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Old 08-26-2012, 03:58 PM   #31
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Maybe I'm confused about a 5HP motor.


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Originally Posted by Bugman1400

I think I lost sight of what stickboy was saying about the air compressors and concentrated on motor theory. I was not aware of the fake HP story. Since I design substations, 5HP motor to me is a 5HP motor unless, it has a higher than 1.0SF. Luckily, kbsparky's link provided a great condensed version. I actually learned something about non-commercial air compressor loads.
I'm guilty of the same thing. If you say it's a 5 HP then it's a 5 HP. As Petey keeps reminding me, some of these motors are falsely advertised. You have to look at the nameplate.

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Old 08-26-2012, 06:05 PM   #32
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Maybe I'm confused about a 5HP motor.


Very NICE house StickBoy!! HOLY CROWN MOLDING!!!

I did my kitchen and it came out perfect but, it was minimal and I had to stand on my head backwards to get the dangle of the angle....whew!! Good Work!!! Nice Indeed!! Guess I shouldn't have shown my wife the pics...now she's getting ideasand I'm too old for that $@%t
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Old 08-26-2012, 06:45 PM   #33
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Maybe I'm confused about a 5HP motor.


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Very NICE house StickBoy!! HOLY CROWN MOLDING!!!

I did my kitchen and it came out perfect but, it was minimal and I had to stand on my head backwards to get the dangle of the angle....whew!! Good Work!!! Nice Indeed!! Guess I shouldn't have shown my wife the pics...now she's getting ideasand I'm too old for that $@%t
Yeah, I installed over 300' of it, and I made all the bead molding myself, so i actually went around every room twice... Thanks for the compliment.

I even did the electrical. lol... I think the bar was my favorite project yet. because it was all for me.

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Old 08-26-2012, 07:19 PM   #34
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Maybe I'm confused about a 5HP motor.


Thermal OL protect the motor, while breakers and fuses protect the wiring to the motor.
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Old 08-26-2012, 07:55 PM   #35
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Maybe I'm confused about a 5HP motor.


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Thermal OL protect the motor, while breakers and fuses protect the wiring to the motor.
I disagree, the thermal overloads protect the motor and branch circuit wiring, where as the breaker only supplies ground-fault and short circuit protection.

hence a 30 amp breaker on #12 AWG for example.
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Old 08-26-2012, 10:11 PM   #36
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Maybe I'm confused about a 5HP motor.


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Originally Posted by stickboy1375 View Post
I disagree, the thermal overloads protect the motor and branch circuit wiring, where as the breaker only supplies ground-fault and short circuit protection.

hence a 30 amp breaker on #12 AWG for example.
That one part that many home owner never really catch the answer why we do use the Art 430 for this purpose and from time to time someone will tell me nuts and they ran that to the inspector and in fact he did sided with me due I done it right.

But many of them did follow the nameplate but not understand the real protection by useing the OCPD sizing at all.

Merci,
Marc
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Old 08-27-2012, 11:27 AM   #37
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Maybe I'm confused about a 5HP motor.


Here's the thing about electric motors: Torque falls off as RPM increases. Unlike a gasoline motor, where torque increases along with RPM. The motor could very well be a 5HP motor installed in the tool/appliance *BUT* in the application it is being used in, it's only consuming 1-2 hp to get the job done. This is because the motor is probably virtually freewheeling driving the machine it's attached to (If it's a vacuum cleaner, that's the blower fan, a saw, the saw blade) If the motor were to be operated at it's full capacity, or at a near stalled condition, your breaker surely would trip!
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Old 08-27-2012, 11:40 AM   #38
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Maybe I'm confused about a 5HP motor.


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Originally Posted by av-geek View Post
Unlike a gasoline motor, where torque increases along with RPM.
I know this is OT, but this is not exactly true.
Torque increases and decreases with RPM.
At 5252rpm both TQ and HP are exactly the same.

Below 5252rpm any engine's torque number will always be higher than its horsepower number, and above 5252rpm any engine's horsepower number will always be higher than its torque number. At 5252rpm the horsepower and torque numbers will be exactly the same.

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