isolated Tx - no service neutral

[GITRDUN]

140813-2138 EDT

GITRDUN:

The HAAS large main disconnect is also a breaker. Look at the disconnect's handle and you will see the ampere rating.

Youre right. They are breakers. Never had a main disconnect trip, guess thats a good thing.

I stopped by the shop on my way through town tonight and checked what type of breakers the machines have. All of them that i checked in multiple machines dont have a tripped state,they are either on or off.

 

[iceworm]

visibility post

visibility post

post for visibility

 

[gar]

140815-0913 EDT

GITRDUN:

I believe your troubleshooting idea was to power down the CNC, open the disconnect, check the state of the breakers, put all breakers in the off state, close the cabinet door, and in the morning see if anything failed.

I do not believe most, if any, of the breakers isolate the circuit areas where your failures have occurred. In my post numbered 36 the listed small breakers are for coolant pump, another motor, user outlet, solenoids, etc.

None of these have anything to do with the AC side of the servo motors or main spindle. One breaker relates to the solenoids. The servo motors and main spindle appear to be limited only by the main disconnect/breaker.

Since you have indicated that one or more of the small breakers have tripped, possibly in association with other failures, then it is important to know which breakers tripped.

A useful experiment would be to have the cabinet door open at the time the machine was powered down. I don't know how to open the door with the disconnect on. Were the disconnect a Sq-D, then it is easy. If there is no way to override the mechanical interloack, then the only way is to open the door close the disconnect, mostly close the door, and run with the door just open a crack. It would be important to know if any of the breakers trip at the time CRM drops out. Any failure before power down would cause the machine to not function, and this has not been mentioned.

By any chance were line reactors added to the 3 phase input lines to the machines?

.

 

[iceworm]

bump for visibility (again)

What do I need to do to see these? I've changed the settings from default to forty - and several in between. No change.

ice

 

[gar]

140815-1040 EDT

iceworm:

What are the "these" that you want to see?

.

 

[kwired]

Im pretty sure most if not all of the machines breakers dont have a tripped state, they are either flipped on or off. I will double check to make sure thats correct however and post back later.

The large main disconnects do not have a breaker, they are just a simple disconnect switch.

We shut machines off by pushing the control off button, then going to the back side of the machines and flipping the main disconnect switch to the off position. Power up is reverse. This is standard for any CNC machine ive ever seen no matter what model or year it was. The main disconnects are built into the machines.

Since you are turning off this main disconnect that has no overcurrent protection, you certain transformer inrush isn't what is tripping your breakers when you first energize the machine?

bump for visibility (again)

What do I need to do to see these? I've changed the settings from default to forty - and several in between. No change.

ice

Just a glitch that seems to randomly happen here.

 

[GoldDigger]

140815-1040 EDT

iceworm:

What are the "these" that you want to see?

.

I am sure that he was suffering from the chronic intermittent problem with page rollovers. He could not get the next page containing post #41 to show up in his browser until after he added another post. Changing his setting for the # of posts per page to anything else and changing it back again would also, I think, have resolved his problem in a less intrusive but more tedious way.

 

[GITRDUN]

140815-0913 EDT

I believe your troubleshooting idea was to power down the CNC, open the disconnect, check the state of the breakers, put all breakers in the off state, close the cabinet door, and in the morning see if anything failed.
.

#1. Not trying to see if anything failed with the breakers off. Trying to see if the failures go away or change with the breakers off.

#2. By having my employees switch off the breakers after they turn off the main disconnect then we will know immediately if one of the breakers tripped off when the disconnect was switched off. If a breaker trips off while the machine is on the machine will throw up an alarm, you would know it right away.

#3. Ive said this many times now but ill say it again. One week ago i found at least 4 machines that had breakers inside the machine tripped to the off position before any machinery was turned on that morning. All of these machines were running the day before when they were switched off for the day. This tells me that the breakers are not getting tripped when they are turned on but instead are tripping out when it is turned off (or possibly during the night which is highly unlikely but possible).

To me the breakers getting tripped is pointing a finger to what exactly our problem is. I have no doubt the tripped breakers are related to whatever is blowing our electronics boards.

 

[GITRDUN]

Since you are turning off this main disconnect that has no overcurrent protection, you certain transformer inrush isn't what is tripping your breakers when you first energize the machine?

No im not sure, but from finding machines with breakers tripped before the main disconnects are even switched on tells me this is happening either at the time of the main disconnect being switched off or over night. Every day im hoping we catch one in the act, but hasnt happened yet. It will, just a matte of time.

 

[Little Bill]

No im not sure, but from finding machines with breakers tripped before the main disconnects are even switched on tells me this is happening either at the time of the main disconnect being switched off or over night. Every day im hoping we catch one in the act, but hasnt happened yet. It will, just a matte of time.

I'm following this thread and am getting more confused as it goes along. You, or maybe you and someone else stated that the breakers inside the machine did not have OCP. They were just either on/off by manually switching them. If that's the case, how could they be tripping?
Or did I miss something?:?

 

[kwired]

I'm following this thread and am getting more confused as it goes along. You, or maybe you and someone else stated that the breakers inside the machine did not have OCP. They were just either on/off by manually switching them. If that's the case, how could they be tripping?
Or did I miss something?:?

His main disconnect doesn't have overcurrent protection, but there are multiple overcurrent devices within the machine - is what I am understanding. At the end of the day he is turning the machine off via operator controls, as much as they shut things down anyway, then opening the main disconnecting means.

 

[gar]

140815-2111 EDT

GITRDUN:

In all of our HAAS machine, except possibly one, there is no load connected directly to the output of the main disconnect/breaker, except the small amount of circurity that controls the CRM relay coil, and the input side of the CRM contacts.

