# How to get HF 20A Dust Collector working at 15A or less?



## JavaGeek (Feb 2, 2010)

How can I get a 20 amp dust collector with an induction motor to only use 15 amps? Also, how can I measure how much current I am using?

I ordered a heavy-duty speed control  from MLCS Had 2 questions:

Is there any reason this shouldn't be used with an induction motor (I know nothing about induction motors...is it troublesome to throttle their current?)
How can I figure out how much current it is using?

I have a kill-a-watt which I use around the house to measure computer power consumption, but it's only rated for 15A. I don't want to set the DC too high and burn it out. The company doesn't appear to sell anything rated higher. Does anyone know of any tools or techniques to measure power consumption?


I am trying to configure a router with a dust collector in a porter cable omnijig. I am using a switch so that the DC turns on and off when I turn on/off my router.

I tried at first using my trusty shop vac, but the jig is just too large and is designed for an actual dust collector and the vac couldn't suck up the debris, so I bought the Harbor Freight 2HP Dust Collector after hearing wonderful reviews about it. 

Unfortunately, it uses up to 20amps and every switch I could find but the ivac $120+ wireless combo is only rated for 15. I ruined a crappy iSocket switch and bough the iVac switch and trigger the built-in breaker each time. (it's the first time I've ever complained about a harbor freight tool having TOO MUCH power).

I can't afford to return or discard the DC and it's quite a pain to turn on and off manually because 9 times out of 10, I forget to turn it on and leave a huge mess. Any advice would be greatly appreciated.

Thanks in advance!!!
Steven


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## knotscott (Nov 8, 2007)

That might be tough....kind of like asking how you can be shorter. Maybe some of the electrical gurus will have a trick for you, but I sure don't know how it could be done without switching to 220v, which I don't think the HF DC unit can do.


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## Brink (Nov 22, 2010)

A/C induction motors speed is controlled by 1) the number of poles wired into the motor, and 2) the frequency of the a/c current supplied. 

I don't think the speed controller you have will work on this motor. It'll work well on a motor with brushes.

To check the current to the DC, a conductor to the motor needs to be isolated, then a clamp on ammeter, such as an Amprobe used to read the current.


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## woodnthings (Jan 24, 2009)

*2 cans 'O worms here*

The 20 amp rating is all you can get out of a 12 ga wired duplex household 20 amp rated outlet. Period. You need all those amps to start the motor, but then it will draw less current as it runs. Sorry, that's the Law of Electrics. 
If you want to control it remotely there are several ways. A switch on a long cord for on/off, switch also rated for 20 amps. Second, a Dust Collector remote controlled switch from Penn State Industries: http://www.pennstateind.com/store/LR110-3.html


2nd can 'O worms... The router current rating usually 12.8 to 15 amps is all a 15 amp household outlet is rated with 14 ga wire can carry. You can not add a shop vac to that circuit and have it all come on simultaneously. It will trip the breaker. The router and shop vac can be combined on one switch on a 20 amp circuit. However they should be switch on one at a time to avoid tripping the breaker and or starting on limited current. The best solution is to have 2 separate dedicated circuits for each tool. That's what I have and it works fine. Proper electrical shop wiring is just as important as having the proper tool for the job at hand. JMO.  bill

All my shop 115 V. outlets are rated at 20 amps.


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## dbhost (Jan 28, 2008)

If you want the HF 2HP dust collector to work on a 15A circuit, you are going to need to swap the motor over to one that draws less than 15 amps...

This would be a great time and reason to pull in a sub panel so you can have the 20 amp circuit you need for the dust collector...


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## TimPa (Jan 27, 2010)

you could install a 20a rated relay to control the dust collector motor, with a 120vac coil controlled by your remote receiver. once a motor is built, it is impossible to change the current rating without a motor rewire. as far as i know.


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## mikeintexas (Oct 25, 2011)

Just thought I'd add this. I just bought the HF DC in question. I put it together but it's not attached to anything yet (not doing any work).
The sole outlet in my garage is a 15A, GFCI outlet. I can turn the DC on and off just fine without blowing the breaker or tripping the GFCI outlet. I know I will have a problem trying to run a table saw AND the DC on the same outlet. Probably will run an extension cord from inside the house for that.

Possibly the OPs breaker for that outlet is bad?


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## dbhost (Jan 28, 2008)

I am curious. Why measure power consumption? It's an electric motor, when not in use, unplug it. No leeching effect... I guess if you HAD to know how much volts / amps etc... it pulls at any given time, use an inductive multimeter to gather that data.

As far as remote switching is concerned, that isn't the easiest with the 20amp DCs as most remote switches are reated to 15 amps or less. The only one I know that is rated to 20 amps is the Penn State Long Ranger 110V Amazon.com: PSI Woodworking LR110-3 110-Volt Long Ranger Dust Collector Switch: Home Improvement which retails for around $58.00.


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## JavaGeek (Feb 2, 2010)

*Rationale for measuring power consumption*

First of all, thanks for the insights guys. I don't like what you have to say, but that's life, I guess  Shame on me for not doing more research before buying.

Fortunately, the dust collector is set up 4 feet from a breaker, so it should be reasonable to have an electrician add another circuit.

