Problem- Real 3 phase vs 3phase rotary converter?

[bherr]

I'm running a Bridgeport Series II Interact 4 and have had this problem off and on over the past year. Sometimes I can't even get the ready lite and then sometimes it comes on and I can start the machine , but during a cycle run the machine spindle will shut down. this has the Contraves controller, which from what I understand will shut the spindle down if it see a fluctuation in the voltage for more than a few seconds. I have had the spindle DC motor rebuilt and have upgraded the phase converter from a 3 HP to a used 15HP which was with the machine. I also upgraded my electrical service to 200 amp and the machine has been running very good since doing that in march of this year. When I did the electrical upgrade the guy from the electric company stated that the power in my area was pretty bad and flucuate quite a bit.

Now my question: since about the end of May the machine started acting up again with the same problem. I can upgrade to real 3 phase power and this will cost close to $1000 or I can purchase a Temco 11 KW rotary phase converter for about $1050 + shipping. My spindle requir4es at least 8.8KW as it is a 7HP motor. Need options on the best way to proceed. Real or a good phase converter that will regulate the voltage.

Thanks,

Ben

[gus]

Obviously real 3 phase is the way to go. It really is short money for what you are getting. I don't know for sure, but I am willing to bet that you will be on a different circuit from the bad power in your area.

I am wondering if an isolation transformer is worth trying, it may slow down or damp voltage spikes.

[bherr]

Originally Posted by gus Obviously real 3 phase is the way to go. It really is short money for what you are getting. I don't know for sure, but I am willing to bet that you will be on a different circuit from the bad power in your area. I am wondering if an isolation transformer is worth trying, it may slow down or damp voltage spikes.

GUS,

I agree that real 3 phase would be better, but my concern is that the 3 legs coming in maybe just as bad as the single phase. With the Contraves spindle controller doing it's job and shutting down if and when it sees power fluctuations I may still have the same problem. I spoke with a guy at PhaseTec and he made the very same comment about the incoming power. PhaseTec states that they can control the voltage to +/- 1%, but then i read an article on the web were they did an evaluation of digital converters and they said they weren't very good. that's why I was trying to find someone on the forum that is using one.
Thanks for the come back.

Ben

[gus]

I cannot imagine that they can control the power better than what is coming in.

Actually, is there anyone around using 3 phase?

Maybe you could ask them how they fare.

[scadvice]

Check the leg your controller is running off of. Years back I used a Phase II generator and by bad luck had hooked the generated leg to the computer. It turned out that sometimes the machine would stop and shut down if I had the spindle on high range and moved the table in rapid (G00) at the same time.
What was happening was the generated legs voltage would drop so low (less than 90 volts) as to shut the computer down. I switched the phase generated leg off cpu and all was good again. The cpu runs off of a 5 volt transformer and it was a wrong voltage, wrong voltage out thing.
I would put in standard 3 phase before I would pay money for any other solution. Much better off in the long run. Steve

[bherr]

Originally Posted by scadvice Check the leg your controller is running off of. Years back I used a Phase II generator and by bad luck had hooked the generated leg to the computer. It turned out that sometimes the machine would stop and shut down if I had the spindle on high range and moved the table in rapid (G00) at the same time. What was happening was the generated legs voltage would drop so low (less than 90 volts) as to shut the computer down. I switched the phase generated leg off cpu and all was good again. The cpu runs off of a 5 volt transformer and it was a wrong voltage, wrong voltage out thing. I would put in standard 3 phase before I would pay money for any other solution. Much better off in the long run. Steve

Steve,
This BP has a Contraves controller for the spindle drive and then a Heidenhain 155b controller for the axis drives. I have spent many many hours troubleshooting this machine and have replaced or rebuilt things. the hardest thing is figuring out exactly were my problem is. One day the machine will run without a hitch all day and then the next day I have trouble getting the ready lite. Once I do get a ready lite and start the cycle run it may run to the end or shut down anywhere in the program cycle. the Contraves controller monitors the input voltages and will shut down the spindle motor if it sees a deviation of more than 2% for 30 milliseconds. I hate to thing I have to spend $2770 for a digital phase converter and then find out that's not my problem or convert to three phase power and that doesn't fix the problem either.

Ben

[scadvice]

interesting to note that the machine that caused me this same problem had a Heidenhain 151c controller on it. All I can say is that the problem turned out to be the generated leg off of the phase II being contected to the cpu transformer and its voltage drop during spindle and servo start. I flipped the lead to one of the regular power legs and the problem was gone. The voltage drop did not have any effect after that. Let us know how you solve the problem. Steve

[bherr]

Originally Posted by scadvice interesting to note that the machine that caused me this same problem had a Heidenhain 151c controller on it. All I can say is that the problem turned out to be the generated leg off of the phase II being contected to the cpu transformer and its voltage drop during spindle and servo start. I flipped the lead to one of the regular power legs and the problem was gone. The voltage drop did not have any effect after that. Let us know how you solve the problem. Steve

Steve,
I'm not sure I'm following you on the fix you did. When you refer to the phase II, exactly what are you referring to? This machine use to run without any problems until I purchased it and mover it to my location. I've got the L1, L2 and L3 legs coming off the 3 phase converter to the machine switch located on the machine as labeled. Can you explain in better detail?

Ben

[gus]

This has been brought up to you before.

The only things that run on 3 phase are ac motors [coolant pump] and perhaps your DC spindle. The AC spindles[in older machines] would run on 3 phase. The ENTIRE rest of the machine runs on two of the three phases. Those two phases NEED to be the 'real' power, never the 'fake' leg. This is not hard to figure out, but if you cannot, you will need to post an image of the wiring diagram, at least up to the power input up to the TNC since not many are familiar with this particular machine.

[scadvice]

As I understand the phase generators only one leg is artificially generated. We have for example L1 and L2 coming directly in as normal. Each of those 120v from your 220 v single phase coming ‘IN’. Coming out, you are getting the normal L1, L2, and a leg generated by the phase device, L3 (in this example). This particular generated leg is subject to the voltage dropping more severely then the ”natural” legs under the high loads of say the spindle starting in high range and or servos moving fast.
In my case, the leg that was artificially generated (L3) just so happened to be the leg that was wired to support the transformer (dropping the 120v down to the 5v) for the computer. With a heavy start up load on the spindle and or servo, L3 voltage would drop so much the transformer (120v in and 5 v out)… the 5 v would drop voltage severely enough to momentarily make the computer flicker and the machine would lose track of what it was doing and stop.
Anyone out there that can explain this better than me please speak up I not an electronic guy, I’m just repeating what I was told.
So…what I was told to do was… switch that L3 generated leg off of the computer and use one of the other legs to run it.
Your phase generator schematic may show which ”L” leg is generated mine did.