Generator or Backup Options?
Generator or Backup Options?
(OP)
I have what could be a quite basic question for you electrical guru's. I have some equipment that is in a rural area. During the storm seasons, intermittent power outages can occur. This causes the equipment to shut down, and must be manually turned back on.
My first thought was to get a generator to provide as a backup. But if I had some form of a battery backup, this may suffice since the outages are brief (a few seconds?). The power requirements are 45.6 amps.
What would guys recommend from your expertise?
My first thought was to get a generator to provide as a backup. But if I had some form of a battery backup, this may suffice since the outages are brief (a few seconds?). The power requirements are 45.6 amps.
What would guys recommend from your expertise?





RE: Generator or Backup Options?
ht
RE: Generator or Backup Options?
Maybe I can set something like this up in some sort of a meter house. Any additional thoughts?
I forgot to mention its 12 HP @ 45.6 amps, which includes surge for starting.
RE: Generator or Backup Options?
Can you give us details on this equipment?
What's the various equipment consist of?
What exactly does the poor schmuck who has to drive out there do when restarting the system?
Is this motor 3phase?
There could be some alternatives to the brute force method of a UPS.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Generator or Backup Options?
The equipment is an amine processing plant. There are 4 total electric motors:
1.) 5 HP - powers pump of fluid to amine tower
2.) 5 HP - powers fan (cooling of fluid return from re-boiler)
3.) 1 HP - booster motor pushes clean amine fluid back into surge tank (supply)
4.) 1 HP - powers reflux pump, condensate from steel column to reboiler.
RE: Generator or Backup Options?
Battery backup is going to be pretty expensive in terms of the load, just to get a short time of ride-through, and as you look for longer periods on the backup system, the battery bank size is going to be BIG.
old field guy
RE: Generator or Backup Options?
What is a PLC, and typically what size of generator would be required to provide the power requirements? Is there a good website or rule of thumb to go by?
RE: Generator or Backup Options?
Here is my point. If you can just pull the plug on your system and it fails/stops "safe" and an hour or a day won't hurt anything then you don't want the hassle of back up at all. You just need a way to restart things.
A generator is a theft target.
Now fuel is a target too.
It needs;
1) A thought out installation
2) regular testing
3) on site fuel storage
4) Permitting (sometimes)
5) it's own battery
6) regular servicing
7) Then you still need a way to restart things as the generator is not going to spring to life in less than a 1/4 second.
I suggest that if your system just needs a bunch of buttons pushed to restart everything than power-on timers set to start things in the normal sequence with appropriate delays would be the logical solution.
If however you need things to start in a certain order AND each thing must be working a certain way before you restart the next item (some do). Then you want to use a Smart Relay(cheap PLC) or a PLC to start things in the sequence desired and to check for conditions of interest before starting the next process.
DEF: PLC = Programmable Logic Controller.
It is a small computer system that is designed for industrial applications. It generally has a wider operating range than a PC and is somewhat hardened, and has industrial mounting, and field connections. They need programming to do what you want. Your application would probably be very easy to program.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Generator or Backup Options?
This is a natural gas compression site. We can utilize the natural gas to power any generators.
The amine facility removes H2S, CO2 and other contaminants from the gas stream. It is important to keep this running. The agressive storm season has brought a touch of inconsistency with the electric. I feel a backup is needed for sure in case electric may go down for X days. It seems to be sensitive to any fluctuations that may occur.
Perhaps a mix between the recommendations. A PLC + natural gas driven generator inside a protected building? A battery solution has seemingly been eliminated due to the power requirements and cost effectiveness.
The equipment is already installed and is inspected everyday. The on site fuel could be the natural gas.
RE: Generator or Backup Options?
I agree with itsmoked.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Generator or Backup Options?
RE: Generator or Backup Options?
OK Size..
waross; What are the numbers?
15~18kW?
You'll want to package up the smart relay and any required transfer switch controls, etc. Into a NEMA 4 enclosure. Etc.etc.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Generator or Backup Options?
I believe I've got a pretty good starting point now to evaluate the options available. If the thread remains open, I'll try to post back what the final setup turns out to be.
RE: Generator or Backup Options?
I would be wary of possible fast transfers.
The safest and simplest way is to delay the start of the restart cycle for 15 or 20 seconds.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Generator or Backup Options?
Im researching generators... It looks like some come with transfer switches, but they're manual type. Hopefully a portable size generator will work. I don't know if you can post links, but I found a Guardian 5396 Centurion 17,500 watt electric start portable generator that looks like it may work. Seems to be about as big as the portables get.
RE: Generator or Backup Options?
Any idea how often and how long power outages happen? Also, I was wondering about the comment you made about sensitivity -- do you run into problems with brownouts or voltage sags?
RE: Generator or Backup Options?
As far as sensitivity, if any lightning strikes occur in the area or anything, the system shut's down. The potential exists for a complete outage for a few hours. It's important for the system to stay running, so I don't want to assume power will just flicker and be back to normal. I want to plan for the worst and hope for the best. If power does go out for several hours, or longer I need to have the proper equipment in place.
RE: Generator or Backup Options?
