Question for Electricians - 110v vs 220v. etc

[Tidybuoy]

I have been looking at a variety of electrical items including a hot tub - spa, table saw, air compressor, and koi pond pumps.

I noticed that some are 110 or 120v and others are 220 or I think 230v. I'm just wondering if there is a reason why you would want the higher 220v for some of these items.

I realize there is some cost factor to having 220 installed but if it is better in the long run, and I expect these things to be around for a long time, then to me, it would be worth it.

I also saw a table saw on Craig'slist that said is was switchable from 110 to 220 with just a switch.

Any explanations would be great - this is a big puzzle to me.....................Vern

[nota]

many mid sized motors will be dual wound for both voltages
so they donot need as many different ones in stock
220v uses two 110 lines so 1/2 the amp flow for the same work
110 vs 115 vs 120v is just naming when some regions use different standards
all a/c power is the same now

but 220 is slightly more efficient than 110
esp for the high power uses like hot tub or a bigger air compressor
or a bigger table saw but requires the bigger outlets and wiring
for small fish pond pump not so much advantage or need for 220

[Joeaksa]

If its a heavy load draw, I always use 220v.

Even for a cell phone charger, when I am overseas and using 220v, it charges faster.

[imcarthur]

In a house, a 240 Volt appliance/motor splits the load over the 2 incoming 120V lines which halves the amperage per line allowing for smaller wiring conductors - reducing cost without reducing safety. Essentially the same reason that the electrical company steps the voltage up for long distance cable runs. It also balances the current over the 2 legs of your electrical panel. You never want one 'side' to have significantly more than the other.

Now, overseas use of shavers etc is different because you also have a frequency difference - usually 50 Hz versus our 60 Hz - as well as a voltage difference. Motors & chargers work slightly faster due to the frequency. A 60 Hz unit will work slightly faster with a 50 Hz frequency.

Ian

[T77911S]

the biggest advantage is you dont need bigger wires to run a high HP motor. the cost is still the same. for a bigger motor, the starting will be easier. there is also less voltage drop for longer runs.

$$=power = amps x volts

2 motors i looked up.

120v x 15.2 amps = 1824 watts
240 x 7.6 amps = 1824 watts

120x 33.8 = 4056 watts
240x 16.9 = 4056 watts

most people know that the amps are cut in half, but it is still volts x current.

110, 115. and 120 are all the same. votls at my house runs 116 to 121.
220, 230 and 240 are all the same
these voltages come from a delta transformer, i think.

120/208 comes from a wye trans former. the 120 is the same but not the 208.
240 equipment will not work as well connected to 208.

anything you run for a long time, like a lawn well is better off on 240. if you dont move your table saw, 240 is better because of the load balance, and again, less current per wire. the load on wires causes them to heat up. the current rating of a wire is based on its ability to dissapate that heat. it is possible to put enough load on a circuit, not trip the breaker and heat the wires to a point of causing a fire.

i put my lawn well on 240 because the house was wired so the outlet for the well ran through the GFI in my bathroom. i noticed the outlet was getting very hot if i ran the well for a long time

[stomachmonkey]

I use 220, 221. Whatever it takes.

[rick-l]

Voltage is analogous to pressure in a garden hose. If you need so many gallons per minute at the end of the hose you can do it with a smaller hose if you have twice the pressure.

[fingpilot]

Funny, I always thought of it as a 'gearcase'. Higher volts= lower gear for loads.

[nynor]

Originally Posted by stomachmonkey

I use 220, 221. Whatever it takes.

hah! beat me to it!

[rick-l]

Force in the motor is produced from F=q(v x B) where
F is the force, B is the magnetic field, q is the electric charge of the electron, v is the instantaneous velocity of the electron.

So for the most force you want as many q's (electrons) as you can get to go by and as fast as you can get them to go by, or big I (amps) former and big V (volts) later.

[Tidybuoy]

My roomate in college was mastering in electrical engineering. He was always complaining about how hard it was. I always thought he was a whiner..........