[moonman5]

Massive disaster today,

The thumping great big transformer (T2 bottom left hand side of cabinet) on my Bridgeport interact 1 Mk2 failed?

Started with a blown 20Amp fuse, every time I replaced it the fuse just blew, after lots of investigation with my meter I found the primary windings have failed in the transformer? why?.

looks bloody expensive, is there any way I can by-pass this transformer? run all the small stuff on single phase and use a vfd for the spindle motor?

Is it worth getting the transformer re-wound?

Help!!

[Al_The_Man]

What is the secondary voltage? if it is 240, run direct off of the mains supply.
What is it feeding?
Usually the transformer is the most rugged component in the system, it usually starts to tell you early on with overheat and fuses blowing.
Did you notice if it was running hot?
Al.

[moonman5]

Hi Al,

Thanks for your reply (be buying you another drink at this rate!).

The transformer was hot but I only noticed this after the event, that said it was making a louder humming noise than usual,

As per your question about straight from 240v mains, the T2 transformer has 3 taps in use,

The secondary voltages are:......

1 @ 380 volts feeding the three x-y-z servo drive boards (power supply to boards)

2 @ 180 volts feeding the L1/L2/L3 chokes also feeding the servo drive boards.

So is it still possible to run from 240 mains?

Allen.

[Al_The_Man]

I suspect you have a very heavy short circuit either on a Bridge rectifier or an internal short on the TXFMR?
If it is the Transformer I think it is, it is a 3ph in, and there is three separate single phase secondaries for each servo, It depends on what these secondary voltages are? I don't have a record of what they actually are?
It may be cheaper to obtain One large 240v 1ph TXFMR for all three rather than have the existing one rewound.
I just see three identical secondaries on the print I have?
Al.

[moonman5]

I suspect you have a very heavy short circuit either on a Bridge rectifier or an internal short on the TXFMR?
If it is the Transformer I think it is, it is a 3ph in, and there is three separate single phase secondaries for each servo, It depends on what these secondary voltages are? I don't have a record of what they actually are?
It may be cheaper to obtain One large 240v 1ph TXFMR for all three rather than have the existing one rewound.
I just see three identical secondaries on the print I have?
Al.

Hi Al,

You were right, there was a heavy short circuit in transformer,

I have been looking at the electrical diagram and this transformer (T2) supplies the drive boards/servo drives.

The taps from T2 are: 180v-0v-180v-380v

It looks like I could get away with just two transformers, and drive the spindle from Vfd, the bit that bothers me is (as you said) the voltages?

The schemetic shows a tap voltage of 380 volts from T2 supplying the three drive boards (3x L1 in)

It also shows a tap voltage of 180 volts to the three servo motors?

The servo motors i.d plates show a voltage of 145 volts @ 32 Pulse amps.

Any thoughts on transformers needed?

Allen.

[Al_The_Man]

Is there any way you can post a pic, as it appears different from what I have?
Power supplies for those motors would require ~90vac to 110vac source.
Depending on the drives, e.g. if they are 3 phase SCR drives then you would need a 3 phase source, but I doubt they are.
Do not use a VFD for AC source in any case.
Al.

[moonman5]

Hi Al,

Here are some pictures inside the electrical cabinet, T2 transformer is removed for testing at the moment, I have also included the schemetics supplied with machine,

I have noticed that the three servo drive boards have a 380 volt input on L1/L2.

Contraves Varydin is fitted to other cabinet

does this help?

Thanks Allen.

[Al_The_Man]

If you notice there is 180-0-180 1ph ACV fed to the drive, no DC supply indicated, and one side of the motor is returned to the 0v centre tap.
This would tell me they are more than likely SCR drives?
I don't have a clue why the 380 on L2?
If a schematic of the board was available it should explain all.
The rest is fairly simple, an enable and an analogue command.
Do you have a make/model number of the drives? if no schematic?
The transformer and drives you have is quite a bit different from the Texron model info I have.
I notice the drives are fed from an auto-transformer no isolation between primary and secondary?
Al.

[moonman5]

Hi Al,

Unfortunatly I do not have a schemetic of the servo drive boards I have attached pictures.

The Part/model number is:Z15-1A-240 (See pics)

Allen.

[Al_The_Man]

I don't understand why it would have cooked in the 1st place, it is fed off of two phases (1 PH) so by connecting 240 1ph direct to the 0 and 220v tap should have presented no problem? the auto transformer tap supplied the 380v.
I found the full schematic sheet on a web site.
I guess you are faced with a couple of possibilities, get the transformer rewound, probabally big $$.
Get a 240v to 180-0-180 transformer and put another with 200vac secondary in series with one leg of the other 180v secondary for the 380, the VA of the 200v TXFMR may not have to be high, the way to check to see where the 380 connection goes to, If it goes to semi-conductor Power devices, then the VA may be as high as the 180-0-180.
Al.

