I am always amused by the HF conversion discussion. It has been stated here that the cost of conversions is about the same as a new Jet or other machine. Plus the labor. I am very happy with my jet type collector. I did change to a pleated filter and add a vortex cone, but the time was minimal. I originally bought it before pleated filters existed. I would rather be working wood than rebuilding a DC from HF. Buying two machines to combine into one just doesn’t make much sense. Even more investment for a questionable result. Good luck.

View jamsomito's profile

jamsomito

657 posts in 1506 days


#10 posted 03-06-2021 05:19 PM

Adding 2 fans in series will double the pressure full closed and adding 2 fans in parallel will double the airflow full open. Actual results will depend on your system curve, or how much resistance there is in your ductwork.

The most dangerous situation with a fan is full open since they are usually designed for some restriction and power is dependent on the volume of air moved – with no restriction the fan will likely move too much air and the motor will likely be overloaded. So based on this, my gut is saying 2 fans in series wont necessarily give you the results you want in airflow, while 2 fans in parallel will bump your airflow but could create a dangerous situation with the motors.

Highly recommend double checking this consensus, but that’s my thought process.

View Jim2020's profile

Jim2020

71 posts in 318 days


#11 posted 03-06-2021 06:18 PM

Ibewjon: I happen to have two Harbor Freight dust collectors. I recently bought a cyclone, and think maybe one fan is a bit under powered.

If I were starting from scratch, I’d buy a 5 hp Clearview system, but I’m not. I’m just trying to maximize the performance with the equipment I have. I’m looking for system knowledge I don’t have, and real experience others here, may have.

jamsomito: Thanks for your input. This is just the info I’m looking for. I had the opposite view. It doesn’t sound like you’re entirely sure, if your are, correct me. In the mean time, maybe someone who knows for sure will chime in. Thanks agin. Jim

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jamsomito

657 posts in 1506 days


#12 posted 03-06-2021 07:55 PM

The only part of that I can’t back up scientifically off the top of my head is the increased power with flow, although I’m fairly certain that’s how it works. Think about a shop vac – while cleaning up it has a certain tone, but if it sticks the nozzle onto the floor or you put your hand over it, it gets louder and spins up faster. This is because if you remove the airflow, it’s not doing any “work;” you’re removing the load and it can spin up. It’s the same concept with dust collectors / fans.

I just don’t want you having confirmation bias and starting a shop fire because you listened to some random guy on the internet :). If I was about to do this, it’s something I’d make sure I have a thorough understanding of first, and how to monitor it after install to ensure nothing is overloaded. That’s all. I’m definitely curious to hear how it goes for you if you do try it out!

View nutsandbolts's profile

nutsandbolts

20 posts in 3127 days


#13 posted 03-06-2021 08:44 PM

http://www.jpthien.com/smf/index.php?topic=310.0

  • two fans in parallel will increase volume of air movement at the same static pressure (lift)
  • two fans in series will increase static pressure (lift)

If you are moving dust particles (sanding operation) you need sufficient velocity, to keep the dust airborne inside the piping. Airflow (cfm) = Area (cross sectional area – square feet) x Velocity (ft per minute). However, there is no free lunch. Velocity will be limited by head loss (friction). Joints add head loss (unions, tees, wyes). Flexible hose has more head loss. Smooth pipe has less head loss. Total length of straight piping adds to total head loss.

View nutsandbolts's profile

nutsandbolts

20 posts in 3127 days


#14 posted 03-06-2021 09:00 PM

Harbor Freight stock impeller is 10-inch diameter, and forward facing for the blades.
Rikon upgraded impeller is 12-inch diameter (fits inside the HF fan housing) and has rear facing blades.
The Rikon Impeller is an improvement. The Rikon impeller upgrade will draw more current, so the electrical circuit will need to be upgraded to a 20 amp breaker, and upgraded wiring to handle 20 amps of current.

Changing the impeller to the 12-inch Rikon impeller will increase static lift significantly (>30%). So, if you only run one woodworking machine at a time, you want more vacuum pressure (static lift). Who cares about vacuum pressure (static lift)? If you are trying to suck up chips and shavings (not dust), you need more vacuum pressure (static lift).

Bigger diameter piping (duct work) will increase airflow, cuz you are reducing the head loss. Just upsize your duct work diameter, so you can keep minimum airflow velocity, to keep dust airborne for the entire length of the piping.

So, two fans in parallel will boost your total airflow (more cfm). You can take advantage of the higher potential airflow, by going with large enough ductwork. Then, your next upgrade is to goto the 12-inch Rikon impellers, for both fans which are in parallel. The larger impeller, and switching to rear facing blades (Rikon) will boost vacuum pressure (static lift). Of course, upgrade to 20 amp circuits, a dedicated electrical circuit for EACH fan…so two separate 20 amp breakers, and upgraded electrical wiring for 20 amp circuits. No 90 degree fittings. Use wye fittings and use large radius sweep fittings. OR, only use 45 degree fittings, and in between 45 degree fittings use a stub of pipe at least 2 diameters long, between the 45 degree fittings…3 diameters long would be even better (short length of straight pipe)...cuz we want turbulent airflow to calm down, before encountering the next fitting.

View nutsandbolts's profile

nutsandbolts

20 posts in 3127 days


#15 posted 03-06-2021 09:09 PM

Why is a rear facing impeller better than a forward facing impeller? Rear facing impeller blades has no stall characteristics, has much better static efficiency (more bang for the buck, for static lift = vacuum power).

https://www.rs-online.com/designspark/fan-types-why-choose-a-backward-curved-centrufugal-fan

So, how come the HF fan uses a FORWARDS impeller blade? With zero resistance, you get huge CFM values.
Once you put some resistance in, like duct work, the CFM values bog down, the static lift values bog down.
Rikon Impeller upgrade is a good idea, if you also upgrade the electrical circuit (breaker and wiring)...and if you upgrade the diameter of your ductwork (pipe diameter) so you don’t overload the HF motor (bigger pipe means less current draw).

View jtdon's profile

jtdon

32 posts in 1586 days


#16 posted 03-06-2021 09:15 PM


JT: Do you mean it has been motor vertical without use of motor mount, or just motor vertical?

I also want input on my second question and the potential overload issue I asked. Is over spin the cause of overload, and will a parallel configuration solve that problem? Thanks to you who ve answered so far. Jim

- Jim2020

It’s mounted vertical with just the HF motor bracket holding it, never had any issues with it.

View Jim2020's profile

Jim2020

71 posts in 318 days


#17 posted 03-06-2021 09:21 PM

Actually what I have is a 2 HP unit with the 12” Rikon impeller, and a 1 HP (8 amp) unit with what appears to be a 9.5” rear facing impeller. Does this complicate matters? If I do this, I will put amp flow meters on both machines, so I can see how much juice each is drawing. The wiring and circuitry will be properly attended to. Jim

View clagwell's profile

clagwell

368 posts in 872 days


#18 posted 03-06-2021 09:22 PM



...and if you upgrade the diameter of your ductwork (pipe diameter) so you don t overload the HF motor (bigger pipe means less current draw).

- nutsandbolts


No….

Bigger pipe means more CFM. More CFM means more current:

-- Dave, Tippecanoe County, IN --- Is there a corollary to Beranek.s Law that applies to dust collection?

View jamsomito's profile

jamsomito

657 posts in 1506 days


#19 posted 03-06-2021 10:18 PM

Great chart, Dave.

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