1.5 MW Cummins Diesel Genset
 

This is from a second hand used equipment dealer but shows the engine generator clearly.

These are what my customers use to keep up their data centers...this is actually a small one - most of my customers are using 2.0 or 2.5 MW units. The bigger ones look exactly the same except they’re larger, and 16 cylinder instead of 12.

You can hear the turbos (yes plural turbos) scream as he applies load...and a lovely cloud of black smoke to make Dieselmeken jealous.

This one has a burn rate of about 100 gal/hr under full load. The 2.0s about 125 gal/hr and the 2.5s about 150 gal/hr.

Note the 3 fuel filters on the left side of the engine. Yes the fuel is red because they are burning dyed diesel. There are 3 filters so that you can change one at a time while the engine is running. Same with the oil filters on the other side.

Behind the generator the big gray box is a load bank. It’s a giant toaster with a big fan in the bottom. This is how you load up the generator to test it. You can see they have temporarily cabled it up to the output breaker with cables. This is quite normal practice when commissioning the generator.

Normally these are either installed in a room in the building, or more commonly in a modular enclosure beside the building. In this case, the fuel tank sits underneath (so the generator is about 4 ft off the ground) and it has metal walls and a roof to protect it from the weather. The ends have lovers to draw combustion and cooling air in one end and expel hot air from the radiator out the other end.

https://youtu.be/wAKXxJ2ZWks

I design the power switchgear that accepts the power from these generators and sends it to the critical power loads. We have automatic switchover that chooses utility or generator power. Simple systems use one utility feed and one generator and toggle back and forth. More complex systems have multiple generators operating in parallel with each other for extra capacity and redundancy, and sometimes even parallel with the utility.

Another one, 2 MW Cat:
https://youtu.be/iLqlser0dL0

Nice. I appreciate this kind of diesel porn.

Interesting post. Never knew those large gen sets burnt so much fuel.

But when is Jay Leno going to show us a car with one of those engines? :cool:

-Rog

You forgot a u

The only thing cooler might be one of these:

https://www.youtube.com/watch?v=ZVHDYag61_0&t=116s

https://www.youtube.com/watch?v=HDXdpO9Vztw

Do a search on what Gale Banks has to say about smoke and power.

The smoke is only as the engine comes up to speed and then as the load is applied. For quick load response there will be over fueling as they slam a load to it. The exhaust on these gens in the vid isn't after treated as they are older.

_Emergency_ generators have a different standard due to their inherent limited use as compared to other stationary / off road / on road engines.

https://www.csemag.com/search/search-single-display/tiers-of-a-generator-emissions-regulations-for-diesel-gensets/5e1332076cea6d0e5c16845453bf50eb.html

Yes these are older machines without after treat.

Most of our customers take the 100 hr/year rule exemption and run for backup only. A few places require after treat regardless but many places do not. So even new ones roll the coal on 0-100% load.

A data center falls under NEC section 702, optional standby facilities, which is different than a hospital or other life safety related application (NEC 700 or 701 or NFPA 101, or JAHCO). So the 100 hour exemption does apply to a typical data center backing up internet related activities (like the data center holding the server(s) that hosts this forum).

Some data centers fall under critical operations facilities (like telephone exchanges, 911 centers, operations centers for electric utilities, etc) and they meet the emergency exception.

Remember the generator does not have a transmission like a car engine does. If it gets hit with a block load the only way to keep up is max fuel otherwise it will bog down and die, or the transient recovery will be very poor (to the point of equipment damage). Normally when this test is done for commissioning, there is a digital 'strip chart' recorder that is monitoring the voltage, current, and frequency, to determine how long it takes the engine to recover from a block load. The generator has to meet industry specifications to clear this type of event, only so many Hz below normal (usually cannot go below 55 Hz) and must recover in so many cycles (usually 30 or 1/2 second).