Mains fails - 10 second delay starts swap over proceedure all kits requiring sequencing is dropped. The ACB incomer opens. Signal sent to generator this startsup and makes the generator phase relay happy. This times out and thens end a close signal to the generator incomer. The supply is not live to the board and your kit can go through a start up sequence. Do you need a hold off time so that if the mains came back on within say 5 minutes you would hold to generator or would you like to throw back over right away. Again think out the process for swapping back. Scheduled switch down of plant change over to utility and then sequence back up to normal operations again.
What you are talking about is quite a difficult process to think and apply some logic to - you need to eb 100% sure of your requirements and then make up a schedule of switching required and work from that. Think about how long you want to run on generators if you have switched over - put a delay in to stop say rapid back and forths if you dio have to go to generator - stops rapid drops in supply having your system fluctuate.
RE: Generator or Backup Options?
Recently I've been reviewing some replacement packages for backup generators here.
Most of them have control packages that take care of making sure that the generator doesn't "run for 5 minutes". If the generator doesn't have it, then many transfer switches have that feature in their controllers. One or the other will likely also include a periodic start and run of the generator so you can exercise it.
There are amazing capabilities in the new equipment, to the point that I sit here scratching my head wondering if we're getting a bit TOO complex for a simple generator backup scheme.
old field guy
RE: Generator or Backup Options?
I dont have a background with electrical details, so thats why I thought I would talk to you guys for your expertise on the subject.
Ideally, you would want to keep the setup as simple as possible. I did see where some generators have packages w/ transfer switches, but I didn't see any that were automatic.
I think the trick of complexity lies in the kW required for startup. I have 4 different motors, so I believe thats where a PLC may come into place, opposed to just having a backup generator w/ transfer switch.
ruggedscot is right, that this should be well planned out in regards to the timing. ruggedscot: You sort of lost me in your first paragraph.
RE: Generator or Backup Options?
ACBs? For a 45 amp load? You must have money to burn.
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If we learn from our mistakes I'm getting a great education!
RE: Generator or Backup Options?
The PLC can have the generator run the test load for 15 minutes a week so you dry out all the accumulated moisture from the engine oil etc.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Generator or Backup Options?
Anyone have any recommendations for type of PLC I would need? Would it be one like this: h
RE: Generator or Backup Options?
www.deepseaplc.com/
RE: Generator or Backup Options?
htt
Keith Cress
kcress - http://www.flaminsystems.com
RE: Generator or Backup Options?
Im trying to go over the generator requirements based on the data I have.
So if watts = (amps * volts) * load factor
Then, I would be at (45.6 * 240) * .8 = 8.755 kW
Is this correct? Would that for general operating? And I would need something in the range of 15-18 kW due to motor starting power demand? Can you guys educate me in this area?
RE: Generator or Backup Options?
As for your 45.6A that really means nothing in the context of how you've been using it. Have not a clue...
Is this three phase power or single phase power? Where did you get this number?
When it comes to motors, you are interested more in the HP than the current when sizing generators. You back into the current from the horsepower requirements.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Generator or Backup Options?
Joining the party late, but you need to define the problem and the goal first. The original post suggests "This causes the equipment to shut down, and must be manually turned back on."
Is the issue shut down of equipment or just manually starting back or both?
If just manual re-start is the problem, generator will not help as the equipment still will shut down and needs to be started up, either automatcially or manually.
If only a auto-start will solve the concern than all you need is auto restarting control circuit, which is pretty easy.
If even having momentary shutdown is an issue and you do not want to go down at all than you wil need a UPS. If the outages are longer than a few minutes than you may need both the UPS and generator. YOu need to define your issue further and apply the appropriate solution. Hire some experienced professional help.
RE: Generator or Backup Options?
Keith Cress
kcress - http://www.flaminsystems.com
RE: Generator or Backup Options?
In my last post I just wanted to see if I could calculate on my own how many watts would be required to operate the equipment to size the generator.
It's single phase electric. One of our operators gave me the 45.6 number. He may have totaled the # from the badge of each motor, I'll have to check back with him to see exactly.
Also FYI I will not be installing this myself. I'm just researching what options were available and I thought who better to ask than electrical engineers, no harm no foul :)
RE: Generator or Backup Options?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Generator or Backup Options?
RE: Generator or Backup Options?
RE: Generator or Backup Options?
18 kW to 24 kW is about the maximum size of single phase generators. Above that size three phase alternators are reconnected and re-rated for single phase.
You may be faced with sales proposals for both single phase machines and re-connected three phase machines.
For example, a three phase 30 KVA, 24 kW, 0.8 PF alternator will be reconnected as a single phase, 20 KVA, 20 kW, unity PF machine. The engine will still be capable of producing 24 kW. although the alternator will be overloaded.
A single phase 20 KVA machine will have an engine suitable for 16 kW or 20 kW depending on the power factor rating.
The re-connected three phase machine will start motors much better than the single phase machine. The short overload on the alternator during motor starting will not be an issue. The re-connected three phase machine will be well worth the extra money that it will probably cost. The engine will last much longer also.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Generator or Backup Options?
Keith Cress
kcress - http://www.flaminsystems.com
RE: Generator or Backup Options?
Since you have natural gas available a Hydrogen/Air fuel cell would be practical.
Regards
Roy
RE: Generator or Backup Options?
RE: Generator or Backup Options?