3Phase From 2 Services?

[OverkillYJ]

I have two services on my property. One is 100Amp, and one is 200Amp. I recently purchased this compressor and will be selling it. That would be easier if I could just wire one junction box to run three phase equipment as needed.

I was hoping someone would tell me I can take two hot wires off of one service and use something that doesnt cost a fortune to double the voltage for the higher voltage leg of a 3 phase service. I know there are ways to do it with a device on a single service, but I was hoping since I have two at my disposal I could save some money and find an easier way. I assume I would just get higher amps if I put the wires together, not higher voltage? I asked a couple people I knew but no one could give me an answer, so here I am. It is kind of confusing since they say a motor is running 230 volts off of one service. So if I rip open a bad motor would there be something in there that combines them to create 230volts for the motor, or are they saying the motor gets two lines powering it and adding them together even though it is not really a 230 volt input?

I have done a lot of household wiring. I know what the Delta wiring configuration is, but have never worked on one. I also have never seen what is different at the pole for 3 phase if anything. Any help you guys could offer who work with this stuff would be a big help and answer a lot more questions for me about 3 phase I dont even want to post. I also tried Google for an answer to this but didnt find anything.

 

[zmaxmotorsports]

Nope its not that simple

 

[OverkillYJ]

So I am guessing it it only in industrial parks and things you can get it? Larger areas of commercially zones properties I assume?

 

[teamextreme]

So I am guessing it it only in industrial parks and things you can get it? Larger areas of commercially zones properties I assume?

Correct. They do make phase converters that would work for you that will convert single phase to 3 phase. Google phase converter, there have been plenty of threads on here about them and lots of info on the net about them.

 

[wyliesdiesels]

You cannot combine the hots of different single phase service to get 3 phase. It doesnt work that way. Single phase has 2 hots that are 180* out of phase with each other. 3-phase has 3 phases that are 120* out of phase of each other..

If your motor needs 3-phase 240v u either need 3-phase service or u need a phase converter such as a rotary phase converter or a VFD(variable frequency drive) with single phase service...

In regards to how it works. 3 phase transformers have 3 primary windings and 3 secondary windings or 2 secondary windings if the load is small and the PoCo uses an open delta to save on transformer costs...

Single phase transformer has one primary winding and one secondary winding!

 

[BLACK DEATH]

I've passed up nice compressors that had three phase power as they seem to sell cheap as no one wants a used compressor or can use three phase power for home use.
Those phase converters are not cheap one bit when I did a google search

 

[OverkillYJ]

I hate the timeout time on this site. Anyone know how to adjust it? I cannot find it. It keeps locking me out and screwing up my replies. so I have to type it over.

Anyway...I found 10HP single phase motors. I knew they were available before buying this. This morning after taking measurments I determined this is a 220 Gallon tank.

@Black Death. I paid less than what the tank is worth for the entire thing. If the pump and motor were stolen off the top I would still turn a nice profit.

@WYLIESDIESELS. That type of answer is why I use this site. Thank you for taking the time to give me a solid answer. Googling this was giving me a headache. That helped a lot. Just so I know, since I live in the city within 100ft of 4 decent size businesses I know I can get a commercial zone here. I would bet the lines are on my pole and I live near power stations, and radio antennas. The previous owner has a commercial licence with the city as recently as 2004. Could I just call the power company and say I want a 3phase service instead of the two single phase services I have? Could you give me like a rough idea of what they would tell me? Also, would my bills be drastically different if my energy consumption was the same?

As for the setup, I bought this with my father in law. He needs a tank, and I need a pump. I only have a 2HP motor, and my pump just started knocking. I was looking for a 5HP and came across this for about 1/3 the cost of a smaller 5HP. Because it is so big, and we got it so cheap we are going to clean it up, replace a couple of gaskets, and sell it. We know we can get our money back and clear enough for a tank and compressor more in our size range. We just cut the wires yesterday morning, and this thing ran perfectly.

I have thought about keeping it. Argument I am getting into here is on electricity consumption if I did go get myself a 10HP single phase motor. I am arguing it would be a negligable difference if I used the same amount of air. This does cost more to run, but it would fill my tank so quickly, and be so oversized I wouldnt have to worry about killing it. My father in law is arguing any 10HP motor costs so much more to run my electric bill would go through the roof. I would bet we are both a little bit right and wrong. Can anyone give me a solid answer on the energy consumption differences? If you could also tell me what you know that backs up what you say that would help me a lot. Because then I can go to him with an explanation instead of just saying people told me something.

Thanks again for all the help.

