Motor nameplate says:
does this mean that the 240v rpm is 3450?
from what i've been seeing on this forum, the rpm doesn't change, but since I converted to 240, seems to not only spool up faster but runs faster??
btw ampmeter indicates 3 amps at idle vs. 6-7 on 120. (C;
The speed an induction motor runs at is determined by the frequency. If you'll look at the label there should also be a frequency listing (Frq: 50/60hz). The first listed RPM is for 50 Hz operation; the second is for 60 Hz.
120 vs. 240 volt theoretically should make the same horsepower and spin at the same speed. The difference is the quality of the line feeding the machine. With a 120v 1 1/2hp motor, you are generally at the limit of what a 15-amp circuit is sized for. When you convert over to 240v you are generally pulling nothing near what the line can handle, so the voltage drop is less resulting what feels like more power.
You are right about your observation on the amperage. At 240v the amp draw is half of the draw at 120v. Wattage (which is the measure of the total energy used) is the same. Wattage is Volts X amps.
alle is goot