[gridley51]

The 380V on L1 and L2 feeds a transformer on the power supply part of the Bosch servo drive.
I can`t tell you the outputs of this transformer yet as I have a board where it is faulty an we are in the process of setting a good board up on the bench to measure these outputs.

[moonman5]

The 380V on L1 and L2 feeds a transformer on the power supply part of the Bosch servo drive.
I can`t tell you the outputs of this transformer yet as I have a board where it is faulty an we are in the process of setting a good board up on the bench to measure these outputs.

Hi gridley51,

Yes I have myself tracked these voltages back to the Bosch servo drive power supply boards (my Bosch boards are marked at L1/L2 380 Volts) It would be usefull to see what the output voltage is? kind of thinking it's gonna be 240 Volts! why the supply of 380v? odd?

Let me know what you find very interested and it will give me an idea on what transformer would suit, why is this transformer rated 3Kva? seems rather large just for three servos and drives?

Thanks for your input.

Allen.

[Al_The_Man]

I find it odd that they would jack the voltage up to 380 with an overwind and then transform it again?
If in fact L1 L2 go to the primary of a transformer internal to the drive?
Al.

[gridley51]

I find it odd that they would jack the voltage up to 380 with an overwind and then transform it again?
If in fact L1 L2 go to the primary of a transformer internal to the drive?
Al.

Would you like a picture?

[gridley51]

Hi gridley51,

Yes I have myself tracked these voltages back to the Bosch servo drive power supply boards (my Bosch boards are marked at L1/L2 380 Volts) It would be usefull to see what the output voltage is? kind of thinking it's gonna be 240 Volts! why the supply of 380v? odd?

Let me know what you find very interested and it will give me an idea on what transformer would suit, why is this transformer rated 3Kva? seems rather large just for three servos and drives?

Thanks for your input.

Allen.

Allen,I`ll let you know when we get round to doing it.Finding time is the problem.
I have found these drives very reliable and the one with the failed onboard transformer is the first one in years of running Interacts.
There are a few outputs from the onboard transformer.Like you I suspect 240v is one of them,there will also be plus and minus bias voltages and probably 18 v for rectifying to 24vdc.
Where in the UK are you?

[moonman5]

I find it odd that they would jack the voltage up to 380 with an overwind and then transform it again?
If in fact L1 L2 go to the primary of a transformer internal to the drive?
Al.

Exactly Al, why? The guy doing me a transformer asked exactly the same question? and as you have said the voltages are phase 1 anyway, so why put it thro another transformer to reduce the voltage yet again, I think this was a standard transformer with the machine being fitted with varying types of servo drives/boards that may have required the higher voltage perhaps?

[moonman5]

Allen,I`ll let you know when we get round to doing it.Finding time is the problem.
I have found these drives very reliable and the one with the failed onboard transformer is the first one in years of running Interacts.
There are a few outputs from the onboard transformer.Like you I suspect 240v is one of them,there will also be plus and minus bias voltages and probably 18 v for rectifying to 24vdc.
Where in the UK are you?

Hi gridley51,

Yes I have been told that these drives are normally very reliable, But i have (I hope) no problem with drives, just this great honking transformer!
I am in west sussex.

Allen.

[gridley51]

I think most of the British machines had the Bosch Z15 (13?) boards,maybe some with Contraves.
I think I saw someone writing somewhere that parts to repair these boards are unavailable and even Bosch won`t repair them.It would be an easy drive to replace though.
Big problems with these machines is the ERO encoders on the backend of the servo motors.
I`ve got a transformer out of one of these machines but it was a retrofit machine and was using an Indramat axis drive so I don`t know whether the trannie is original or not
Either way I`d need to keep it in case I wanted to use the Indramat somewhere else.
Thinking about it I have two Indramats and two trannies.

[gridley51]

I find it odd that they would jack the voltage up to 380 with an overwind and then transform it again?
If in fact L1 L2 go to the primary of a transformer internal to the drive?
Al.

Thinking about it,it`s not an overwind either.Input voltage to the primary is 415 volts in the UK,and the drive,like most things German would be made for a voltage of 380v between the mains phases.

[Al_The_Man]

Thinking about it,it`s not an overwind either.Input voltage to the primary is 415 volts in the UK,and the drive,like most things German would be made for a voltage of 380v between the mains phases.

True, I was looking at it from the 240v perspective?
But I am still thinking maybe the 180-0-180 is the motor power, one side of the the motor returns to the 0v point, indicating possibly SCR drive on the 180v?
And true these drives could easily be replaced by A-M-C if needed.
Al.