The Home Machinist!

John Hasler wrote: ↑Sat Jun 09, 2018 7:53 am Single phasing with no motors running should not have harmed the electronics but the spike may have. It's possible that the fuses did their job and protected the machine from further damage. I'd determine what the fuses protected, inspect for visible damage, and if I found none replace the fuses and try again. Are the fuses in the AC side? Do you have documentation?

I did the "replace the fuses and try again" thing the moment I found them blown, and had high hopes that there was no further problem, but as I stated in another post in this thread, when the second one was replaced, both blew again. That tells me that something was damaged when the problem arose. I am only speculating that the induction furnace was the cause, as I have no idea when the machine died. It was fine about a year ago, when I fired it up so I could make a copy of the operating system in case I had a battery fail.

It is unusual for us to get lightning in this area. Where I resided in Utah, that was not the case. I can pretty much dismiss lightning as the problem as a result, and the only thing that I can think of would be the blown fuse on the primary side of my service. We've had several power outages, too, so I assume I can't dismiss them as a possible cause, although we've had many previously, all with no problems resulting. How I wish I had not left the panel live. This problem may not have occurred, but I guess I'll never know.

I haven't spent any time looking at this thing, so I don't know that I can answer the question as to the fuses being on the AC side, but I believe they are. I have full documentation on the machine, but I'm not convinced they provide schematics for one to troubleshoot. I certainly don't recall seeing any, but then I wasn't looking for them, either. I was too involved in trying to learn operational procedures to worry about that---and it's been too long for me to remember anything more. When I am ready to tackle the repair, I'll take a second look. Mean time, I have a lot to do, so it's on the back burner for now.

Thanks for your thoughts, John.

H

Nothing to do now but hope that the fuses are on the AC side and that it's a power supply problem (because power supplies are easier to troubleshoot and repair).

Hello everyone,
I agree you need to exercise (not exorcise even though some days it seems necessary) your CNC machine or it seems to get stiff and cranky that's why my router needed and received a new control when I shipped over here. Sort of like us old guys. The Fanuc GN5 fuses were rebuild able but I searched an it seems the Hass ones are different. I found a on-line manual that might help you...

https://diy.haascnc.com/sites/default/f ... y_2010.pdf

I sort of like the tag "Remember if you cant fix it with a hammer it must be an electrical problem."

be safe
Karel

Karel,
Thanks for that link. I've already taken a look and found I may have to address the voltage settings, which may be responsible for the failure. I'm not sure that's the case, as the machine ran for a long time as wired, but that doesn't mean it's not the problem. Voltage, here, has been known to vary.

The machine may have been wired Star when it was owned previously. I have Delta service, which is about 15% higher voltage. I won't take a look at this thing for a few days, as I'm on the heels of finishing the setup to generate the worm, which I'd like to get finished. I'll report my findings when I get to the machine, though.

To be clear, I didn't have a copy of that manual, so it's very welcome. It describes the board quite nicely, although mine is located somewhat differently. My machine was built in 2004, as I recall, which may be the reason for the difference.

As you alluded, the Haas fuses are different. They're smaller in diameter than those with which I'm familiar, and of which I have a generous supply. I'll attempt to get more, as I'm down to just one now, with two blown. All in good time, I say!

H

Hi Harold,
Glad to be of help.
Karel

Star or Delta on home service? How do I tell or should I not worry?

Best way to tell is to ask the power company. You could also measure the voltage.

https://ctlsys.com/support/electrical_s ... _voltages/

Based on my limited experience, if you have 208 volts, that's Star. 240 is Delta. Both yield 120 volts to neutral, however. Star is generally used where there's a higher light load, not as common for machine tools, but it does exist in such facilities. I am open to correction if I've said something stupid. I'm not an electrician.

I've always had Delta service to my shop, and even the residential side of the castle when we built it. I chose to wire three phase panels in the house as it helped me get the three phase service to a residence free of charge by guaranteeing use. We had two heat pumps, although only single phase (240 volts). I made sure they were wired to opposite phases (one A-B, the other B-C). They did not install a demand meter. Why, I do not know, as I have one here. Different state, different rules, I guess.

