HF Dust Collector Power Draw Question

[Brent Romero]

I assembled my HF dust collector today and for the moment I am having breaker trip issues.

I have #8 ga wire running to my shop which is rated for 45 amps. I plugged the unit into a dedicated 20amp circuit (12ga) which is located ~6ft from my breaker panel. The unit fires up and runs fine. If I allow the unit to run for several minutes and then shut it off and wait 30 seconds or so and turn it back on, it trips my breaker. The same thing repeated on several of my outlets. Their website states 20amp peak draw for the unit. I am thinking that I am exceeding the suggested load of 80% of the 20amp circuit (16amps) and this is what is causing the unit to trip. The weird thing in my mind is the 16ga power cord coming out of the unit....

Any thoughts?

Thanks

[Brad Schafer]

i have the HF unit and recently had trouble with a Long Ranger III getting really hot ... did a little non-scientific experimentation, and noticed the cord getting warm but not hot when direct-plugged. mine is on a 15A circuit, and i haven't ever had any breaker tripping.

i had the same thoughts as you about the 16ga cord, and really need to put an ammeter on this thing.

[Brent Romero]

Thanks. Then I may have a defective unit. I am running a Dayton compressor which is also on a dedicated circuit ~50ft away and have no problems. My breakers are old...so I will try replacing the breaker. Easy and worth a try.

[David Kumm]

Brent, are you running it with pipe off the impeller? Those units are meant to have some restriction so as to not overload. Dave

[Brent Romero]

David, I had one half of the Y plugged and the other half open. So there was not much restriction. BUT, the good news is I think I resolved my immediate issue. I ran down to the local Lowes and picked up a couple Square D QO style 20amp breakers and replaced two; one for my longest circuit run and one for my shortest, both of which were tripping. Eureka...problem solved. What I think is that the breakers are ~22yrs old and their ampacity load has decreased over time. Which I think is normal with age as well as normal tripping. What most don't realize is that each time a breaker trips the capacity decreases slightly...even without power being fed to the breaker. The trip mechanism is very mechanical and spring loaded.

The absence of restriction probably did not help the situation.

With that said, I do plan on running a dedicated 10ga (30amp rated wire) fused at 20amps to be able to handle the amp drop across the 35 or so feet.

Thanks

[Kevin Presutti]

Here is the code for #8 wire

#8 is rated at 40 amps but code only allows 80% capacity. 80% of 40 = 32 amps continuous

#8 Copper Wire is rated at 40 amps when you use Wire types TW, UF listed at 60 Degrees Celsius, 50amps at wire thats rated at 75 Degrees Celsius (TYPES RHW, THHW, THW, THWN, XHHW, USE, and ZW) and at 55 amps at 90 Degrees Celsius (TYPES TBS, SA, SIS, FEP, FEPB, MI, RHH, RHW-2, THHN, THHW, THW-2, THWN-2, USE-2, XHH, XHHW, XHHW-2, ZW-2. The degrees are what the insulation is rated at.

You may have a bad motor if you have a meter you could test the amp draw on a COLD start. then after it runs check and see what the motor draws on a HOT start. I have a small HF compressor and man does it extention cords. These chinese motors seem to require a large amount of juice to start. Best of luck!

[Michael W. Clark]

If this is on a dedicated circuit, why not run it 220V?
The 10ga wire sounds overkill for a 2hp motor. If I were doing that dedicated, I would do 220v with a 2pole 30A breaker. That would run most 5hp motors in case you wanted to upgrade.

[John Lifer]

Motor is 120v only, can't convert to 220V. So he's stuck with what he has. I'm running of 20A breaker, 12G wiring, no issue.

[Brent Romero]

I still go by my ole Square D Motor Data Calculator...which shows that 8THHN Cu is rated for 45 amps....but I do recall NEMA changing the ampacity ratings.

I will keep an eye on it...but I truly think I had a bad breaker.

Thanks

[Brent Romero]

This is all based on the circuit run length. At 50ft for a full load of 16 or so amps at full load you should move up to a 10ga wire. The ampacity drops as the run length increases.

The motor is straight 120v.

[Ron Natalie]

Ampacity doesn't drop technically (i.e., the wire is still rated to handle the current) with length, the problem is that you incur a voltage drop which may be unacceptable which increasing the conductor size will help with.
However 50 feet isn't going to make much of a drop on #12 at 16A. Low voltage definitely can cause starting problems in induction motors. What size motor are we talking about here?

[Brent Romero]

This is supposedly a 2hp motor. I did look in the owner's manual this morning and it suggests 10ga for a distance of 50ft.

[Chad Bender]

I've got no help with the breaker issues, just some emperical observations. I own the HF 2HP unit, and can run it and my craftsman table saw (21833, same as the rigid r4512, 1 3/4HP motor) on a single 20A breaker. I have to wait for the DC to spin up before turning on the TS. I've measured the current draw from the DC under a normal load to be only about 6A.

[Brent Romero]

Update: I was having less frequent breaker trips with the new breakers. Went from 1/3 trips at startup to 1/6. Contacted HF and they sent out a new motor. It def did the trick. Now I can finally use the darn thing. Their tech support and customer service is certainly a challenge. We shall see.....

Geaux Tigers!!