big denford triac problems

[mark35gun]

hi all, i have just purchased a denford triac fanuc m/c after many years on a bridgeport interact with hh tnc 151.
so to cut a long story short i got it with a rotary phase converter as i have not got 3 phase at home, but i will have it when i move the m/c into my premises when i am ready, so i started the m/c and messed around a little bit ran a programme for a short while all seemed ok, when i turned off the rotary converter the ammeter on it spiked to over an indicated 30amps, i switched everything off, but not before it fried the z axis amp and an input unit, so i managed to get two replacements from the bay this weekend and carefully fitted them, i checked the m/c before power on thoroughly and could find nothing obvious, so i powered the m/c again, the control turned on and came up with 4 errors one servo overload and ones for x,y,z, these boards showed a low voltage led lit, i was unable to clear these so i started fault finding, i caught the contactor overload reset button in the rotary convertor while the m/c was on and it immediately showed a pull of 30 amps and fried the z amp board i had just fitted and the x,y axis boards as well.
i cannot keep throwing money at it but do need a m/c of this nature, so now i will be into it for at least another £1200, does anyone know of a fanuc engineer who would visit to repair the m/c?
it really needs someone with more experience on repairing the control side than me, or do i sell it and cut my losses and replace it with another working triac?
any advice appreciated, as i am now starting to pull my hair out or what little i have left
the control is fanuc omb if that helps.
i now don't know whether there is a fault with the phase convertor or an unfound problem with the control although the rotary phase convertor output meters ok i think.
advice/help please anyone?
mark.

[m_c]

when i turned off the rotary converter the ammeter on it spiked to over an indicated 30amps, i switched everything off,

Ammeter on what?


And what rotary phase converter are you using? One you've bought, or one you've made?

[Chaz]

hi all, i have just purchased a denford triac fanuc m/c after many years on a bridgeport interact with hh tnc 151.
so to cut a long story short i got it with a rotary phase converter as i have not got 3 phase at home, but i will have it when i move the m/c into my premises when i am ready, so i started the m/c and messed around a little bit ran a programme for a short while all seemed ok, when i turned off the rotary converter the ammeter on it spiked to over an indicated 30amps, i switched everything off, but not before it fried the z axis amp and an input unit, so i managed to get two replacements from the bay this weekend and carefully fitted them, i checked the m/c before power on thoroughly and could find nothing obvious, so i powered the m/c again, the control turned on and came up with 4 errors one servo overload and ones for x,y,z, these boards showed a low voltage led lit, i was unable to clear these so i started fault finding, i caught the contactor overload reset button in the rotary convertor while the m/c was on and it immediately showed a pull of 30 amps and fried the z amp board i had just fitted and the x,y axis boards as well.
i cannot keep throwing money at it but do need a m/c of this nature, so now i will be into it for at least another £1200, does anyone know of a fanuc engineer who would visit to repair the m/c?
it really needs someone with more experience on repairing the control side than me, or do i sell it and cut my losses and replace it with another working triac?
any advice appreciated, as i am now starting to pull my hair out or what little i have left
the control is fanuc omb if that helps.
i now don't know whether there is a fault with the phase convertor or an unfound problem with the control although the rotary phase convertor output meters ok i think.
advice/help please anyone?
mark.

Its fairly easy to convert a Triac to single phase. On mine, the only thing actually running on 3 phase (once you look at the drawings) was the monitor and the coolant pump.

[mark35gun]

Its fairly easy to convert a Triac to single phase. On mine, the only thing actually running on 3 phase (once you look at the drawings) was the monitor and the coolant pump.

ammeter on the phase convertor, its a bought one 8hp, i just forget the breed at the moment
i believe there are 3 phases to the drive axis boards so single phase isn't possible
it does seem that if the power off sequence is not followed to the letter it will lunch the electronics

[Chaz]

ammeter on the phase convertor, its a bought one 8hp, i just forget the breed at the moment
i believe there are 3 phases to the drive axis boards so single phase isn't possible
it does seem that if the power off sequence is not followed to the letter it will lunch the electronics

Its worth checking. I had an original servo triac, it was all single phase powered.

[mark35gun]

ok not 100% on these by any means but i have definitely got 3 phases going to the axis boards
no coolant pump on it, as i don't use coolant really and no tool changer either as i like it without and for what i want i don't need one, just something else to go wrong

[Chaz]

ok not 100% on these by any means but i have definitely got 3 phases going to the axis boards
no coolant pump on it, as i don't use coolant really and no tool changer either as i like it without and for what i want i don't need one, just something else to go wrong

Some pics will be good. Some Triacs have wiring diagrams with them, do you have any you can scan / put here for review?

[mark35gun]

no i'm afraid not, no wiring diagram to speak of, but it is factory fanuc om, and un messed about with, i know that before i had the last meltdown i had low voltage alarms on x,y z, axis boards, i will try and post some pics later on today

[Chaz]

no i'm afraid not, no wiring diagram to speak of, but it is factory fanuc om, and un messed about with, i know that before i had the last meltdown i had low voltage alarms on x,y z, axis boards, i will try and post some pics later on today

Thanks. Ill do some quick googling but pictures will help.