 

[ridefst]

Could I just call the power company and say I want a 3phase service instead of the two single phase services I have? Could you give me like a rough idea of what they would tell me? Also, would my bills be drastically different if my energy consumption was the same?

You would have to maintain one of the single phase services to run all the 120/240 items that you currently have - or else buy a transformer to step the 277/480 3-phase down to 120/240.
The transformer would be expensive, so you'd likely end up with two services still, one single and one three phase - which I expect would cost more overall.

3 phase motors are generally a little more efficient, but overall your costs would be similar for the same energy consumption.

Looks like about $700 for a 10HP 230V VFD that should be able to take single phase in, and put out three phase (though the mfg will never suggest that, it almost always works)

 

[Falcon67]

I can't say for sure, but around here if you got a quote from the PoCo for installing 3 phase on a building you'd be shopping for a single phase motor or looking for a used 15~20 HP 3 phase motor to build you own rotary phase converter. The PoCos don't do that stuff for free like they drop a single phase line to a residence. You'd also be paying a commercial rate on power.

 

[404]

By running a smaller pulley size on the motor this pump will run at a lower RPM and require less HP motor to drive it. The limit to this is that pumps have a minimum recommended RPM (I assume so it gets enough lubrication but I am not sure.)

So with the correct motor pulley your existing 5 HP motor might run this pump. Reducing the pressure switch high limit pressure will also reduce HP needs.

Regards,
404

Edit : sorry just realized that you have a 2HP motor. My bad.

 

[404]

The electricity for 5 HP for 2 minutes and 10 HP for 1 minute is the same. And think of the media blaster this could run.

 

[justsam]

Unless you need the capacity of this, I think I would resell, and use the profit you suggested to scale back a bit.

While it may be that a Briggs Stratton is less efficient than a small block Chevy, there is still an issue of scale. And if you do not need the HP from a small block Chevy than it does not make sense. It is true that work is work in terms desired output, but there are also parasitic losses when you scale up that must be overcome.

Also the cost of a 3 phase convertor is one consideration, and if you elect to go 10HP single phase, you will have the cost of the new motor, as well as the cost of providing wiring to a 10HP motor. Get ready for some serious copper!

 

[ishiboo]

Just so I know, since I live in the city within 100ft of 4 decent size businesses I know I can get a commercial zone here. I would bet the lines are on my pole and I live near power stations, and radio antennas. The previous owner has a commercial licence with the city as recently as 2004. Could I just call the power company and say I want a 3phase service instead of the two single phase services I have? Could you give me like a rough idea of what they would tell me? Also, would my bills be drastically different if my energy consumption was the same?

Sure. If there is 3-phase. It's pretty simple to see... take a picture of a main power pole in front of your building and we'll tell you. (It's the # of wires being usually 2 for single-phase or 3 for 3-phase, but it's easier to look than to explain what wires are for other services and don't count.)

The bills would not be drastically different, but the install would be way more than the cost of a phase converter or new motor for not just that compressor but any additional 3-phase units you would consider.

I have thought about keeping it. Argument I am getting into here is on electricity consumption if I did go get myself a 10HP single phase motor. I am arguing it would be a negligable difference if I used the same amount of air. This does cost more to run, but it would fill my tank so quickly, and be so oversized I wouldnt have to worry about killing it. My father in law is arguing any 10HP motor costs so much more to run my electric bill would go through the roof. I would bet we are both a little bit right and wrong. Can anyone give me a solid answer on the energy consumption differences? If you could also tell me what you know that backs up what you say that would help me a lot. Because then I can go to him with an explanation instead of just saying people told me something.

Thanks again for all the help.

As 404 said, given the same air consumption, the costs of running a 2hp would be essentially the same as running a 10hp with pumps sized appropriately for each motor. Given the same air usage, the 10hp would cost a lot more to run per minute but run a lot less minutes than a smaller motor.

 

[KenC]

You would have to maintain one of the single phase services to run all the 120/240 items that you currently have - or else buy a transformer to step the 277/480 3-phase down to 120/240.
The transformer would be expensive, so you'd likely end up with two services still, one single and one three phase - which I expect would cost more overall.

3 phase motors are generally a little more efficient, but overall your costs would be similar for the same energy consumption.

Looks like about $700 for a 10HP 230V VFD that should be able to take single phase in, and put out three phase (though the mfg will never suggest that, it almost always works)

Call 'em and ask. I did and now have a 120/240 3ph, hi leg service. No cost!
Of course I had to install a panel/breakers/and wire to the weatherhead but no install cost for the service drop and transformer.

wire your motor for 240 and done! just be aware that one lug of the panel cannot be used for other than 3 phase as it will be the high leg. but you will have 120 and 240 single phase as well as 240/3ph.

