- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I read that they are either in the flipped on position or the either *flipped or tripped* off position
isolated Tx - no service neutral
- Thread starter GITRDUN
- Start date
- Status
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
I don't recall ever seeing a breaker with no "tripped" position. I may have in a control cabinet but didn't realize it.
I'll just stick to reading because I'm not able to aid in the remedy and I don't want to "muddle" up this thread any further with my misunderstandings!
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
140816-0916 EDT
Little Bill:
Do not stop participating. When you do not understand something, then many others may have the same problem or questions. Your participation will probably help you as well as others.
Asking questions from many different points of view may help finding the correct question to ask.
In the subject of this thread there are various CNC machines apparently showing similar failures. Machines bought from the same manufacturer at different times may not be identical, but may have some commonality that relates to the problem. How does any commonality relate?
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Little Bill:
Do not stop participating. When you do not understand something, then many others may have the same problem or questions. Your participation will probably help you as well as others.
Asking questions from many different points of view may help finding the correct question to ask.
In the subject of this thread there are various CNC machines apparently showing similar failures. Machines bought from the same manufacturer at different times may not be identical, but may have some commonality that relates to the problem. How does any commonality relate?
.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
This is true with breaker types commonly used in panelboards and the molded case counterparts from the same production lines. All made to NEMA standards for the most part. Some of your control panel units may not be designed this way. Those are often made to IEC or other standards. I could be wrong and have no real facts to back that up with, is just kind of my observation though.I don't recall ever seeing a breaker with no "tripped" position. I may have in a control cabinet but didn't realize it.
I'll just stick to reading because I'm not able to aid in the remedy and I don't want to "muddle" up this thread any further with my misunderstandings!
iceworm
Curmudgeon still using printed IEEE Color Books
- Location
- North of the 65 parallel
- Occupation
- EE (Field - as little design as possible)
My understanding is there are small CBs that are reacting eratically. Is this main CB different that the other small cb? If different, does it have a "tripped" position? If it does, is it tripped or OFF?
icef
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
140816-1113 EDT
iceworm:
In the HAAS machines:
The true MAIN breaker is the disconnect/breaker that is generally 30 to 40 A at 230 V 3 phase, and higher on some machines. Half that in 460 V machines.
This other breaker that has the word MAIN as part of its name is a small 115 V breaker, 3 pole or 1 pole depending upon the year of manufacture, rated at 25 or 10 A. This breaker is on the output side of the main 3 phase transformer, not the input side that is a nominal 230 V. This small breaker does not have a tripped point different than its off position.
That this breaker is named Main Transformer is a misleading label. Since it is on the output side of the transformer it should have a name relating its loads.
Normally these small breakers will not just randomly trip, especially when considered across a number of machines.
I believe the computer power supply is a load on this 115 V breaker, and in older machines the servos may have been fed from it. A question to ask is: Are there MOVs in the loads that might trip this breaker on minor over-voltage that would not cause CRM to drop out? Also has every HAAS machine experienced the subject problem at some time or other, or only certain ones? On the HAAS machines are there component failures or just breaker tripping events?
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iceworm:
In the HAAS machines:
The true MAIN breaker is the disconnect/breaker that is generally 30 to 40 A at 230 V 3 phase, and higher on some machines. Half that in 460 V machines.
This other breaker that has the word MAIN as part of its name is a small 115 V breaker, 3 pole or 1 pole depending upon the year of manufacture, rated at 25 or 10 A. This breaker is on the output side of the main 3 phase transformer, not the input side that is a nominal 230 V. This small breaker does not have a tripped point different than its off position.
That this breaker is named Main Transformer is a misleading label. Since it is on the output side of the transformer it should have a name relating its loads.
Normally these small breakers will not just randomly trip, especially when considered across a number of machines.
I believe the computer power supply is a load on this 115 V breaker, and in older machines the servos may have been fed from it. A question to ask is: Are there MOVs in the loads that might trip this breaker on minor over-voltage that would not cause CRM to drop out? Also has every HAAS machine experienced the subject problem at some time or other, or only certain ones? On the HAAS machines are there component failures or just breaker tripping events?
