VF-2 Wiring Question...Where does manufactured leg from phase converter go?
I, as well as the electrician and electrical engineer were assuming that the manufactured leg from the phase converter needs to run to the the L3 position on the machine breaker. Can anyone confirm this?
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The main thing is is to ensure that the 1ph 240 pair feed the control and low voltage section, the 3rd leg would just supply the 3ph dependent items such as 3 ph motors etc.
Dependent on the machine, if the low voltage 1ph circuits is spread across the 3 phase, then they ideally should be swung over to the 240v 1 ph supply.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Thanks for the response. That's what I was figuring. Maybe a Haas electrical genius can chime in and let us know which legs of the main breaker power the single phase stuff.
--Andrew
I have wondered which legs supplied what. Possibly one way to find out is to use a clamp-on ammeter to measure the current in each leg when the machine is idle. I wonder if you could get one sensitive enough to show the difference when the only load was the internal low voltage power supplies.Originally Posted by super95awd
Certainly it should be possible to find which legs supply the coolant pump and chip auger because these have a significant current draw.
Of course I guess this approach doesn't help if you do not have the machine powered up and want to know the answer before connecting it.
An open mind is a virtue...so long as all the common sense has not leaked out.
Hopefully you have the service manuals and schematics, if so this will tell you right away.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Haas!!! Provide an electrical schematic!?!
I have no real credibility for this other than it is handed down information from those more knowlegeable than me, but I have always been told to wire the "wild" leg so to speak to L2.
So with that, I have probably only confused the issue more.
Too bad, this would be one of my conditions on whether I buy the machine.Haas!!! Provide an electrical schematic!?!
As a last resort it should not take an electrician or technician to do a little 'reverse engineering' of the panel wiring to discover the control circuit feed.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Actually, Haas does now provide some schematics on a CD included with the manual, but I don't think it is as detailed for what is being discussed here.
Must be very difficult to do any trouble shooting, or do Haas claim they will never go wrong?
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
On my Haas, legs #1 and #3 are the legs that are used to provide power to the other areas. Therefore the wild leg is on #2.
On any machine you wire, CNC, Manual mills lathes etc., always avoid using the wild leg for activation on mag starters etc.. It may work for a while, but in the end it will usually end up burning out the coil in the mag starter.
To find the leg, just use a meter and check each leg to ground. One will be much higher and that is the wild leg. If you check leg to leg, then wild leg to other will be higher and normal leg to normal leg will be lower. Easier to check to ground though.
In my shop, I have all of my three phase outlets wired to have the wild leg in the same place on each outlet, just in case someone changes one around or plugs in a different portable machine.
Mike
Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28
If you look inside your panel, you will see the main manual breaker. It will have the three main current wires going into it. You will also see three small red (on my machine) wires on the same incoming side. I believe these are for the small fuses that indicate if a leg has blown the fuse.
Below that manual breaker, is usually the main breaker that is engaged when you push the start button. On the outgoing side of that mag started will be the three main lines and two small lines, usually red and black. These are the power lines for the 120v circuits I believe. The one that does not have the small line, like I said #2 on mine, is where the wild or ghost leg goes. That leg will only be used for three phase items, which have no problem handling the extra voltage.
Mike
Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28
On items such as contactors and solenoids, I suspect the problems arise due to dips in the generated leg rather that high voltage, most 1ph AC magnetic devices can handle some over voltage with no problem, the stress comes with dips in the gen. leg when 3ph devices kick in.
This is one reason I spec in DC solenoids and use contactors with DC coils if possible.
The hysteresis curve on a DC magnetic device is much wider than that of AC devices such as these.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Not going to tell you that you are wrong, but I think it is over voltage. Measured voltage on my convertor is 120v on two legs and 195v on the wild leg. My surface grinder, on which I wired the wrong leg to the contacter, lasted a few times, but quit. Nothing wlse was running at the time.
See below from Smith Electric Motor:
Most rotary phase converters produce 3-wire Delta Power. The "wild leg" on a phase converter is usually defined by measuring the three voltages to ground (neutral) rather than line-to-line.
