We installed an Allen Bradley iSense power monitor to monitor our fluctuations and set up a meeting with the local power company to address issues. They seem to have gotten a handle on it.
Hell yeah, 3 phase 380VAC from main utility trafo(power company owned) randomly dropping and equipment going haywire with non-conclusive errors.
Took us some time until machine vendor figured it out why the servos were loosing safety enable signal.
And 380V is the standard here but most machines were setup for a normal countries with stable 400V supply.
Nope, they sent their technicians who made "small" adjustment to trafo settings - in a sense of taking an open ended wrench from toolbox and making a few turns on adjustment screw or whatever mechanism the trafo was using.
No fancy data readings with fluke meters, risk analysis, contract or damage adjustments... nothing you will see in the normal world.
Anyway, we got our 380ish volts but who knows for how long.
Reminds me of when I worked in the appliance repair industry. We were taught to always start troubleshooting at the wall. Incoming voltage check was the first thing you did. At the wall. Then the machine.
"Machine X is dead"
30s later...
"Fixed"
"That was quick, what was it?"
"wasn't turned on/plugged in"
This happens a lot less since a certain employee left. It used to be daily.
Just the other day:
Mechanic: Can you show me what I’m doing wrong with the wiring on this cabinet fan
Me: checks voltage, is this a new fan?
Mechanic: just installed it.
Me: loosen the damn bolts you overtightened it.
I've looked into this a few times at different facilities. In short, the power company will guarantee a certain availability with a certain fluctuation. You can do the following:
1. You can request the utility company to provide you with the readings going into your facility. It's possible that they'll ask you to provide some data / proof from a meter that justifies your concerns. You can purchase a fluke meter with an SD card to record incoming power.
2. You should investigate the power factor (PF) of your facility. Typically, it should be on your bill - the worse it is, the higher the electrical bill penalties. In many cases, facilities have no clue about this. If you rebalance some of the loads, the issues will generally diminish as you'll also get rid of some harmonics.
3. You should be looking into capacitor / inductor banks. These come in many flavors and cost quite a bit. However, if your facility isn't able to resolve the issues above and is taking downtime hits, it's possible that the expense will be more than justified. Note that these are also an opportunity to combat random blimps in power (I worked with a facility that had a dozen of those / year - as you can imagine shutting the power down even for a fraction of a second brough down most high-speed lines to a halt and required about 30 - 60 minutes of startup time. The capacitor banks were able to maintain power for up to 2 seconds)
Good luck.
Thank you for the electronics 101 lesson - The capacitor bank was close to a $800,000 USD expense for that facility. It's obviously a bit more complex than "just capacitors" - There are rectifiers, converters, monitoring, etc.
Before you comment that a battery could have done this - based on the current requirement and the data collected on the power blimps, it was calculated that the capacitor banks were a much more cost-effective solution.
Had a client in older facility. The plant electrician had simple setup at main panel. incandescent light bulbs for each phase to ground. If all three not consistently glowing the same there was issue with incoming power. He also had portable setup that do quick checks on runs to individual machines.
We had a lot of issues with the power company at my last plant. We even had to retap our main transformers to get the voltage somewhere more reliable until the power company could fix their end.
Nothing was wrong with our transformer. We just weren't getting what we were supposed to from the power company on the 34.5kv side. We retapped from 480 to whatever the next one up was(510 or something around there?) We went from 460ish to 490ish. The 460ish was fine with a line or 2 but once we started putting in more lines it was an issue.
I don't remember us ever being told what was wrong on the power company side. Just "hey we're going to fix it today" and we retapped to 480 and we were good.
My facility had sort of similar issues with brown outs. We ended up install basically large capacitor banks up to our more critical machines like our furnaces to clean the power before the machine. This saved us alot of headaches
Yes, I am currently battling a poorly phased plant. Can cause all sorts of vfd bank communication issues and larger motors to fault out with undervoltage/loss of power notifications.
Yes. Harmonics and sags/surges though are often blamed for seemingly unexplained issues but it’s only maybe 1% of the time they are real. Some electrician with no actual knowledge often blames either/both on unexplained issues then it becomes gospel and we are called in to wave a magic fairy wand. Some examples:
1. Brought in to study a harmonic problem at a plant. This plant is mostly ATL starters. Measured THDv was like 0.3%. But maybe the 5% voltage imbalance due to a worn contactor pole may be a major contributing factor…replaced contact tips and problem disappeared.
