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2800W 110V Jackhammer, How?

crabjoe

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Jul 15, 2012
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Ceciltucky, MD
I've been looking at electric jackhammers and I seem seeing these Chinese ones rated at 2200+ watts, but with a 110V plug. How is that possible? Even if one were to use a 20amp receptacle, there's not 2800 watts available.
 
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iron block

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Jun 22, 2015
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Is it something like this one? http://www.amazon.com/XtremepowerUS-2200Watt-Electric-Demolition-Concrete/dp/B00IO3Z5MS

According to one of the reviews, that "2200 Watt" unit actually draws 12 Amps when running on a light load. That would be about 1400 watts. Seems more believable for a 120 volt tool.

The "2200" watt rating seems to be calculated from the motor starting current, which the same reviewer measured at about 21 Amps for a brief period -- like the period during which the house lights dim when you hit the trigger to start the drill :)

Seems that they are using the same rating approach as those vastly overrated household vacuum cleaners, that used to boast about "peak horsepower" until the UL and CSA put a stop to it.

Your 15A outlet should be fine.
 

kctyphoon

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I have one of the cheap jackhammer.. I bought it to do French drains in my basement (still haven't done it) but I did bring it to work a few times just to try out.. Great item for the money IMO.. Came in a metal case with 2 bits, gloves & glasses, and extra brushes.. As long as you fill it with oil and change it after you give it some heavy use, it should be fine..
 
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crabjoe

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Jul 15, 2012
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197
Location
Ceciltucky, MD
Is it something like this one? http://www.amazon.com/XtremepowerUS-2200Watt-Electric-Demolition-Concrete/dp/B00IO3Z5MS

According to one of the reviews, that "2200 Watt" unit actually draws 12 Amps when running on a light load. That would be about 1400 watts. Seems more believable for a 120 volt tool.

The "2200" watt rating seems to be calculated from the motor starting current, which the same reviewer measured at about 21 Amps for a brief period -- like the period during which the house lights dim when you hit the trigger to start the drill :)

Seems that they are using the same rating approach as those vastly overrated household vacuum cleaners, that used to boast about "peak horsepower" until the UL and CSA put a stop to it.

Your 15A outlet should be fine.

Yup, That and this one http://www.amazon.com/dp/B00R8PAM0S/?tag=atomicindus08-20 .

My understanding is that even the 2800 rated one has a 15 amp plug.

I guess if they're counting starting amps then 2800 watts makes sense...

Thanks All!!
 

ddawg16

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S. California
Reminds me of the pickle Sears got into over the 'peak hp' rating on some of it's vacuums....or something like that.
 
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rlitman

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Long Island
The "2200" watt rating seems to be calculated from the motor starting current, which the same reviewer measured at about 21 Amps for a brief period -- like the period during which the house lights dim when you hit the trigger to start the drill :)

Seems that they are using the same rating approach as those vastly overrated household vacuum cleaners, that used to boast about "peak horsepower" until the UL and CSA put a stop to it.

Actually, the brake to locked rotor horsepower ratings of vacuums is a little higher than you'd calculate using the measurement of inrush current, but for the most part, you get the idea. It's an effectively "imaginary" number with no application to the end-user.

.... could be some one is making some weird calculation with PeakVoltage instead of RMS.... it is possible.... 120V 60HZ you normally see is RMS voltage. Any one who's a real electrical engineer should be able to confirm this. I am just an imaginary one.

http://learningaboutelectronics.com/Articles/Voltage-rms-calculator.php#peak

2800W/170PV = 16.5AMP....

No, because watts do not work that way.

It might do it for a millisecond.

Yes, I'm aware that your answer was not completely serious, but here's a serious response:

You'd be surprised about how much current you can pull from a 20A breaker, and for how long.
Also, I've never seen a breaker that can interrupt a current in a millisecond.
The fastest reaction time I've seen is around 1 cycle, which at 60 hz is around 17 milliseconds. And to trip a breaker that fast, you'd need to exceed the magnetic threshold of the breaker, which looking at the trip curve for Square D QO breakers, is between 9 and 22 times the nameplate rating. i.e. you'd have to exceed AT LEAST 180A to trip on the magnetic.
On the thermal detection, at 30A draw (1.5x the nameplate rating of a 20A breaker), a QO breaker will take between 30 and 180 seconds to trip.
 

FordTruckWench

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Jan 8, 2015
Messages
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California
I guess if they're counting starting amps then 2800 watts makes sense...

The 2800 watts here likely has nothing to do with electrical watts. It is probably a measure of the mechanic energy of the hammer blows.

The unit "watt" is equivalent to kg * m^2 / (s^3). So, given the mass of the hammer (in kg), the distance it moves (in m), and the time interval for which it moves (in s), you can compute a number in watts.
 
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