In Figure 9, the L1 and L2 points on the triangle represent the single-phase line and T3 is the Generated Leg. The ground symbol shows the single-phase neutral (N).
L1 to N is 120 volts.
L2 to N is 120 volts.
T3 to N is 208 volts.
195v or 208v, that can be hard on a 120v coil.
Mike
Added:
When you look at the path the T3 voltage takes to get to neutral, it is obvious that the "wild leg" is not really wild at all. It is simply electrically farther from T3 to the neutral point, and the distance through the winding simply increases the voltage reading by a factor of 1.73.
Remember that the system neutral is never connected to the rotary windings, and the 3-phase load does not recognize line-to-Neutral voltages.
The T3-to-Neutral voltage is useful for identifying T3 among a bundle of wires, but do not use it to determine whether voltages are balanced. Imbalance is only gauged by line-to-line voltage measurements.
Also, in my experience, when voltage drops on the coil line, the starter drops out and the voltage in the coil ends until the button is pushed again.
Mike
Last edited by Machineit; 11-14-2011 at 02:49 PM. Reason: Added additional
Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28
I have never had to tune a RPC that high, here is a trace showing the 3 phases from the design I based mine on from Fitch Williams who did alot of pioneering in RPC tuning and design.
This would seem to account for the high voltage measurement, I never measure to neutral.
Al.The T3-to-Neutral voltage is useful for identifying T3 among a bundle of wires, but do not use it to determine whether voltages are balanced. Imbalance is only gauged by line-to-line voltage measurements.
Last edited by Al_The_Man; 11-14-2011 at 04:02 PM.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Ya, HAAS certainly uses there own PCB's everywhere, and the prints are really bad, I think on purpose. That being said, they really aren't much more complicated than a home computer. Once you dig around a bit, not to hard to figure out.Must be very difficult to do any trouble shooting, or do Haas claim they will never go wrong?
Al.
I have always used phase converters with my Haas machines. I always install the generated leg to T3. But on this new machine this conversation got me to thinking.If you look inside your panel, you will see the main manual breaker. It will have the three main current wires going into it. You will also see three small red (on my machine) wires on the same incoming side. I believe these are for the small fuses that indicate if a leg has blown the fuse.
Below that manual breaker, is usually the main breaker that is engaged when you push the start button. On the outgoing side of that mag started will be the three main lines and two small lines, usually red and black. These are the power lines for the 120v circuits I believe. The one that does not have the small line, like I said #2 on mine, is where the wild or ghost leg goes. That leg will only be used for three phase items, which have no problem handling the extra voltage.
Mike
So for some reason I have the generated leg on the center connection on the breaker. But there is no markings as to L1-L2-L3..so I "think" the tech that did the install had me put it there..but I don't remember.
In the picture I have attached the small wire below are numbered 1-2-3 right to left....Thoughts?
Gary
Well just to follow up, neither my service manager nor my install tech said that it mattered which leg of the breaker the generated leg went to. I left mine on L3 and all seems fine.
Sure glad we went through this then.
Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28
I know I am. Mine was wrong..and it does matter.Sure glad we went through this then.
When I went to take the pictures for this thread I noticed that the machine breaker was not numbered..Now I know it matters and the install tech must have told me the center (L2)...but I honestly don't remember.
A lot going on that day.
So I was not told the high pressure coolant pump needed a separate power cord, until the last min. So I had to scramble and used a different phase converter for that connection. Everything worked fine. So last week I hooked that pump up to the same converter...not fine. It drooped the voltage and immediately alarmed out the control.
Loooong story short the generated leg needs to go to the far right (L3). Now everything is warm and fuzzy
Gary
I know I am. Mine was wrong..and it does matter.
When I went to take the pictures for this thread I noticed that the machine breaker was not numbered..
So I was not told the high pressure coolant pump needed a separate power cord, until the last min. So I had to scramble and used a different phase converter for that connection. Everything worked fine. So last week I hooked that pump up to the same converter...not fine. It drooped the voltage and immediately alarmed out the control.
Loooong story short the generated leg needs to go to the far right (L3). Now everything is warm and fuzzy
Gary
What's the horse power on your converter?
Mike
Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28
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