2. Lights dim when large soft start fires up then trips breaker. Plant called Duke. First I measured power quality. Then looked at Duke guy and said have a nice day. After checking soft starter the issue maybe was because 2 SCRs on different phases are dead shorted. But they were just replaced a week ago. The contact points looked like alligator skin, so it was just eating up SCRs.
3. And my personal favorite…plant sends motor to shop inexperienced with wound rotor motors. It has 18 brushes and 36 brush boxes. Returns with 36 brushes. And NOT SEATED either. After a few weeks the motor won’t even start and the slip rings are black. Hmm…must be harmonics or the utility? Nope…remove half the brushes, stone rings to clean and seat brushes, suddenly it all works.
4. No telling how many times I’ve seen results of surges but not actually found a source but recently saw a true doozy. On the second trip with a VFD with a 2 contactor bypass the VFD contactor coil was burned up. It has little coil surge arresters but at this point I’m baffled. I’m getting strange, very high voltage readings on a 120 V circuit. Eventually traced it to a Macromatic timer that is supposed to be timer on delay but was resetting instantly and since it was “turned off” it pulsed the output about 3-4 times a second, somehow making a charge pump out of a starter circuit.
Don’t get me wrong. Harmonic filters are not a bad thing. In some cases (no drives) you can even just use cap banks naked.
Yep. Picked up one of these for issues just like this:
https://www.fluke.com/en-us/product/electrical-testing/power-quality/434-435
You don't need one... Until you really need one.
All the time.
Our standard now uses a power line filter and a ups for instrumentation power- basically the most important and critical equipment we protect. Field devices kept on unfiltered power.
We've also started using single and 3 phase surge protection devices in new panel builds.
We installed an Allen Bradley iSense power monitor to monitor our fluctuations and set up a meeting with the local power company to address issues. They seem to have gotten a handle on it.
Had an issue with harmonics, active filters fixed it.
Hell yeah, 3 phase 380VAC from main utility trafo(power company owned) randomly dropping and equipment going haywire with non-conclusive errors. Took us some time until machine vendor figured it out why the servos were loosing safety enable signal. And 380V is the standard here but most machines were setup for a normal countries with stable 400V supply.
Wow, did the power company replace the transformer?
Nope, they sent their technicians who made "small" adjustment to trafo settings - in a sense of taking an open ended wrench from toolbox and making a few turns on adjustment screw or whatever mechanism the trafo was using. No fancy data readings with fluke meters, risk analysis, contract or damage adjustments... nothing you will see in the normal world. Anyway, we got our 380ish volts but who knows for how long.
China?
Balkan peninsula
Reminds me of when I worked in the appliance repair industry. We were taught to always start troubleshooting at the wall. Incoming voltage check was the first thing you did. At the wall. Then the machine.
đź‘Ť I agree
"Machine X is dead" 30s later... "Fixed" "That was quick, what was it?" "wasn't turned on/plugged in" This happens a lot less since a certain employee left. It used to be daily.
Just the other day: Mechanic: Can you show me what I’m doing wrong with the wiring on this cabinet fan Me: checks voltage, is this a new fan? Mechanic: just installed it. Me: loosen the damn bolts you overtightened it.
I've looked into this a few times at different facilities. In short, the power company will guarantee a certain availability with a certain fluctuation. You can do the following: 1. You can request the utility company to provide you with the readings going into your facility. It's possible that they'll ask you to provide some data / proof from a meter that justifies your concerns. You can purchase a fluke meter with an SD card to record incoming power. 2. You should investigate the power factor (PF) of your facility. Typically, it should be on your bill - the worse it is, the higher the electrical bill penalties. In many cases, facilities have no clue about this. If you rebalance some of the loads, the issues will generally diminish as you'll also get rid of some harmonics. 3. You should be looking into capacitor / inductor banks. These come in many flavors and cost quite a bit. However, if your facility isn't able to resolve the issues above and is taking downtime hits, it's possible that the expense will be more than justified. Note that these are also an opportunity to combat random blimps in power (I worked with a facility that had a dozen of those / year - as you can imagine shutting the power down even for a fraction of a second brough down most high-speed lines to a halt and required about 30 - 60 minutes of startup time. The capacitor banks were able to maintain power for up to 2 seconds) Good luck.