 

[FreddiFiche]

You cannot combine the hots of different single phase service to get 3 phase. It doesnt work that way. Single phase has 2 hots that are 180* out of phase with each other.

Not really. Single phase is single phase. If they were 180* out of phase with each other, they would cancel. 220 (240) is the voltage from end of winding, to end of winding, on the transformer. The Neutral is just a center tap in that winding, creating 110 (120) to either winding end.

 

[ishiboo]

Not really. Single phase is single phase. If they were 180* out of phase with each other, they would cancel. 220 (240) is the voltage from end of winding, to end of winding, on the transformer. The Neutral is just a center tap in that winding, creating 110 (120) to either winding end.

War wot words. He is correct, they are the same waveform shifted 180 degrees.

Electricity does not cancel.

You have +120v on one, -120v on the other (170 peak)... 120v - -120v = 240v potential.

 

[wyliesdiesels]

I hate the timeout time on this site. Anyone know how to adjust it? I cannot find it. It keeps locking me out and screwing up my replies. so I have to type it over.

No kidding, im with you on that. Just the reason why i copy my comments before posting in case it times out...

@WYLIESDIESELS. That type of answer is why I use this site. Thank you for taking the time to give me a solid answer. Googling this was giving me a headache. That helped a lot. Just so I know, since I live in the city within 100ft of 4 decent size businesses I know I can get a commercial zone here. I would bet the lines are on my pole and I live near power stations, and radio antennas. The previous owner has a commercial licence with the city as recently as 2004. Could I just call the power company and say I want a 3phase service instead of the two single phase services I have? Could you give me like a rough idea of what they would tell me? Also, would my bills be drastically different if my energy consumption was the same?

The answrs to most of this is dependent on the PoCo. I know that some PoCos will give 3-phase service to residence shops so it really varies. Call 'em.

As far as your bill, u will most likely end up with a higher bill with 3-phase. This is because with 3-phase most PoCo's not only charge for the KWs used, but also a 'demand charge' which is measured as the most KW used in a given time period say 15mins AS WELL AS 'peak rates' and 'off peak rates'. #-phase panels cost more and the PoCo may charge for the installation as well. If u dont have primary 3-phase then thats most likely another cost. Dont forget permits on top of all this!

Can anyone give me a solid answer on the energy consumption differences? If you could also tell me what you know that backs up what you say that would help me a lot. Because then I can go to him with an explanation instead of just saying people told me something.

Thanks again for all the help.

a 240v single phase 10HP motor will use around 50a or 12,000 watts. A 5hp is gonna be just over half that. This is based on the NEC FLC charts. As far as consumption that depends on how long its running....

You would have to maintain one of the single phase services to run all the 120/240 items that you currently have - or else buy a transformer to step the 277/480 3-phase down to 120/240.
The transformer would be expensive, so you'd likely end up with two services still, one single and one three phase - which I expect would cost more overall.

3 phase motors are generally a little more efficient, but overall your costs would be similar for the same energy consumption.

No he wouldnt need to maintain a single phase service if he gets a 240v/120v center tapped delta 3 phase service. 480Y/277v is just one type of 3-phase

The electricity for 5 HP for 2 minutes and 10 HP for 1 minute is the same. And think of the media blaster this could run.

Depends. Every motor has different FLC for the same given HP....

Sure. If there is 3-phase. It's pretty simple to see... take a picture of a main power pole in front of your building and we'll tell you. (It's the # of wires being usually 2 for single-phase or 3 for 3-phase, but it's easier to look than to explain what wires are for other services and don't count.)

The bills would not be drastically different, but the install would be way more than the cost of a phase converter or new motor for not just that compressor but any additional 3-phase units you would consider.

Most 3-phase services are gonna cost a lot more because of what i said above....

Call 'em and ask. I did and now have a 120/240 3ph, hi leg service. No cost!
Of course I had to install a panel/breakers/and wire to the weatherhead but no install cost for the service drop and transformer.

wire your motor for 240 and done! just be aware that one lug of the panel cannot be used for other than 3 phase as it will be the high leg. but you will have 120 and 240 single phase as well as 240/3ph.

Yup, gotta watch out for the stinger- 208v between phase and neutral!!

Not really. Single phase is single phase. If they were 180* out of phase with each other, they would cancel. 220 (240) is the voltage from end of winding, to end of winding, on the transformer. The Neutral is just a center tap in that winding, creating 110 (120) to either winding end.