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Yes every Haas brand machine i have has and does experience this problem. Sometimes you find would find a breaker tripped and that was it, and sometimes there would be a blown board to accompany the tripped breaker. The oldest is a '94 model which has brushed axis motors and the newest machine we have is an '08 model.
And yes there are component failures on all of them. On the Haas specifically the components that fail are the main I/O PC board which is sort of a break out board for all components of the machine except the servo motors and spindle drive. Also the spindle drive control boards get hammered. These are the only two components that get damaged on the Haas machines. The logic control boards never get damaged.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
140817-21027 EDT
GITRDUN:
With your above information I will look at the HAAS diagrams and see if there is any logical indication of what happens.
Since only the "Main Transformer" breaker is tripping (secondary side of main transformer) this means that something on the load side of that breaker is causing or allowing a large current. This is a 20 or 10 A breaker at 115 V, possibly a fast trip, compared to the 30 A or larger and possibly slower trip main breaker at 230 V. Because of the two to one transformer ratio the 20 A at 115 V becomes 10 A at 230 V.
That the input MOV over voltage circuit is not blowing its fuses (1/2 A non-slowblow) means that peak voltage at the CRM relay is not exceeding about 400 V. But over voltage at the tripping breaker is implied.
What is your highest steady state line-to-line voltage that exists at the machine inputs? Ours generally runs about 250 V. Our supply is a 240 V open delta with about 350 ft of 0000 copper from the transformer to our main panel.
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GITRDUN:
With your above information I will look at the HAAS diagrams and see if there is any logical indication of what happens.
Since only the "Main Transformer" breaker is tripping (secondary side of main transformer) this means that something on the load side of that breaker is causing or allowing a large current. This is a 20 or 10 A breaker at 115 V, possibly a fast trip, compared to the 30 A or larger and possibly slower trip main breaker at 230 V. Because of the two to one transformer ratio the 20 A at 115 V becomes 10 A at 230 V.
That the input MOV over voltage circuit is not blowing its fuses (1/2 A non-slowblow) means that peak voltage at the CRM relay is not exceeding about 400 V. But over voltage at the tripping breaker is implied.
What is your highest steady state line-to-line voltage that exists at the machine inputs? Ours generally runs about 250 V. Our supply is a 240 V open delta with about 350 ft of 0000 copper from the transformer to our main panel.
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Well it got another machine today. Was one of the Haas mills. Blew a resistor on the main IO PC board that is in the cuircut for powering the micro switches, the same board that always gets smoked. I personally checked to make sure breakers were in the off position on that machine at the end of shift Friday. This morning the operator opened the back cabinet, flipped on all breakers, then turned on the main disconnect and powered the machine up as normal. When it came on there were multiple alarms. And no breakers had been tripped. We promptly found the bad resistor and put it back in service. Cant say positively this wasnt just an old component that was ready to go but who knows. It was the only machine that had any trouble.
Still waiting for somebody to catch one tripping a breaker at switch off.
Still waiting for somebody to catch one tripping a breaker at switch off.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Though it probably wouldn't have much to do with breakers mysteriously tripping, have you looked into what if any harmonic problems you may have at your facility? Failing components because of harmonics could cause breaker tripping, but you should have a unit that doesn't function properly after resetting.
Also do you have power factor correction capacitors at your facility?
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Harmonics is distortion of the normal sinusoidal current/voltage wave, it is caused by semiconductors in electronic equipment trimming those waves during high speed switching operations. You likely have some harmonic distortion, just in common electronic devices, electronic lighting ballasts, LED lighting, and a bigger one may just be drives on your CNC machines or even other machines you may have with variable speed drives.
Sometimes certain equipment is effected by the "dirty" power that those harmonics leave in the system, and can have problems that are hard to figure out until someone that understands the harmonic problems better steps in and says "this is your problem, I have dealt with this before"
I don't claim to be a harmonics expert, but have some basic understanding. I am not the one that would step in and say "here is your problem" but would step in and say "this could be your problem". I have also heard of capacitors compounding some harmonic problems. Whether or not you have PF correction usually depends on if your POCO penalizes you for having low power factor, if they don't it usually isn't worth the cost to correct it. If you don't have a lot of motor load you likely don't have low power factor anyway.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
140819-0850 EDT
GITRDUN:
With reference to your post #69.
More information is needed.
