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Hi Ed, Thank for your reply. Although I do not think it would be an issue, my question was to ensure there is no dissimilar metal galvanic corrosion concern. Any thoughts? Thanks

Hi, We have an instrument where one piece is Inconel alloy 625 in touch with the body of 316SS. It is in fact a rupture disk (thin plate) of Alloy 625) with a 316SS holder at both sides. I do not think there would be a dissimilar metal corrosion issue here however appreciate if you could...

Hi, We are considering use of an existing 60+ years plant. The main substation has both MV and LV gear in the same room, opposite each other. All the oil and air breakers, protection relay, etc. are still the original 1960's. There is an opportunity to upgrade if necessary. Is it a requirement...

Hello, Other than P&T compensation for dry gases, are "density meters" being used to make mass flow measurement by DP flow elements? (say an insertion type).This would be meaningful especially for large bore pipes where Coriolis. A thermal mass flow measurement is also heavily dependent on...

Hi Kiribanda, Having to use MV cable was my fear. Makes everything more difficult, from engineering, to procurement & installation and a whole lot of other head aches. Probably I need to face my fate!

Hi, I have an application where the supply is a "float" 700V rms, 50hz and the load is 50m away about 5kw, all at ambient temperature. Normal power cables are rated 0.6/1kv which seem to be ok (0.6kv core-earth and 1kv core-core), however my concern is if a fault occurs and one of the cores is...

Yes, I listen to more experienced guys sometimes!

Hi Keith & Scott, Here is a sketch I made for you: I did not sketch the full UPS side as it is a standard N+1 topology as I explained in my previous post. If we loose independent side e.g. a battery string, say faulty cell, or one inverter, etc. the other UPS will still provide the supply...

Thanks again to all of you who contributed to my query. Special thanks to Keith and Scotty. I ended up using an N+1 (in this case N=1) redundant UPS with one common bypass, two supply feeders, two rectifiers, two inverters, two battery banks each with their own cables and DC breakers with...

Thank you very much! I believe that is the most practical option now. I will put fully rated circuit breakers instead of fuses. Cheers

Keith, I do understand the potential issues and fully agree with the catastrophic failures you suggested. I have used modular chargers before (as Freddy has suggested), but in this case we have a UPS with single charger and single inverter. I am trying to figure out how to use diodes to fix the...

Using the diode will have the challenge of charging as we have a single charger only. We have two strings of 120V and the continuous current will be about 150A per string. (120*150*2*0.85=30KW with an assumed UPS efficiency of 0.85)

Great point Keith, Other than this, say on the day one, when we want to connect the two strings in parallel; if the two string have a slight voltage difference (which is very likely), there will be a considerable current from one to the other(uncontrolled as you mentioned). That would be also a...

Partially the price and the other is the UPS supplier didn't support this and also lacking other approvals we need in place for offshore use. The battery string voltage is 120v, single charger and we need both battery strings to have the desired autonomy time. I'm thinking if we lose one string...

@itsmoked @Scotty Thanks for your insight. We selected VRLA batteries. Now there is a second question. Is there a concern if we split the batteries into two parallel battery strings, each with it's own circuit breaker / isolator? Both will be connected with a common cable to the UPS. I'm...

Thanks Scotty and Freddy. @itsmoked Keith,thanks heaps for your concise and to the point reply. I really liked it. Cost is not much of a problem (Odd,I know!), and space is limited, so Watt per cubic inch matters. Site preference is to have single string of lower voltage, say 120vdc rather...

Hi, we are replacing an old 30KVAh UPS system for an offshore oil installation. We have been given options of: - Lithium Iron Phosphate (LiFePO4) Batteries; as well as - Valve Regulated Lead Acid Batteries - maintenance free (the same as existing ones) I am aware of the advantages of the...

Hi, Here is the application as follows: Existing orifice plate, 500mbar DP @ full scale gas flow of 900scfm (I know it is high DP!). I am going to use two DP transmitters in a split range arrangement. Which of these would you suggest? 1- Transmitter A: 0-50mbar (284scfm) Transmitter B...

Hi Roydm, A DP device is not a good option for a multiphase or wet flow or when the molecular weight of the gas is not constant and known. Cheers

Just to make it more clear, I am referring to model FLSE100-EXPR which is a single sided insertion probe holding both transceivers.