The board just had this discussion in another thread :/ .....Not gonna waste my time going into it again...try googling it.......

 

[FreddiFiche]

The board just had this discussion in another thread :/ .....Not gonna waste my time going into it again...try googling it.......

Yep, I did....

A transformer supplying a three-wire distribution system has a single-phase input (primary) winding. The output (secondary) winding is center-tapped and the center tap connected to a grounded neutral. As shown in Fig. 1. either end to center has half the voltage of end-to-end. Fig. 2 illustrates the phasor diagram of the output voltages for a split-phase transformer. Since the two phasors do not define a unique direction of rotation for a revolving magnetic field, a split single-phase is not a two-phase system



'out of phase' with each other is a matter of Measuring point. IF the reference was one end of the transformer, to neutral, I would see a Sine wave. If I measure from the same end of the transformer, to the other end, I would see a perfectly synced sine wave of double the amplitude. if you use a scope, referenced to neutral, and look both ends, they look out of phase, only because of the reference point. At the end of the day, this is single phase power, by everyone's standards. Two phase service would have to legs, 120* out from each other, which most (all?) home service isn't.

 

[FreddiFiche]

War wot words. He is correct, they are the same waveform shifted 180 degrees.

Electricity does not cancel.

You have +120v on one, -120v on the other (170 peak)... 120v - -120v = 240v potential.

Not trying to start a war. Really. Just trying to clarify, or learn. Look at my other posts on the forum....I'm not exactly a troublemaker.

See my above post. The waveform only shifts, depending on your reference point. Change the reference point to one end of the winding, perfectly in phase, only amplitude changes. It LOOKs like they are out of out of phase if you look 'up' the transformer, and 'down' the transformer, from the tap. I would never reference this as two phase, or out of phase.

All waves cancel...Electrical, sound, Radar, etc. Two wave forms of equal amplitude, 180* out, result in nil. But thats not what is going on here....single phase, in phase, depending on your reference point.

 

[wyliesdiesels]

Here, i found the thread: http://www.garagejournal.com/forum/showthread.php?t=269382

The explanations in that thread should hopefully clear up your confusion!

 

[FreddiFiche]

Here, i found the thread: http://www.garagejournal.com/forum/showthread.php?t=269382

The explanations in that thread should hopefully clear up your confusion!

I read it....and really not trying to be a pain here, or start a fight....But it doesn't change what i wrote.

They look out of phase because of the reference point. (only) In this case, the neutral tap. If you CHANGE the reference point to one of the legs, and put two scope channels on neutral and the other leg.....you'll see that both waveforms are perfectly in sync, just one is twice the magnitude. (The other leg)

The Neutral reference point make it LOOK like it's out of phase, but under no circumstance would you call this a 2 phase system.

Again, I'm not trying to be combative. Really. My job is working for the largest US manufacturer of devices that rectify three phase power, charging a DC bus, and then rebuilding it to three phase power of varying frequency. We sometimes use Single Phase 240 to charge the bus (of course derating the VFD). This would never be referenced as two phase....

 

[wyliesdiesels]

No one is saying that single phase is actually 2 phase! And actually the correct term is split phase. Regardless, the part about 180 out of phase with each other is correct...I was taught that and thats how they teach it in trade schools as well as the union...maybe were not explaining it in a way u understand it....its too late tonight and im way too tired to try and explain it a different way....maybe someone else wants to take a stab at it!

 

[FreddiFiche]

No one is saying that single phase is actually 2 phase! And actually the correct term is split phase. Regardless, the part about 180 out of phase with each other is correct...I was taught that and thats how they teach it in trade schools as well as the union...maybe were not explaining it in a way u understand it....its too late tonight and im way too tired to try and explain it a different way....maybe someone else wants to take a stab at it!

I don't think there is anything to take a stab at. Let's try this....Drop the neutral tap. Measure the Voltage with a scope. Do you see a single sine wave, or do you see two superimposed sine waves? You see one wave.

The two halves of a split phase are in sync with each other. They only LOOK to be 180* if measured from a neutral reference point, but they are IN Sync.

By definition, same winding, same expanding and collapsing of fields, same sync. Adding a tap doesn't change that.

I think i do understand what you are saying, and what the trade schools and union are teaching around you. What you are not grasping (my fault) that around here, we are cautious about saying that it is 180* out, which implies two phases. It only looks 180* out, in reference to the neutral tap.....

On second thought...Nevermind. I'll never speak of it again.