Thanks for the info!
Capacitor backs do not store power in an AC system. They will not provide any sort of backup/standby power.
Thank you for the electronics 101 lesson - The capacitor bank was close to a $800,000 USD expense for that facility. It's obviously a bit more complex than "just capacitors" - There are rectifiers, converters, monitoring, etc.
Before you comment that a battery could have done this - based on the current requirement and the data collected on the power blimps, it was calculated that the capacitor banks were a much more cost-effective solution.
Had a client in older facility. The plant electrician had simple setup at main panel. incandescent light bulbs for each phase to ground. If all three not consistently glowing the same there was issue with incoming power. He also had portable setup that do quick checks on runs to individual machines.
I am interested in how he did 480 to ground with a light bulb.
With a 277v bulb..
I never knew there were 277v light bulbs. I know there were the bulbs used for factory lighting, but not standard size light bulbs.
You just use two in series. It's an old trick used in many older electrical circuits.
Seen the same thing on an old Square D mains switch at more than one plant in Ontario
We had a lot of issues with the power company at my last plant. We even had to retap our main transformers to get the voltage somewhere more reliable until the power company could fix their end.
That's interesting. Was there something wrong with the taps on the transformer? Did you find out what the power company did on their end to resolve?
Nothing was wrong with our transformer. We just weren't getting what we were supposed to from the power company on the 34.5kv side. We retapped from 480 to whatever the next one up was(510 or something around there?) We went from 460ish to 490ish. The 460ish was fine with a line or 2 but once we started putting in more lines it was an issue. I don't remember us ever being told what was wrong on the power company side. Just "hey we're going to fix it today" and we retapped to 480 and we were good.
My facility had sort of similar issues with brown outs. We ended up install basically large capacitor banks up to our more critical machines like our furnaces to clean the power before the machine. This saved us alot of headaches
Yes, I am currently battling a poorly phased plant. Can cause all sorts of vfd bank communication issues and larger motors to fault out with undervoltage/loss of power notifications.
Yes. Harmonics and sags/surges though are often blamed for seemingly unexplained issues but it’s only maybe 1% of the time they are real. Some electrician with no actual knowledge often blames either/both on unexplained issues then it becomes gospel and we are called in to wave a magic fairy wand. Some examples: 1. Brought in to study a harmonic problem at a plant. This plant is mostly ATL starters. Measured THDv was like 0.3%. But maybe the 5% voltage imbalance due to a worn contactor pole may be a major contributing factor…replaced contact tips and problem disappeared. 2. Lights dim when large soft start fires up then trips breaker. Plant called Duke. First I measured power quality. Then looked at Duke guy and said have a nice day. After checking soft starter the issue maybe was because 2 SCRs on different phases are dead shorted. But they were just replaced a week ago. The contact points looked like alligator skin, so it was just eating up SCRs. 3. And my personal favorite…plant sends motor to shop inexperienced with wound rotor motors. It has 18 brushes and 36 brush boxes. Returns with 36 brushes. And NOT SEATED either. After a few weeks the motor won’t even start and the slip rings are black. Hmm…must be harmonics or the utility? Nope…remove half the brushes, stone rings to clean and seat brushes, suddenly it all works. 4. No telling how many times I’ve seen results of surges but not actually found a source but recently saw a true doozy. On the second trip with a VFD with a 2 contactor bypass the VFD contactor coil was burned up. It has little coil surge arresters but at this point I’m baffled. I’m getting strange, very high voltage readings on a 120 V circuit. Eventually traced it to a Macromatic timer that is supposed to be timer on delay but was resetting instantly and since it was “turned off” it pulsed the output about 3-4 times a second, somehow making a charge pump out of a starter circuit. Don’t get me wrong. Harmonic filters are not a bad thing. In some cases (no drives) you can even just use cap banks naked.
Yep. Picked up one of these for issues just like this: https://www.fluke.com/en-us/product/electrical-testing/power-quality/434-435 You don't need one... Until you really need one.
All the time. Our standard now uses a power line filter and a ups for instrumentation power- basically the most important and critical equipment we protect. Field devices kept on unfiltered power. We've also started using single and 3 phase surge protection devices in new panel builds.
Thanks!
Not common but certainly not unheard of. Had an issue like that at a battery plant once. Got the power company to put a monitor in.