3 phase chain motors

[JD]

"getting faults on all their gear"
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Somebody should investigate this as all future shows at this venue will probably have problems. Since Delta ignores the neutral, it probably isn't another case of that dreadful "Triplen Harmonic Filter in transformer" thing. Faults on protectors? Power disruptions like that usually involve a questionable connection. Bad connection = heat = risk of fire.

 

[David Ashton]

have you tried swapping 2 of the phases, it could be that the controllers will only work with the correct phase rotation and swapping 2 phases will make it work.

 

[epimetheus]

have you tried swapping 2 of the phases, it could be that the controllers will only work with the correct phase rotation and swapping 2 phases will make it work.

This. Phase rotation can be critical to 3 phase motors. If it's backwards, up could be down and down could be up, depending on the type of motor.

 

[danTt]

This. Phase rotation can be critical to 3 phase motors. If it's backwards, up could be down and down could be up, depending on the type of motor.

Yes, but up being down, and down being up, is not the same as up being nothing and down being nothing. The potential between phases should be the same regardless of how they are rotated..

 

[epimetheus]

Yes, but up being down, and down being up, is not the same as up being nothing and down being nothing. The potential between phases should be the same regardless of how they are rotated..

True, but if the motor controller has a phase rotation relay to protect against possible reverse rotation, it would explain why the motor controller wouldn't work even if the 3 phase-phase voltages have the same magnitude. I doubt many theatrical electricians carry a phase rotation meter.

 

[JD]

True, but if the motor controller has a phase rotation relay to protect against possible reverse rotation, it would explain why the motor controller wouldn't work even if the 3 phase-phase voltages have the same magnitude. I doubt many theatrical electricians carry a phase rotation meter.

But.....

However the video group is using bldg power and getting faults on all their gear and power protectors

I keep seeing that line and thinking, now a second crew with a totally different load application is having problems. This sounds like something other than basic phase rotation.

 

[David Ashton]

check the phase rotation, the faults with the video crew could be totally unrelated, it is always a trap to assume the faults are related, it could be pure coincidence, the number of times I've been fooled by coincidences.The first rule of fault finding is never assume anything.

 

[newdaypro]

But.....

I keep seeing that line and thinking, now a second crew with a totally different load application is having problems. This sounds like something other than basic phase rotation.

John,
We're still scratching our heads on the three phase issue. Got got plenty of road time for that.

However, our crew is more concerned about the 130 volts, as our sound and lighting would be running off that voltage. Is this an issue with source four pars, LEDs, and moving lights? Also, would this be an issue with jbl vertecs?

 

[Lsly]

John,
We're still scratching our heads on the three phase issue. Got got plenty of road time for that.

However, our crew is more concerned about the 130 volts, as our sound and lighting would be running off that voltage. Is this an issue with source four pars, LEDs, and moving lights? Also, would this be an issue with jbl vertecs?

130v while high, its not that high. Did anyone open the service and confirm a 3phase 5 wire set? Or did they just drop you five CAMs?

LS

 

[newdaypro]

130v while high, its not that high. Did anyone open the service and confirm a 3phase 5 wire set? Or did they just drop you five CAMs?

LS

We were only able to meter at the disconnect. Even though there were 5 wires I cannot confirm where those five came from. I do know it was 130v per leg and 225 across r-b, r-blue, b-blue.

 

[newdaypro]

Is

We were only able to meter at the disconnect. Even though there were 5 wires I cannot confirm where those five came from. I do know it was 130v per leg and 225 across r-b, r-blue, b-blue.

Is there something I should have been looking for as far as the ground is concerned? Whether it's just tied into a pipe, as in an older facility, or run back to the transformer feeding the building?

 

[porkchop]

Is

Is there something I should have been looking for as far as the ground is concerned? Whether it's just tied into a pipe, as in an older facility, or run back to the transformer feeding the building?

Your ground and neutral should be bonded (easy test is to see if you have continuity between the ground and neutral cams coming out of the house disconnect). If that's not the case it could have something to do with your video problem, but every Skjonberg motor distro I've ever worked with only used 3 phases + ground so it wouldn't explain your motor issue.

If you're strictly using this service for 3 phase + ground (a.k.a. only for motors) for testing purposes only you could try connecting the system ground to the house neutral and test the system in that configuration. I've worked in buildings where a dodgy ground has caused issues and this worked (All of them where out of the US and didn't have a bonded neutral and ground though).