Fortunately most of our applications only see that 100% block load during their commissioning and maybe a validation test every several years. Due to the connected equipment design, the generator does not get hit with a block load when it is connected to the bus under normal circumstances. It sees much closer to zero load at breaker close with a gradual ramp (15-30 s) to full load.

When you have a utility outage, all input power to your equipment shuts off, until the generator gets started (usually within 10 seconds). The utility side circuit breaker opens, and then after the generator is ready, the generator side breaker is closed. When the generator breaker is closed, the equipment has gone to its power off condition.

Modern equipment in a data center consists of UPSs and cooling equipment. The UPSs have incoming stages that slowly (over the course of 15-30 seconds) ramp the input current from 0 to the actual demanded load. Same with the cooling equipment where all motors are on adjustable speed drives that ramp up similarly.

During this time, the UPS batteries have held up the computer load, and there is enough thermal inertia designed into the cooling system and the room environment, to survive the duration of the outage, until the cooling system can get started back up and running normally again.

So you in practice rarely see block loads from 0-100% like the guy in the videos is doing. But it is the most arduous test the generator has to face, so that is why the guy selling the generator shows it.

I totally get that the stationary equiment world is totally different than mobile and especially highway rated equipment (like our cars). I just wanted to share what really big diesel engines look like, a video of them running, and share something about what I do at work every day, which led me to own 4 diesel powered vehicles. The only gas powered things at my house are a lawn mower, pressure washer, and a baby sized 5 kW generator on a cart (which I take out every year, change the oil, and load bank with several space heaters...).

What... no response to your missing letter?

I want one...

I still kick myself for not buying a 6BT powered genset I saw on craigslist about 10 miles from me.

Older military unit I believe by the paintjob at least

Had been sitting for years, they had no idea if it worked, wiring was chopped up a bit, somewhere around 1500-2k hours on the clock.

I didn't have a trailer to move it. guy wanted $300...

Should have went and bought a trailer.
No clue what I would have done with it, but for $300, who could pass it up? me I guess.

Yep, I get what you are saying. I tend to a 800 KW CAT gen like the one in the vid.

My point to others was that smoke does not = power. Unfortunately in order to get a mechanical injected diesel up to speed quickly, it needs to be over fueled and will smoke. Once the gen is up to speed + load stabilizes, there isn't any smoke.

With electronically controlled injectors ( not just an electronic controlled fuel rack ) and sensors I'd suspect the smoke on load application will be much less.

Others had asked about slamming a load at cold start. A true backup generator has a block heater holding the engine coolant at about 130 * F so the cold start is more of a warm start.

Cool, what kind of facility do you manage, if you're allowed to say?

Mechanically engines definitely smoke a lot more on full load application than the common rail engines. Fortunately I haven't come across a mechanically injected engine in quite a while. Data centers always want the newest and best due to reliability reasons.

And you're correct about the engine being kept warm. Also the engines have a pre-lube pump that runs on intervals, to keep the oil film maintained on the bearing surfaces.

All this comes from the NFPA 101/NEC section 70x/JAHCO requirements that you are on the bus in less than 10 seconds. When you hit the start signal, it's pretty much clunk (starter solenoid), a second or 2 of crank, fire within the first revolution, full 1800/min about 3-4 seconds later, rpms stabilized, exciter enabled, and you are at 480 V and 60 Hz in about 6 seconds. That gives you enough time for your transfer equipment to get the generator on the bus and beat the 10 second clock.

Sorry, was that directed to me? I don't understand what you're asking.

Some data centers use rotating UPS's, rather than battery systems. These are high speed inertial flywheels that couple incoming power to yet another generator. A rotating UPS doesn't provide as much run time as a battery system, but it's significantly lighter. Otherwise battery weight would constrain the design of a large data center.

Just out of curiosity...how do you phase match the output of the generator in multiple generator installations or where the generator runs in parallel with utility power?

Heh...
In your original post, a funny misspell where you forgot the letter u in a word, kinda changing the intended meaning.

I am a thorough editor...