115/230 Volt Motor Wiring

CluelessNewB said:
8.6 amps @115 V would be about 1/3hp
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8.6 amps @ 115 V = 989 watts, admittedly ignoring power factor.
746 watts = 1 HP (assuming 100% efficiency).
I'm not sure how you came up with 1/3 HP. At that rate you couldn't run a 1 HP motor on a 20A 120V circuit.
 
Actually that was a typo I should have said 1/2hp not 1/3hp. I may be a little bit pessimistic. Below is a list of actual 110-120V motors that I can easily access in my shop to read the plates. All but the Grizzly are older motors probably 1950s-1960s which is what I suspect the vintage of the motor above is.

MakerModel HorsepowerCurrent
Walker-TurnerKAB 3E1/36.0A
Craftsman? can't read3/49.3A
Walker-TurnerKAB 5E1/27.6A
Dayton5K45581/27.8A
Dayton4K781V1/210.0A
Delta6300D1/36.6A
Delta21431/36.0A
Grizzly? Taiwan mid 1990s vintage224.0A
 
No where near 100% due to losses- the Dayton 4K781V is surprisingly inefficient, it takes more current than the 3/4 hp Craftsman
Another reason not to buy Dayton motors :)
 
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That little flat plate you pulled off to expose the terminals, look on the back side of it and see if there is a wiring diagram for high/low voltage.
With dual voltage motors you are either wiring two sets of windings in series OR parallel. Series for 240v and parallel for 120v.
Generally, not always but generally you swap leads 5 and 8 to change rotation .
 
markba633csi said:
No where near 100% due to losses- the Dayton 4K781V is surprisingly inefficient, it takes more current than the 3/4 hp Craftsman
Another reason not to buy Dayton motors :)
Click to expand...

That Dayton is an outlier but even modern Leeson & Baldor 1/2hp motors are typically in the 7 to 8 amp range.
 
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