I do not mean to insult your abilities or those of your crew and I'm not there to even say if this is really applicable, but I would say you should look at the possibility of it being a phantom issue. I've seen a lot of really good techs fighting to make something work take it apart and put it back together the same way and have it work perfectly afterwards. Is it possible that you had some kind of issue between the power source and the motor control system that could have been missed during initial trouble shooting with building power but was "fixed" in the process of disconnecting from building power and tying into the genny?

SIDE NOTES:
I've had to use a water pipe for a ground in the past. It's not ideal, but in some buildings/locations it's the most effective option. Try driving a ground spike in metro LA and you'll be lucky if the building electrician knocks you out before the underground utilities do.

If you find that the ground and neutral aren't bonded you can use some cam T's to bond them. One way is to put a T inline on both the ground and neutral lines between the house disconnect and your power disto. Then if you connect the 2 T's together your ground and neutral will be bonded. Ideally this should happen as close to the source as possible. It's not pretty, but it works.

 

[newdaypro]

Your ground and neutral should be bonded (easy test is to see if you have continuity between the ground and neutral cams coming out of the house disconnect). If that's not the case it could have something to do with your video problem, but every Skjonberg motor distro I've ever worked with only used 3 phases + ground so it wouldn't explain your motor issue.

If you're strictly using this service for 3 phase + ground (a.k.a. only for motors) for testing purposes only you could try connecting the system ground to the house neutral and test the system in that configuration. I've worked in buildings where a dodgy ground has caused issues and this worked (All of them where out of the US and didn't have a bonded neutral and ground though).

I do not mean to insult your abilities or those of your crew and I'm not there to even say if this is really applicable, but I would say you should look at the possibility of it being a phantom issue. I've seen a lot of really good techs fighting to make something work take it apart and put it back together the same way and have it work perfectly afterwards. Is it possible that you had some kind of issue between the power source and the motor control system that could have been missed during initial trouble shooting with building power but was "fixed" in the process of disconnecting from building power and tying into the genny?

SIDE NOTES:
I've had to use a water pipe for a ground in the past. It's not ideal, but in some buildings/locations it's the most effective option. Try driving a ground spike in metro LA and you'll be lucky if the building electrician knocks you out before the underground utilities do.

If you find that the ground and neutral aren't bonded you can use some cam T's to bond them. One way is to put a T inline on both the ground and neutral lines between the house disconnect and your power disto. Then if you connect the 2 T's together your ground and neutral will be bonded. Ideally this should happen as close to the source as possible. It's not pretty, but it works.

Thanks for the info. First, let it be known to all that I'm too old and too tired to be offended or insulted by anything or anyone. I'm trying to get through this as we're scheduled back in the same facility next year. That being said, in answer to your questions......
We took the controller to the disconnect, bypassing all of our gear, feeder and their feeder. Still no good.
And, as someone suggested earlier, we will will be carrying a phase rotation tester with us.
Finally, we did not check the bonding between neutral and ground.

All the info you and others gave us has been a tremendous help. The three phase issue may have been a quirk. Once you think you've seen it all, you get kicked again.

However, we've never had power that high and are still wondering if that could be an issue with our sound and lights. We're still on the road (it's a 7 week tour) and everything has been fine since then. No where near 130 in any other facility.

 

[porkchop]

When given the option I used to tap the transformer at between 125V and 130V (usually shot for 128V) phase to ground to help with voltage drop and it never made any of our gear angry (Clay Paky fixtures, Martin Servers and lighting consoles, Barco projectors, and Meyer Audio gear).

 

[BillConnerFASTC]

As I posted above, when company switches were primarily for dimmers we recommended tapping up the output 4 taps or usually 10% - 132 volts - and then trim the fixed dimmers to 120 volts at the socket. The 115 volt lamp largely changed that, not to mention a bunch of other changes. Separate company switches for lighting (rolling racks), motors, and sound (on isolation transformer) was the recommendation.

 

[JD]

At times of low load (spring and fall) voltages often are high. About 2 months ago, I came into work and found most of our lights ghosting. Since they were LED, it was quite noticeable. Analog dimmers (house lights in the sanctuary) so I went to the rack and my hots were all above 130. Trimmed the offending dimmers down a bit and end of problem. I would suspect if the controller was upset about voltage, we would hear of a lot more problems.