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ISO rating of Generators / engines

ISO rating of Generators / engines

ISO rating of Generators / engines

What is the meaning of ISO ratings in Generators / Engines?

RE: ISO rating of Generators / engines

Well, the document should say

The ISO rating standard for reciprocating internal combustion engines is ISO 3046; the standard for generating sets is ISO 8528

Both have several parts, 3046 is a core and satellite type standard: the corresponding definitions are in ISO 15550

RE: ISO rating of Generators / engines

Google ISO 8528 for Generator Set Ratings.


RE: ISO rating of Generators / engines

ISO ratings define power correction, transient response, power and application ratings, and multiple ISO standards can be referred to depending on which of these you're talking about.

So here is a nice presentation by Cummins discussing ISO 8528 Generator set reating,

and a more condensed version by CAT,

The article below is an overall draft specification, on page 7 is a very good reference list showing ISO and other industry specifications related to generating sets,

ISO 3046 typically deals with performance as it applies to fuel consumption, power output and correcting these to "standard" conditions.

EGSA also publishes several standards that apply to generating sets, which in many cases are inline with ISO and other industry and regulatory standards,

Hope that helps, MikeL.

RE: ISO rating of Generators / engines

I think for most "lay engineers", the issue is that, like all standards, they try to allow you compare apples to apples.

Hence the key line in that very useful set of definitions cat serv eng sent is one which says

"with the declared power adjusted or corrected as determined by the manufacturer to the standard
reference conditions specified in ISO 14396,"

In other words this is, I believe, 15C and 101.625 Kpa atmospheric pressure, i.e. sea level and cool air.

So then as this is not where most engines work, all mfrs then give de-rating charts or tables for the amount of power your ISO 1000kW engine can produce at the 1000m up in 45C of air temp ( probably about 800kW).

But it just gives everyone the same base condition with which to officially rate their engines & generators.

So when your non technical manager or finance person asks why are buying / using a 1250kW engine (ISO rating) for a 1000 kW actual duty you have the answer.

It's a bit like the manufacturers petrol (gas) consumption figures for cars. I don't know anyone that can get within 15% in real life, but to compare one vehicle to another they are a useful tool as they are also undertaken in ideal conditions. But you would never buy one actually expecting it to do what the mfr stated.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: ISO rating of Generators / engines

An old experience: About 35 years ago I was comparing fuel efficiencies for a customer who needed to purchase a prime power set for use in the Yukon Territory where fuel was very expensive.
Most engines had comparable fuel efficiency except for one engine that showed 10% less fuel consumption across several engine sizes.
I was prompted to look deeper and found the source of the discrepancy in some very fine print.
They were testing with fuel with a specific gravity 10% heavier than their competition.
When the fuel consumption was adjusted to account for the heavier fuel, their fuel consumption matched the other sets.
ISO standards avoid this sort of misleading information.

Ohm's law
Not just a good idea;
It's the LAW!

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