[mark35gun]

odd thing is the guy i bought it off had ran it for 11 years with no problems with this set up,
now here's the thing, he disconnected the cabling from the phase convertor to facilitate moving the m/c and marked up all cables and where they go, i was very careful to re wire exactly as marked, but if he has made a mistake................

[Chaz]

odd thing is the guy i bought it off had ran it for 11 years with no problems with this set up,
now here's the thing, he disconnected the cabling from the phase convertor to facilitate moving the m/c and marked up all cables and where they go, i was very careful to re wire exactly as marked, but if he has made a mistake................

So I've had a quick look at every Denford wiring diagram I can see. I dont see anything where the actual servo drives are actually connected to all 3 phases, they seem to take a single phase for input power. That said, yours might be different.

[mark35gun]

you may well be right, i need to source boards before any testing can begin, although i don't know if i dare turn on the m/c!

[mark35gun]

25164
heres a pic not very good i know
BTW the phase convertor is a boost electrical engineering one rated at 8 hp, which i know is miles to big for the denford but it came with it25165

[Chaz]

25164
heres a pic not very good i know
BTW the phase convertor is a boost electrical engineering one rated at 8 hp, which i know is miles to big for the denford but it came with it25165

Very different looking to mine. Are you able to identify and take pics of the servo drives themselves? The wiring to them will be of interest, so too any model numbers to review how they get powered (based on a specsheet).

[mark35gun]

z axis no A06B-6058-H003
X,Y combined AO6B-6058-H221
i will post some pics in a short while

[m_c]

The reason I was asking about the phase converter, was they can produce voltage spikes, but if it has been working with the converter previously, it's not likely to a be problem. Just to be sure, it's probably worth measuring the voltages to make sure they are roughly similar.

Looking at the photo of the cabinet, it looks like the machine takes 3phase plus neutral (I'm assuming the blue wire between the main power switch, and main earth cable is a neutral..).
Again with the phase converter powered up, I would check the voltages. Check the 3 combinations of the phases, then each phase to neutral, then compare neutral to earth. Phase to phase should be similar, then phase to neutral should be similar, however the artificial phase (the one generated by the rotary) will likely be higher, but shouldn't be excessively higher.
On a normal 3P+N setup, neutral to earth should be near zero volts, however depending on the phase converter, it may be floating near normal single phase voltage.

[Chaz]

I looked up the drives, it looks like they take 3 phase (220V on the ones I saw) for the main power and a single phase feed for 'control voltage'.

[mark35gun]

no neutral on the m/c, the voltages across the 3 phases are 440,440,380, i am sure that the problem exists when the rotary phase converter is turned off without isolating the m/c first as it has done this twice now as soon as the motor shuts down the ammeter shows a current draw of +40 amps which lunches the control, normal running the ammeter shows 2-3 amps with the m/c on, i don't understand why there should be a large current draw when the phase converter is turned off and the m/c isolator is closed, i have no experience of rotary phase converters so i do not know if this behaviour is normal or not

[m_c]

no neutral on the m/c, the voltages across the 3 phases are 440,440,380, i am sure that the problem exists when the rotary phase converter is turned off without isolating the m/c first as it has done this twice now as soon as the motor shuts down the ammeter shows a current draw of +40 amps which lunches the control, normal running the ammeter shows 2-3 amps with the m/c on, i don't understand why there should be a large current draw when the phase converter is turned off and the m/c isolator is closed, i have no experience of rotary phase converters so i do not know if this behaviour is normal or not

Any chance you could take a photo of the inside of the phase converter?
When you say you switch of the phase converter, how do you switch it off?

My suspicion is switching off the phase converter doesn't actually isolates it's output, so it's still outputting 2 phases at full voltage, along with leaving the balancing capacitors active (aka acting like a static phase converter), which when combined with a switch mode load (aka the FANUC power module), could be resulting in some very high voltages on the false phase.

[mark35gun]

yes i will take some shortly, i think you are right, just stopping the phase converter with the stop start control Ie stop button, which is fine as long as you know to isolate before stopping.
i have always used vfd inverters where required but never rotary types, i was on the understanding that the rotary types were ok for non electronic machines, but too "coarse" for sensitive equipment, in saying that this m/c has run with this setup for many years so should it be considered ok?

[m_c]

Rotary converters are fine, however you just have to be aware of their limitations.
Some equipment won't tolerate a big mis-match on voltages, but even your mains 3 phase is rarely perfectly matched. You're only likely to get problems if the false leg is majorly out of tolerance, or you are pushing equipment to it's limit.

However some rotary converters leave a lot to be desired in terms of controlling the false leg, and safety protection.

[mark35gun]

pics of the phase converter, well part of it the other bit is the previous pic with the ammeter which is not so easy to get the lid off
you can see the stop button i use for off2516625167