What can you do if you don't have generator alternator data
- Thread starter binwork91
- Start date
Birken Vogt
Senior Member
- Location
- Grass Valley, Ca
What do you know about the generator?
KVA, KW, Voltage. What other information is important to consider?
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
What type of study are you having done?
For short circuits, the normal source utility fault contribution is usually greater than that from any single generator.
For arc flash studies the generator data is often critical. Experienced engineering firms may have enough historical data that they are able to make some assumptions, kind of like estimating a transformer impedance.
For short circuits, the normal source utility fault contribution is usually greater than that from any single generator.
For arc flash studies the generator data is often critical. Experienced engineering firms may have enough historical data that they are able to make some assumptions, kind of like estimating a transformer impedance.
Is there a better method? I’m uncomfortable estimating values based only on experience.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
When I have the manufacturer, model number and serial number from the nameplate, but not the x"d, I contact the vendor rep to get the x"d for the alternator.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
I always say, if you are going to guess at the input data, just skip the work and guess at the results also.
However you can also perform multiple studies, using different realistic data, such as from IEEE books, and then try to determine a worst case result.
But I am guessing you want to know if you can make some type of field measurements in order to get the data you are missing.
What size is your generator and what type of study are you performing?
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
There has to be a name plate on it. Probably all kinds of data plates on components inside. I take it you're not on site?
For the project I am working on, it is 200KW generator, and it is arc flash study.
But when a project need both short circuit and arc flash, it is a headache.
Some generator does not have alternator nameplate.
I think Ron’s idea is good. I can try using the model number and serial number to contact the manufacturer.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
For short circuit, the normal source values will be higher. For arc flash the generator incident energy will be higher, as it is common for small generator fault currents to be below the instantaneous pick up point of OCPDs.
I have never seen the x"d any place other than the generator data sheets, which were often only available from tech support.