What specific breaker tripped? What resistor failed? What was the resistance, power rating, and type of resistor? Where is the resistor in the circuit?
The "IO PC board" has many functions.
The one line drawing shows 230 V and 115 V inputs. These can not have a common connection because they come from opposite sides of what amounts to a 3 phase delta to delta. I believe the secondary delta is un-grounded. The primary side delta is only grounded by the power source to the machine.
Also on this board are limit switch inputs. In our 93 machine each limit switch is between a ground symbol (means machine frame and ultimately the machine input EGC) and its own pull-up resistor to +5 V. This then would go to the input of a TTL type logic gate. This resistor is probably 390 to 1000 ohms rated 1/4 W, and is possibly carbon comp. In the 2000 machine the pull-up voltage is +12 V and possibly 560 to 1000 ohms and the input of an optical coupler like a 4N35. I really doubt that one of these resistors failed with out other damage.
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GITRDUN:
With reference to your post #69.
More information is needed.
What specific breaker tripped? What resistor failed? What was the resistance, power rating, and type of resistor? Where is the resistor in the circuit?
The "IO PC board" has many functions.
The one line drawing shows 230 V and 115 V inputs. These can not have a common connection because they come from opposite sides of what amounts to a 3 phase delta to delta. I believe the secondary delta is un-grounded. The primary side delta is only grounded by the power source to the machine.
Also on this board are limit switch inputs. In our 93 machine each limit switch is between a ground symbol (means machine frame and ultimately the machine input EGC) and its own pull-up resistor to +5 V. This then would go to the input of a TTL type logic gate. This resistor is probably 390 to 1000 ohms rated 1/4 W, and is possibly carbon comp. In the 2000 machine the pull-up voltage is +12 V and possibly 560 to 1000 ohms and the input of an optical coupler like a 4N35. I really doubt that one of these resistors failed with out other damage.
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No breakers were tripped in the machine. The resistor that blew was an R-Pack, .25watt, 10 pin, 10k. Thats the info i got from my maintenance man. I dont know what voltage it is but it is part of the cuircut for the limit switches on the spindle transmission and tool magazine. Aparently thats the only thing that blew, or at least thats all that he found wrong with it, once the resistor was changed everything has worked fine since.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Has there been any pattern of these machines blowing that same resistor nearly every time there is a problem, or are the problems more random?
Same pattern of problems and you maybe have a better chance of narrowing down a cause.
It has been nearly 20 years ago but at a facility I once worked at we had problems with a new (to the facility) cheese packaging machine they just installed. It was a carousel type of machine that rotated and had several stations. We kept blowing sealer heater elements in this machine. After a lot of investigating and calling other "experts" we finally figured out that harmonics in the supply system were messing with the control boards for these heaters, and in particular harmonics from a large VFD located in another part of the plant, which explained why some days we had no trouble at all - that drive wasn't running on those days.
First time we have had that cuircut blow. Specifficly on the Haas machines the usual thing that blows on the IO/PC board is the cuircuts which control the solenoid valves for various things. Usually they blow up the mosfets , electronic relays, and voltage regulators in one solenoid valves cuircut. And occasionally it will also burn a trace on the board. Its not always the same valves cuircut that gets hit.
The electronic components on the IO/PC boards change from one year to the next and the board design and layout has changed a bit over the years, however one years parts are usually almost exact replacements for the previous years parts. That is to say that although the different year model of machines have different electronic components on the board the basic design and layout of each cuircut is practically the same. Hope im not making this sound more confusing, im not to good with explaining things.
The electronic components on the IO/PC boards change from one year to the next and the board design and layout has changed a bit over the years, however one years parts are usually almost exact replacements for the previous years parts. That is to say that although the different year model of machines have different electronic components on the board the basic design and layout of each cuircut is practically the same. Hope im not making this sound more confusing, im not to good with explaining things.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
140820-1000 EDT
GITRDUN:
You did not indicate the year of the machine.
Almost certainly these are pullup resistors. Because they are 10 K and in a multi-resistor package. I suspect it was an early machine before they isolated the logic gates from the limit switches with optical couplers. In those machines pullup was to +5 V. This resistor is between a logic gate input and +5 V, and the limit switch pulls the logic gate to 0 V when closed. Max power dissipation per resistor is 25/10,000 = 2.5 milliwatts. That resistor will never fail from the normally applied power. To have a high voltage applied to the resistor that would cause failure almost certainly would damage the logic gate. Is there other protection at the logic gate input? I don't know.
