My girlfriend’s parents own a sewing company that they’re selling, and asked her to list some of the sewing machines on craigslist. She’s received some interest, but many of the respondents are asking if the machines use 3-phase power. Now, we can’t get over to check the machines for ourselves until at least Saturday, and her parents barely speak (much less read) English, so asking them to check the information panels is pointless (they seem to have no idea what 3-phase power even means, in any case). We looked the models up online, but were unable to find this particular information. Is there some tell-tale sign to let you know whether something’s single-phase or 3-phase? Something about the plug, anything? Any help would be appreciated.
The plugs would certainly be different than the typical US 3 prong household plugs.
5 prongs on the plug is a pretty good bet. Most 3-phase would have 4. 3 phase could have only 3.
The only sure way is to read the plate on the machine.
You could also check to see if the building its in has 3-phase. Then you could at least eliminate the possablity
Yet when trying to sell a piece electrically powered machinery, precise information about the power it requires is pretty much essential - no sensible buyer would offer a good price while he’s in doubt about whether the machine will be of use to him.
So I suggest you say that you’ll soon be making detailed info available, and will not be selling the equipment until that time.
(You might possibly speed things up by asking the parents to e-mail you photos of the data plates.)
Good chance the machines are hardwired to a disconnect.
Best way for someone with zero knowledge to determine the motor type is to look at the motor nameplate. The plate will list several numbers:
Voltage, which is followed by a V (for volts) - e.g., 120V, 208V, 230V, etc…
Amperage, which is followed by an A (for amps) - e.g., 15A, 30A, etc…
Frequency, which is followed by Hz (for Hertz) - this will usually be 60 HZ in North America, but 50 HZ is used in other places.
AND finally
The number of phases will be listed as 1Φ for single phase, 3Φ for three phase. That
is the greek letter Phi, and it’s usually fairly obvious on the nameplate.
Another number you might find is horsepower (Hp), and this might help determine the phase type as single phase is usually used for smaller motors, but just look for 1Φ or 3Φ.
Yeah, that’s basically what we did. When we got the questions, my girlfriend called and asked her parents what kind of power the machines used, which we thought would be a reasonable enough method for getting additional information to potential buyers, but apparently they don’t possess even the most basic knowledge of how their equipment - which they’ve used in different configurations for the past 30 years - works. they didn’t even know the names of various sewing needles, which you’d think would be pretty rudimentary. Maybe part of it’s a language issue, but I think it’s more the fact that they’re scared of technology (which means they can’t e-mail us pictures, since they don’t own computers and have never used the internet). It’s really become quite a hassle trying to help them out with this seemingly simple transaction.
Thanks to all for your responses. Hopefully my gf can explain enough so they can give us a reliable answer.
OK, get them on the phone and ask them to go out to one of the machines, and describe to you how the cord plugging into the wall outlet looks.
IF it doesn’t plug in, but is hard wired into the wall, it’s likely 3-phase (or 1-phase 240V). You can’t tell without looking at the nameplate on the device.
If they describe the standard USA 2 flat vertical blades (with or without a round grounding pin), it is standard 1-phase 120V.
If it has a round grounding pin, and 2 flat horizontal blades, it is 3-phase 208V.
If the plug has
- a round grounding pin, 2 vertical flat blades, and a 3rd blade (either vertical or L-shaped) opposite the ground pin,
- or if the plug has 3 flat blades, slanted at an angle to each other,
- or if the plug has 3 curved blades that twist-lock into the plug,
then it’s either 3-phase 208V or 1-phase 240V – you can’t tell without looking at the nameplate on the device.
See NEMA connector - Wikipedia for more details & pictures of these.
But the way to know for sure is to read the nameplates on the machines. Besides, you really need to specify brand name, model number, motor horsepower, and voltage (and some info about lifetime hours used) for an effective ad. Buyers will want to know all that stuff.