Dwelling Garage Air Compressor Calc
- Thread starter WadeC
- Start date
- Location
- Illinois
- Occupation
- retired electrician
It is unlikely that you really have a 7hp motor. Look at the motor nameplate for the actually current. The 7 hp is very likely some type of "marketing" horsepower, such as "peak horsepower" and not a real number.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Does it have a cord and plug? What configuration?
I thought it seemed high. The owner told me it was 7hp. I told him I wanted to see the nameplate but the compressor is in another state. Did I use the correct calc?
Owner said he put a cord on it and plugs it into his welder receptacle
you were right. Nameplate says HP: Spl and Amp: 15
- Location
- Bremerton, Washington
Yep. That 7 hp may be under locked rotor. Similar to 2hp garage door openers
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Yeah those numbers are normally fudged. Does it also say 240 volts? According to T430.248 a 1 HP motor at 120 volts is about 16 amps. A 3 HP at 230 volts is 17 amps.
Yes 240v
kwired
Electron manager
- Location
- NE Nebraska
This motor likely will run on a 20 amp breaker with little or no trouble. And should even be able to use 14 AWG conductor as long as is not one required to use 60C ampacity table, which would include NM cables.