To damage a 10 K 0.25 W resistor will probably require 1 W for milliseconds. To produce 1 W in 10,000 ohms requires 100 V.
This was not a good design for several reasons, but we have never had a problem in this area with the our early machines.
Were this a newer machine with the optical couplers, then the resistor would need to be much lower. In this case the pullup voltage is +12 V, and an optical coupler, like the 4N35, would probably be driven by about 10 mA requiring about 1000 ohms for pullup.
Resistors and transformers run below their maximum ratings typically have very long lives. Easily more than 50 to 100 years.
This failure does not seem to fit the pattern you have generally described. Your description implies that the failure did not occur while the machine was powered, but may have occurred at power down.
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GITRDUN:
You did not indicate the year of the machine.
Almost certainly these are pullup resistors. Because they are 10 K and in a multi-resistor package. I suspect it was an early machine before they isolated the logic gates from the limit switches with optical couplers. In those machines pullup was to +5 V. This resistor is between a logic gate input and +5 V, and the limit switch pulls the logic gate to 0 V when closed. Max power dissipation per resistor is 25/10,000 = 2.5 milliwatts. That resistor will never fail from the normally applied power. To have a high voltage applied to the resistor that would cause failure almost certainly would damage the logic gate. Is there other protection at the logic gate input? I don't know.
To damage a 10 K 0.25 W resistor will probably require 1 W for milliseconds. To produce 1 W in 10,000 ohms requires 100 V.
This was not a good design for several reasons, but we have never had a problem in this area with the our early machines.
Were this a newer machine with the optical couplers, then the resistor would need to be much lower. In this case the pullup voltage is +12 V, and an optical coupler, like the 4N35, would probably be driven by about 10 mA requiring about 1000 ohms for pullup.
Resistors and transformers run below their maximum ratings typically have very long lives. Easily more than 50 to 100 years.
This failure does not seem to fit the pattern you have generally described. Your description implies that the failure did not occur while the machine was powered, but may have occurred at power down.
.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
140820-1327 EDT
GITRDUN:
As an experiment I would try a transient limiter on the secondary side of the main transformer on the output of what is labeled "Main Transformer" breaker..
Nominal secondary line-to-line voltage is 115 V. This is a peak of 162 V. A 200 V peak results from a 141 V RMS sine wave. I would put a bi-directional transient limiter between each of the secondary lines coming from the breaker.
Because I would like a tight sharp clipping curve I would experiment with a Transorb. What is available might be marginal, but this would be an experiment. The highest voltage and peak power Transorb made by Vishay is a uni-directional 5KP188A. Two of these can be put in series back-to-back to make a bi-directional limiter.
The other direction is to search for an MOV. Its clamping curve won't be as sharp.
The goal with the experiment would be to protect the circuit components, and expect to trip the circuit breaker.
Your problem description based on the failed components implies a voltage spike. Where and why that spike occurs needs to be determined.
Your 10 K resistor failure is likely an internal machine problem. Possibly a cable failure letting motor power get to a limit switch circuit.
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GITRDUN:
As an experiment I would try a transient limiter on the secondary side of the main transformer on the output of what is labeled "Main Transformer" breaker..
Nominal secondary line-to-line voltage is 115 V. This is a peak of 162 V. A 200 V peak results from a 141 V RMS sine wave. I would put a bi-directional transient limiter between each of the secondary lines coming from the breaker.
Because I would like a tight sharp clipping curve I would experiment with a Transorb. What is available might be marginal, but this would be an experiment. The highest voltage and peak power Transorb made by Vishay is a uni-directional 5KP188A. Two of these can be put in series back-to-back to make a bi-directional limiter.
The other direction is to search for an MOV. Its clamping curve won't be as sharp.
The goal with the experiment would be to protect the circuit components, and expect to trip the circuit breaker.
Your problem description based on the failed components implies a voltage spike. Where and why that spike occurs needs to be determined.
Your 10 K resistor failure is likely an internal machine problem. Possibly a cable failure letting motor power get to a limit switch circuit.
.
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