The negative aspect of having Delta service is the three phase panel loses one space out of three if you must provide 120 volts. The B phase reads 208 volts to ground (or neutral) because ground is center tapped on the B coil. Make sense? Because of that, I have dual service in my shop, one three phase panel, one single phase panel. Both are almost full.

H

Harold writes:
>The B phase reads 208 volts to ground (or neutral) because ground is center tapped on the B coil.

Not always. There is ungrounded delta (usually seen in industrial facilities) and corner-grounded delta where the B phase is grounded.

Both yield 120 volts to neutral

The reason for the "blanked off" spots is that the "Wild Leg" of 208 does not produce 120 volts to ground. So you should not put a single breaker in those slots!

Quick way to tell if you have 208 Wye or 240 Delta is to go out and look at the transformers on the pole. If you only have two then you are most likely 208 with a wild leg. If you have three transformers, then you are delta with 240 volts. All legs to ground on a delta panel will yield 120 volts! (there are exceptions)


So the big reason for 208 was the cost to install! Two transformers were cheaper than three so the power company did 208 a lot back in the day. Not so much today as the wild leg thing gets people in trouble!

I actually ran into a circuit in Catoosa Oklahoma that was a 440 volt 3 phase circuit for the main AC unit at a country club. Two legs would measure 440 volts to ground and the center leg measured -0- volts to ground but phase to phase they all measured 440 volts. No one could ever tell me what type of setup that one was. And I never ever ran into another one in all the years I worked around commercial buildings.

Dave C.

I'm not sure your information is correct. The reason I say that is that I had an open Delta setup for my first shop. In an open Delta, there's only two transfomers. Voltage remains the same (240 phase to phase, 120 phase to neutral from both A&C, 208 volts from B to neutral) but you're limited to running light loads. I was fine running my 5 horse compressor, but anything larger would have been questionable. The other services (two of them) since then were Delta, with three transformers. The high leg (208 volts) is due to the fact that that phase (B) to ground uses all of one coil and half of another. I don't fully understand the math in figuring the voltage, but I know that it measures 208. I have such a system.

Voltage to neutral, or ground, is determined by where ground is attached at the transformer, and it isn't variable, as it's how they're wound. To my knowledge, you can't get 208 from a Delta phase to phase, and you can't get 240 from a Star (Wye), as they're not wound to do so, assuming the primary voltage is the same in both instances. You certainly could achieve any of those values if you had the option to vary the primary voltage.

I'm not an electrician, so I may be confused on what I've said, above. Here's a link that might be helpful. https://www.electronics-tutorials.ws/tr ... ormer.html

H

Dave_C wrote: ↑Wed Jun 13, 2018 9:05 am

Both yield 120 volts to neutral

The reason for the "blanked off" spots is that the "Wild Leg" of 208 does not produce 120 volts to ground. So you should not put a single breaker in those slots!

Quick way to tell if you have 208 Wye or 240 Delta is to go out and look at the transformers on the pole. If you only have two then you are most likely 208 with a wild leg. If you have three transformers, then you are delta with 240 volts. All legs to ground on a delta panel will yield 120 volts! (there are exceptions)

Open delta is usually 240 phase to phase: it's produced by wiring up two 240V residential pole pigs. If it is the usual "open delta high leg" configuration you will see 208V from the grounded center tap to the high leg.

In a full delta system with 240V phase to phase the phase to (virtual) neutral voltage will be 138V. A real neutral for such systems can be synthesized with a zig-zag transformer. Of course, it may be wired up with a grounded center tap. Then it's a "closed delta high leg" and differs from "open delta high leg" only in having more capacity.

I actually ran into a circuit in Catoosa Oklahoma that was a 440 volt 3 phase circuit for the main AC unit at a country club. Two legs would measure 440 volts to ground and the center leg measured -0- volts to ground but phase to phase they all measured 440 volts. No one could ever tell me what type of setup that one was. And I never ever ran into another one in all the years I worked around commercial buildings.

That was corner grounded delta. Instead of leaving it floating or using a zig-zag to generate a neutral and grounding that they simply ground the B phase.

Note: grounding a conductor in a three-phase system does *not* make that conductor the neutral! Unless that conductor is the real three-phase neutral it is just a grounded current-carrying conductor and should not be identified as a neutral.