3 phase plug & socket
- Thread starter DCarr
- Start date
i would not recommend that. just get the proper connectors.
nehog
Well-known member
Not if his equipment is wired as wye instead of delta. And 120/208 is wye wired. Added to this is the big bang concept that at some point someone will try to use that setup as single phase.
The only safe and correct answer is to use a proper three phase connector which will have five pins: ground, neutral and three phases. There are twist lock plugs that will work just fine, that's what I have on my three phase generator set.
That statement is irresponsible,
there is a reason that there are non-interchangeable configurations for different voltages/ampere ratings/phases & being too cheap/stingy is not a valid reason to "re purpose" a receptacle.Just exactly where does the "neutral" come into the picture??
For me I use it to power the lights on the machine... or the DRO. Line to neutral is 120v.
lg
no neat sig line
nehog
Well-known member
Just exactly where does the "neutral" come into the picture??
120/208 wye has three phases, and a neutral. Whether he uses it or not is not the issue, it exists and needs to be on the plug.
There are two ways to do things, the right and proper way and kludged with the eventual probability that the kludge will come an bite one some day.
The original poster never said anything about having a 120 volt requirement. he simply stated "3-phase".
With this limited definition the neutral doesn't enter into the picture.You're reading more into it than what's posted
If you want to do things the "right / proper" way you need to have a complete definition of the operating parameters. Incomplete questions get partial answers.
Elroy stands behind his response because regardless if it's a delta or wye service , the neutral doesn't matter as he was NOT inquiring about a single phase leg.
In a pure 3-phase application, the neutral doesn't matter. All you need are the three legs and a ground. To get a fully true and accurate response the original poster needs to clarify his question. Elroy stands behind his response. At this point,the neutral is a moot point .
Being that this RPC is most likely at a residence 208V is not going to be there, the RPC will have a 240V output. There are other reasons why it's not 208V too,but no need to go into it since it's irrelevant IMO.
you dont have to use a connector with a neutral unless your load requires one. L15 connectors are installed in 120Y208 systems all the time for 3P4W loads
Thanks for all of the answers.
I could've used a 110v line at the machine also but didnt think about it.
My issue was solved when the seller of the Mill gave me a 5 HP 3 phase motor that I will make a phase convertor out of. I have a 3 HP ph. convertor that works great for my 2 HP Lathe, but it struggles with the 3 HP motor on the Mill.
I intend on stepping up and buying a VFD ( or 2 ) to use instead of running 2 motors to power 1 machine.
I could've used a 110v line at the machine also but didnt think about it.
My issue was solved when the seller of the Mill gave me a 5 HP 3 phase motor that I will make a phase convertor out of. I have a 3 HP ph. convertor that works great for my 2 HP Lathe, but it struggles with the 3 HP motor on the Mill.
I intend on stepping up and buying a VFD ( or 2 ) to use instead of running 2 motors to power 1 machine.
robertlynk
Well-known member
NOTE Phase converters are all delta wound so how do you get wye power as you assume.
also the idea of re purposing stuff that has the potential to cause great bodily harm is plain *** stupid
also the idea of re purposing stuff that has the potential to cause great bodily harm is plain *** stupid
-JP
Well-known member
To clarify, your response makes reference to "3P4W Loads" which by definition indicates a system configuration of 3Phase, 4Wire therefore requiring a neutral.
When referencing a receptacle, the correct and complete identifier is "3P4W Grounding" which indicates 3Pole 4Wire of which one of the connections is reserved for a ground conductor and hence does not include a neutral.
Key differance is Pole versus Phase and load requirements (system configuration) versus receptacle NEMA configuration.
JP
there has always been confusion using this reference between 3 phase systems and connector configuations. In connectors, 3P4W is 3 poles and a ground. Can be either 3 hots, or 2 hots and a neutral. Something non grounded would have equal numbers, for example I have a nema 18-60 plug (common in older hotel ballrooms) which is non grounding. This is referred to as 4P4W -has 3 hots and a neutral, no ground. Back to 3P4W, whether its 3 phase or not is determined from the voltage rating ex: 125/250 or 3 phase 250.
-JP
Well-known member
Yes, it can be confusing and that was the purpose of my post as you were referring to "Loads" instead of the receptacle (or connector as you note).
Your example of the NEMA 18-60 receptacle is correct as a 4P4W but only if you add the clarification of "NON GROUNDING" at the end so as to reference the receptacle configuration and not the system configuration. The reference to receptacles for #Poles #Wires should always follow with GROUNDING or NON GROUNDING.
Voltage rating has nothing to do with the system configuration notations. You can have 1P3W (single phase 3 wire) or 3P3W (three phase three wire) or 3P4W (three phase 4 wire) all of which can be a multitude of voltages. For example I can have a 3P4W system configuration that would be valid for 120/208V or 277/480V or 7200/12470V.
JP
again, youre talking about systems and im speaking to connectors. When you look at a 3P4W connector, it could either be single phase, or three phase with no neutral. If it has a / voltage rating then its single phase, if it has a 3o [VOLTAGE] on it then its obviously three phase.
the grounding vs non grounding is redundant. If the number infront of W is one higher than the number infront of P then its grounding. If the numbers are the same, its non grounding.
3P4W = grounding
3P3W = non grounding
4P4W = non grounding
4P5W = grounding
i think this all goes back to how the grounding conductor is not counted in permanant building wiring, but is counted in portable cords. ie: 12/4 MC and 12/5 SOOW both have 5 wires.
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-JP
Well-known member
I am actually making reference to both in an attempt to clarify the difference.
Your original post used the terms "for 3P4W loads" and when using this language it is defined as a system configuration that would require 3 Phase with a Neutral.
You may have things figured out in your head but when someone other than you attempts to research a product it can become confusing when interchanging the two identifiers.
JP
Your original post used the terms "for 3P4W loads" and when using this language it is defined as a system configuration that would require 3 Phase with a Neutral.
You may have things figured out in your head but when someone other than you attempts to research a product it can become confusing when interchanging the two identifiers.
JP
I am not an Electricist and wont claim to know a lot about it. And up until a couple of days ago while reading on this forum I had never heard the term ( or word ) " wye ", intitional I thought it was a misspelled word. I know of at least 5 people who are using 3 phase motors as phase convertors. With HP ratings from 3 HP to 25 HP and none of them have ever had one fail, cause them a problem or Bodily Injury of any sort. One of the guys using a 25 HP motor has been using it for 20 + yrs. to power a Huge ( 40" x 120" ) Lathe and a Bridgeport Mill.
With the Bigger motors ( 7 hp - 25 hp ) they use a 110v motor to get the larger one spinning and then flip on the breaker and it takes off running.
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To be specific, in laymens terms ... what is the problem with using a 3 phase motor as a Phase Convertor and what can cause the negative consequences ? Is the difference just in the way that they are wound ?
TIA
Back to your original question. Why wouldn't you just hard wire both machines to the converter? What are the machines? Usually, once one machine is running the other machine can be started. The first machine acts as a rotary converter for the second.
The phase convertor I have now is a 3 hp unit. The Mill I want to power has a 3 hp motor and the convertor struggles to get it going. The other machine is a 2 hp powered Lathe.
I dont think I would have the need to have both machines going at the same time.
I can buy a 5 HP convertor for approx. 350$ ... I might just go that route and try and sell the 5 HP 3 phase Baldor motor I have now.
My original question was posted before I had picked up the Mill and the extra motor. I also " assumed " that the Mill came with a 2 HP motor.
knobby
Well-known member
Check craigs list you would be amazed I picked up a disconnect with 2 600v pin in sleeve plug sets for $60