120VAC Control Power Conditioner
120VAC Control Power Conditioner
(OP)
I have run into a difficult situation at a site. The power is experiencing 30% to 80% THDv with a corresponding 25% voltage rise. The worst harmonics are the 59th and the 61st, with lower levels of 53rd, 55th, 65th and 67th. See the attached files showing this distortion. Anyone have a suggestion for a product that would filter this to clean up the 120VAC control power?





RE: 120VAC Control Power Conditioner
If the load is not too heavy, an Uninterruptible Power Supply (UPS) may be the best because it creates its own AC output.
Otherwise, there are large power line conditioners available.
Google:
"Uninterruptible Power Supply"
"power line conditioners"
RE: 120VAC Control Power Conditioner
There are a few solutions, but which might work will depend on what size the load is.
RE: 120VAC Control Power Conditioner
RE: 120VAC Control Power Conditioner
http://www.synqor.com/mpc/
I also ran across these units on some diesel electric Coast Guard ice breakers after we had identified power supply issues for our controls, this is what the Coast Guard/shipyard sourced and they appeared to take care of the problems
http://www.clary.com/products/military-ups/cmn-ser...
Mike L.
RE: 120VAC Control Power Conditioner
The down side will be the heat, plus the fact that ferros clip current peaks, so they have to be seriously over sized if supplying non-linear loads (which is just about everything now). You may need a 1kVA unit or maybe even 1.5 kVA depending on the nature of your loads and experience quite a heat gain if it is inside of a control cabinet. I would go for a hard-wired version and mount it on the outside if at all possible.
"Will work for (the memory of) salami"
RE: 120VAC Control Power Conditioner
RE: 120VAC Control Power Conditioner
RE: 120VAC Control Power Conditioner
Years ago I was did some work for Boeing Computer Services putting together an inventory management system at the assembly floor based on networked 80286 IBM PCs ("Gearboxes" if anyone remembers those behemoths). At that time the concept of "harmonics" in AC power lines caused by non-linear loads was still relatively new. BCS, being a very early adopter of PCs in mass quantities, began having problems with neutral conductors inside of walls actually starting fires. We put MCS units in front of every PC on our project in the Renton facility, the problems all went away. Like I said though, the ferros don't like high peak current gulps, they clip them, so the units had to be over sized. We ended up having to put 1kVA units on PCs with 500W power supplies.
"Will work for (the memory of) salami"
RE: 120VAC Control Power Conditioner
It sounds almost contradictory, but for this case, don't try to over-design something "perfect" because the ideal solution might always be "one problem away" or "one budget too expensive" or "one more part needs to be optimized" (or designed) to make the "best black box" from getting solved. For example, the Army had a problem with its boots in the desert. So, to solve it, they used the original "bad boots" in the desert for 15 years (and still are using them) while the Army/government/research labs/universities/bureaucracies tried to get new boots. They were on the shelf the whole time fro commercial fabricators. The new boots have at last been designed, but are not yet fabricated. None have been issued. "Testing" is still underway. )
RE: 120VAC Control Power Conditioner
RE: 120VAC Control Power Conditioner
Motor Generator ?
RE: 120VAC Control Power Conditioner
RE: 120VAC Control Power Conditioner
RE: 120VAC Control Power Conditioner
It looks like there could be a few noisy switch mode power supplies on the line. If upgrading them to something less noisy is not feasible, could they each be supplied with a local source of harmonic current like an appropriately sized capacitor? I suggest this it seems the THDv is particular high when the network is unloaded, so I suppose its mostly due to inductive voltage drop from the high frequency current draw of the non-linear loads. The actual current draw could be quite small, so a few well placed capacitors could work out to be a much smaller investment than a network-level power conditioner.
RE: 120VAC Control Power Conditioner
RE: 120VAC Control Power Conditioner
RE: 120VAC Control Power Conditioner
RE: 120VAC Control Power Conditioner