Physical Dimensions of a Diesel Generator

[jmbelectrical]

I'm working on a project that contains an indoor diesel generator installation whose space constraints are less than ideal, to put it lightly. Upon comparing generators from two different manufacturers with seemingly identical ratings and performance characteristics (Same kW/kVA ratings, same silencer type, same accessories, etc.), I was surprised to discover that one manufacturer's genset was drastically (4 feet shorter in length) smaller than the other. I have several questions:

1. What could account for such a difference in footprint?
2. Could the genset with the smaller foorprint imply that it's of an inferior design? (Maybe the components are "sandwiched" together, making it more difficult to service.)
3. Alternately, could the genset with the larger footprint necessarily imply that it's of an inferior design?
4. Would such a vast difference in footprints suggest that I made an error when retrieving the specification sheets? Maybe I'm looking at two entirely different gensets, each intended for a different application?

Any input is greatly appreciated.

 

[waross]

Why don't you show us the spec sheets. From the information that you have given us, we can make wild asset guesses. There are so many factors including the possibility of the wrong spec sheet.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[wayne440]

Depending on the size of the set, 4 feet may not be much. You mention space constraints, my guess is that ease of service will be affected more by that than by the design of the set itself.

 

[davidbeach]

I'd guess that one is the lower end of a block size and the other is at the upper end of a block size. If that's the case the bigger unit will likely last longer.

 

[ScottyUK]

On-skid fuel tank, presence or absence of a PMG, control panel location....?

 

[waross]

Speed, cylinder count, radiator mounting.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jmbelectrical]

Here is one manufacturer's specification sheet...

 

[jmbelectrical]

...and here is the other.

 

[waross]

Both sets are 12 Vee engines, with the same bore and similar displacements. Both sets run at 1800 RPM. The main factors influencing the overall length are, the length of the engine block, the space between the engine and the radiator, the thickness of the radiator, the length of the generator end, the size and placement of the terminal box on the back end of the alternator and the size and placement of the control panel.
For sets of that size the difference in length is not unreasonable.
Both Cat and Kohler have been building gen-sets for a long, long time and are quite good at it.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[FreddyNurk]

waross is correct, although both specification sheets supplied indicate that dimensions do not reflect the final product. This is often true as there are different factory options that can also change the configuration of the set, such as remote mounted radiators versus onskid, size and position of the control panel, whether an on set circuit breaker has been included and so on.

For standby applications there's probably not a lot of benefit in terms of attempting to remote mount radiators and play with pipework compared to what the manufacturer has worked out. For prime sets, this can make a difference (VSD driven electric fans for radiators as an example), although it can also make a detrimental difference to performance (good step load performance required but enormous air/air intercooler pipework due to remote radiator mounting).

If its a standby application, its probably just as easy to negotiate with a preferred supplier, although maintenance and support costs may come into it, depending on vendor. I've got no experience with Kohler, but I'd expect that either manufacturer is quite capable of changing some of the arrangement around to suit the location, CAT has been able to support previously for my applications (admittedly 50Hz though).

 

[racookpe1978]

Do NOT buy the diesel UNTIL you have shown the space constraints (length, width, height obviously) AND the specific room details with the vender: Access space< overhead access to lift parts and cylinders and rods ?), covers, ventilation, cooling air, cooling water, exhaust bends and twists, electrical cable bends, twist, mounts, cable clamps, and breakers), control box, sound AND heat insulation.

Length of rum times? Drains for fluids? Changing fluids, and access to change them!

 

[itsmoked]

rum times

Do not do this while spec'ing.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Big Prime power sets need quite a bit of space alongside. After approximately 15000 Hours they need an overhaul. Some have a very robust oilpan. There is a set of heavy duty hinges alomg one side between the block and the oil pan. The whole engine above the oilpan may be rolled over horizontally for access to the crank, con rods and bearings. With the engine basically laying on its side beside its normal position, you need working space around it and space to work on the adjacent engine.
Standby sets normally don't accumulate that many hours in their lifetime. By the time a typical standby set has accumulated enough hours to warrant an overhaul, so many years have gone by that it will probably be replaced with a new set.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[dicer]

Its a manufacture preference the foot print, and like mentioned contact both dealerships, and have them access the building and the install space. Both units are from good manufactures. The one you choose may be able to shorten or decrease the foot print to make it work. If you have such limited space its not going to be an off the shelf plug and play deal. It will need to be engineered to fit. Removing the skid and the radiator will shorten the genset as will removing any other additions included with the unit like fuel tank etc.