This very small load is from 230 and certainly less than 1 A. Suppose there was 10 W of transformer loss. This would amount to about 0.05 A of current thru two legs of the disconnect, and nothing thru the third leg.

Opening the disconnect with this amount of current would hardly damage most items in HAAS. But there is nothing in HAAS connected at this time because CRM is already open at the time of opening the disconnect based on your described shut down procedure, and that is the procedure we usually use.

Opening of the disconnect should not be the time when failures occur. Rather opening of CRM (machine power down) is the likely time, if this is the cause.

.

 

[iceworm]

Switched to 40 posts (again) - I can see now.

... Every day im hoping we catch one in the act, but hasnt happened yet. It will, just a matte of time.

git -
Let me reword what I think you ae saying to do for a test.

Every night:

• Turn off machine
• Check that the small cbs (the ones that are tripping) are in normal running position - Closed - none have tripped (or turned off)
• Turn off main disconnect
• Check small CBS. If any have tripped, troubleshoot what could have happened - As in set up power monitoring equipment.

If Not

• Leave cbs closed for the night
• In the morning, check CBs - I highly suspect none will be tripped. If any are tripped, set up a camera.
• Close disconnect
• Check the small cbs. If any have tripped, troubleshoot what could have happened - As in set up power monitoring equipment.

Repeat until tired of checking.

My guesses (in order of probability):

1. None will trip all the time you are monitoring. Trips will start again after you stop monitoring. In this case you will need a hidden camera.
2. You could have a bunch of CBs that are subject to minor spikes (old, wore out, tired, used as switches. In this case the trips will be happening on Disconnect Close in the morning.
3. I really don't know of anything that could cause the CBs to trip on Disconnect Opening.
4. Be that as it may, if you do find them tripping on Disconnect Opening - it is something really weird. You will need decent monitoring equipment. And you wil need a tech to help out. Is maybe one of your mechanics up on this kind of stuff? Hope so. It willbe difficult to hire someone just to do the monitoring - especially if it is an intermittent.
5. If the trips do happen at night while the disconnect is open, suggest a hidden camera first, monitoring equpment second

I'm guessing you were already aware of all of this.

ice

 

[GoldDigger]

I'm following this thread and am getting more confused as it goes along. You, or maybe you and someone else stated that the breakers inside the machine did not have OCP. They were just either on/off by manually switching them. If that's the case, how could they be tripping?
Or did I miss something?:?

Close. What he said was that the handle of the breakers in the machine did not have a midpoint "tripped" position. So the appearance would be the same if they tripped on OC or were turned off manually.

 

[gar]

140815-2140 EDT

kwired:

The main disconnect/breaker is a breaker and is the only OCP for the high power loads (main spindle and servo drives).

Under normal operating procedure there is never much current flow thru the main disconnect/breaker when it is closed or opened. Above I estimated 50 mA (0.05 A). High current can only flow when CRM is energized, and in the normal start up and shut down procedure CRM is open when the disconnect is opened or closed.

.

 

[GITRDUN]

git -
Let me reword what I think you ae saying to do for a test.

Every night:

• Turn off machine
• Check that the small cbs (the ones that are tripping) are in normal running position - Closed - none have tripped (or turned off)
• Turn off main disconnect
• Check small CBS. If any have tripped, troubleshoot what could have happened - As in set up power monitoring equipment.

If Not

• Leave cbs closed for the night
• In the morning, check CBs - I highly suspect none will be tripped. If any are tripped, set up a camera.
• Close disconnect
• Check the small cbs. If any have tripped, troubleshoot what could have happened - As in set up power monitoring equipment.

ice

Correct. It eliminates any guessing as to when exactly the problems are occurring.

 

[GITRDUN]

140815-2111 EDT

Opening of the disconnect should not be the time when failures occur. Rather opening of CRM (machine power down) is the likely time, if this is the cause.
.

I agree. But we have the exact same problem occurring in other machines that are not Haas brand are wired entirely differently. In the Haas specifically the only breaker that trips is the main Tx breaker. When one machine has a breaker tripped there is almost always another machine or two that will also have one tripped. It comes and goes but it seems to usually come in multiples when it happens.

 

[Little Bill]

Close. What he said was that the handle of the breakers in the machine did not have a midpoint "tripped" position. So the appearance would be the same if they tripped on OC or were turned off manually.

I will admit it confuses me when Gar is talking about only one brand of machine and the OP has something different. I may have been guilty of "skimming" some posts but the following, with it's wording, is what made me think the breakers were only on/off with no OCP.

Im pretty sure most if not all of the machines breakers dont have a tripped state, they are either flipped on or off. I will double check to make sure thats correct however and post back later.

 

[p real]

Any other circuits connected to the machines? E stops? other control ckts of any kind?

 

[gar]

140815-2347 EDT

Little Bill:

GITRDUN has about 6 HAAS machines for CNC mills, and lathes that are Okuma. I can only talk in detail about the HAAS machines because we have 6 of them.


GITRDUN:

If only the "Main Circuit Breaker" in HAAS is tripping, then this only relates to loads on the secondary side of the 3 phase transformer.

This breaker is variously:

The following use DC servos. Brush type motors.
1993 machine --- 25 A, 115 V, 3 phase
1995 machine --- 25 A, 115 V, 3 phase

The following are brushless servos.
1996 machine --- 10 A, 115 V, 1 pole
2000 machine --- 10 A, 115 V, 1 pole

This breaker probably supplies the computer power supply and you have indicated that nothing fails in the computer area. What else is supplied from this breaker I don't know.

What specific components are failing in the HAAS machines?

If an excessive amount of series inductance exists in the source feeding the CNC machine, and combined with the transformer series inductance, then opening CRM while there is moderate current flow may cause some very large short voltage spikes.

.