Bought me a 10L!

All you do is wire a few run capacitors to the hot from the wall and then to the 3rd leg of the motor and it will fire right up..... I have 2 VFDs and I don't notice a difference in power loss between the two. The VFD take forever to start up and the homemade static phase converter starts instantly. I don't know why people say static phase converters output less power because they are exactly how a single phase motor is wired without the centrifugal switch......
 
. I don't know why people say static phase converters output less power because they are exactly how a single phase motor is wired without the centrifugal switch......

Not sure about that statement. 3 phase motor has three windings in it. Wired up to single phase, two of the windings are energized, The third one is not connected, hence less power..
 
Once the 3-phase motor is running, it begins to generate voltage on the third (ghost) leg. Not full voltage however. That's how an RPC works.

"The rotating flux in the motor produces a voltage on the third terminal. A voltage is induced in the third terminal that is shifted by 120° from the voltage between the first two terminals. In a three-winding motor, two of the windings are acting as a motor, and the third winding is acting as a generator. "
https://en.wikipedia.org/wiki/Rotary_phase_converter

Because of this reduced voltage, it's important to be sure that any control circuits are connected to one of the two hot legs, not the ghost leg.

A static phase converter can be used as the starter for an RPC, so it's not a waste to buy one to use until you find a motor. The motor on my mill is serving as an RPC when I'm using my lathe. When (if) I find a cheap 5 hp 3-phase motor, I will use the SPC for the starter.
 
I don't know why people say static phase converters output less power because they are exactly how a single phase motor is wired without the centrifugal switch......

Like ASM said, with a static converter, you only have power on 2/3 of your windings. In an ideal world, that will net you 66% of the power output compared to energizing all three windings. The world isn't ideal though, so realistic numbers are somewhat lower. All the static converter does is provide a temporary "surge" of power on the third winding to start the motor spinning, then the converter may as well not exist. You can accomplish the same function by wrapping rope around your spindle and manually pull starting it while plugged in to single phase.

Being as I've not used the machine, I'd probably be in the same spot you are and not notice this loss, but that doesn't mean science is on vacation - the motor is creating less power, like it or not.

A static phase converter can be used as the starter for an RPC, so it's not a waste to buy one to use until you find a motor. The motor on my mill is serving as an RPC when I'm using my lathe. When (if) I find a cheap 5 hp 3-phase motor, I will use the SPC for the starter.

Now that's clever! I only have the lathe wanting 3 phase right now, but you make a very valid point about using the static converter as a temporary solution that doesn't go to waste in the long run.

One thing I'm not entirely clear on; I understand phase converters at a basic level, same goes for VFDs. I've read varying statements that either/both/neither can or will harm some motors. Some folks say it only applies to older motors, some say it's an urban legend, some seem to suggest simply having a VFD in the same room as a machine is enough to strip your lead screw and turn your ways to butter. Has anyone ever actually laid this debate to rest, scientifically? All I've manged to find in my searching are the full range of "I've been doing it for sixty years and never had a problem, so everyone else is wrong!" to "we sell the competing product, so the other guy's stuff will destroy your equipment," to "I once heard of a guy who'd heard a story..."
 
You can accomplish the same function by wrapping rope around your spindle and manually pull starting it while plugged in to single phase.

I've actually seen it done that way. Well, not the spindle, the motor shaft on the RPC.
 
Like ASM said, with a static converter, you only have power on 2/3 of your windings. In an ideal world, that will net you 66% of the power output compared to energizing all three windings. The world isn't ideal though, so realistic numbers are somewhat lower. All the static converter does is provide a temporary "surge" of power on the third winding to start the motor spinning, then the converter may as well not exist. You can accomplish the same function by wrapping rope around your spindle and manually pull starting it while plugged in to single phase.
I still do not get how the RPC, or static work, when the household current is 180 degrees apart, 3 phase has them 120 degrees apart. I don't get how you can run a 3 phase motor with the legs 180 degrees, instead of the 120 it would be looking for. Then the whole deal with the missing 3rd leg on a static convertor adds to my confusion. Maybe someone here can straighten out my thinking.

Electric-Household-2Phase.jpg
3phase.jpg
One thing I'm not entirely clear on; I understand phase converters at a basic level, same goes for VFDs. I've read varying statements that either/both/neither can or will harm some motors. Some folks say it only applies to older motors, some say it's an urban legend, some seem to suggest simply having a VFD in the same room as a machine is enough to strip your lead screw and turn your ways to butter. Has anyone ever actually laid this debate to rest, scientifically? All I've manged to find in my searching are the full range of "I've been doing it for sixty years and never had a problem, so everyone else is wrong!" to "we sell the competing product, so the other guy's stuff will destroy your equipment," to "I once heard of a guy who'd heard a story..."
A simple way I heard of thinking about an inverter, is that it changes the AC voltage, to DC voltage, then has a 3 phase inverter to electronically create all 3 phases. So they create true 3 phase. I don't see how the rotary, or static can make the 2nd and 3rd phase at the right times.

I have 5 invertors running in my shop (2 for the two motors on the Vasn Norman mill, and 3 powering 3 of the 4 heads of my Fosdock drill press). The next few months I will get 2 more, to power the 4th head, and the new to me South Bend. The 5 I have been running for over 4 years now. The wiring for them, is super simple. Programing has tad more thinking involved. I can assure you all my machines are still in the same condition as when they left the factories back in the 50's.
 
Superburban, the way my mind has always interpreted that (which may very well be wrong, because I have no formal education in this stuff, just interpreting things "my way.") is kind of tough to express without being able to draw (I'm a visual type learner..), so bear with me.

60hz 3 phase, with 120* offset legs essentially gives you 180hz power, with the "peaks" occurring every 1/180th of a second, or 0.0056 second intervals. Running on "standard" power with 180* offsets gives you 120hz power at 1/120th of a second, or 0.0083 second intervals. The motor doesn't care or know that the legs are offset by the "wrong" number of degrees, they just get charged at different time intervals, given the same 60hz source power. I've always assumed this just results in a 33% reduction in RPM, all else being equal. So a 1725rpm 3ph motor will run at ~1150rpm on single phase. I think. Again, there's no formal education behind this, so I could be 100% incorrect. Just how my brain has reconciled it.

Assuming my above example to be accurate, using a rotary converter will then generate power on 120* legs, albeit at a slightly different base frequency. I'm not sure if this is true or not, as I've only ever used phase converters in *very* limited circumstances, and never a situation where I could "dig in" to see what's going on under the hood.

Static phase converters aren't really "phase converters" in any sense of the word. They do nothing to change the phase output of your power, they simply allow you to start a 3ph motor and keep it running on single phase. To my understanding, there is no "three phase" output from them at all, except an initial "jump start" to energize the third winding to get the motor running. I think "phase converter" is a bit of a misnomer for statics, but again - I'm no expert.
 
Good point on the timing, I was not thinking that way. My brain is mechanical, I have a harder time wrapping it around flux, slip, induction, capacitance, ect. I can rebuild motors, but could never design one.
 
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