The reason I wanted to measure the current was just to see precisely how much it's consuming...under the theory a speed control would work. Apparently, it won't  Oh well, I'm out $35 if I can't find another use for the speed throttler. I'd like to use it on my home-center grade Porter Cable stationary sander, but I'm not sure if it's an induction motor (it's hidden in the casing).

If a speed control worked, I could tune it to 14a or so w/o trial and error of seeing if the iVac switch breaker flips. 

Swapping out the engine seems complicated. It's a good thing this is a hobby and not something I need to do to earn a living, so I can have long delays.

Veering off course...

It's ironic that I went with 2HP HF because it was like $100 cheaper than the next cheapest 1.5HP, but more powerful than their 1HP mini dust collector, which just couldn't handle an omnijig. I will end up spending a few hundred dollars getting this working. I had to buy a UPS for the router, cable modem, and home server, which is on the same circuit (Comcast installs internet, phone, and AV equipment in the basement) because it flipped the breaker a few times and angered the Mrs who was working from home when it took 45 minutes to get the internet connection back up. I am out $35 for the damaged cheapo iSocket switch, out $45 for the 15a rated iVac switch...which I can probably easily find a use for...and now I am either hiring an electrician or spending a few hundred on the 20a rated wireless iVacPro auto-switch with the hope the tool + DC doesn't consume the total 20a needed to overload the breaker....or installing a 2nd motor...because the HF was too powerful!

Lesson learned. Check tool ratings. I guess don't take electricity for granted either?...don't just assume you can plug something in an it'll work.


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## dbhost (Jan 28, 2008)

Assuming your computer setup you mention, and your UID being JavaGeek, I am guessing you are in the IT field... If you do system planning or administration, I can have you think of it thusly...

Would you order a new rack with Power Distribution Units not knowing what voltages or amperages your servers use?

For me, and probably a mess of others here, I have had to "rig something up" to make it all work. The DC gets connected to the 110V circuit that feeds the washing machine. It annoys my wife that she can't do laundry when I am running the DC, but it's a temporary trade off, and then my other machines go one machine at a time, connected to the single 15 amp circuit in the garage / shop...

Long term and ideal would be to run a sub panel with at LEAST 60 amps, 3 20 amp circuits. separate from the existing power. 1 circuit for dust collection, 1 for the power tools, and 1 for HVAC.


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## woodnthings (Jan 24, 2009)

*Did you read the MLCS specs?*



JavaGeek said:


> How can I get a 20 amp dust collector with an induction motor to only use 15 amps? Also, how can I measure how much current I am using?
> 
> I ordered a heavy-duty speed control  from MLCS Had 2 questions:
> 
> ...


You can't use a variable speed control on an induction motor, only those with AC/DC types, IE brushes....

Quote from MLCS:
• Works with most routers 3-1/4 HP or less • 120V
• Give your router a feature only available on expensive routers
• Easy to use- Simply plug in speed control and plug your router into the speed control- turn dial slowly for best results. (Speed control has a clip that can be worn on your belt, hung on wall, or left loose).
• Dust Cover Included (not shown in photo)
*NOTE: Will not work with soft start or variable speed routers. Will not work with "AC capacitor start induction" type motors.*


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## JavaGeek (Feb 2, 2010)

woodnthings said:


> You can't use a variable speed control on
> *NOTE: Will not work with soft start or variable speed routers. Will not work with "AC capacitor start induction" type motors.*


Ouch, that stings  I missed that last point. However, this is another lesson for next time. I'll have to be more careful reading specs.


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## dbhost (Jan 28, 2008)

It's all good. Think of it this way. Now you have a good excuse to put in a proper sub panel ....


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## Wackadoo (Nov 1, 2011)

JavaGeek said:


> How can I get a 20 amp dust collector with an induction motor to only use 15 amps?


Air weighs 1 pound per 13 cubic feet. 
Reduce the airflow but watch out that the motor stays properly cooled.


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## rrich (Jun 24, 2009)

Making your 20 ampere dust collector operate on less than 20 amperes is easy. Just rewire the dust collector to run on 240 Volts. Then your 20 ampere dust collector will only draw 10 amperes.

I realize that is not the answer that you wanted to hear, but it is an answer to your question.

If the outlet is but 4 feet from the breaker panel it may be easier for you to change the wire size to 12 gauge and swap the breaker for a 20 Amp breaker. It's a 30 minute job if you don't have to go inside the wall to route the larger wire.


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## tvman44 (Dec 8, 2011)

My HF DC is not hooked up to anything yet but the motor draws 14.75 amps running with no hose or anything connected to the input. Start up current will be almost double that.


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## Dierte (May 26, 2011)

After reading this and finally buying one here's the deal.
1. This unit isn't a 20amp unit. Look at the cord end. If it was over 15 amps the cord end would be different.
2. Of course it will draw alot more than 20amps on start up. Look at your air conditioner. It probably has a FLA rating of close to 70amps, but its probably on a double pole 30amp breaker. In an ideal situation I would run a dedicated circuit for the dc.

Sorry that you tried to save a dime and ended up spending a dollar w/ your dc setup. You'll get there eventually.


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