About the point I made in #7.
But if you still have doubts, open a thread regarding universal applicability of any of the rules of NEC, if you really care.
Required Load Bank
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About the point I made in #7.
But if you still have doubts, open a thread regarding universal applicability of any of the rules of NEC, if you really care.
Please state the significance of 0.8 pf on the name plate of an alternator.
We build for and supply into Saudi Arabia. Do you?
In means 0.8 pf.
Why is it 0.8pf, not 0.9 or unity pf? or Why is it mentioned at all?
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No?
Then you are hardly in a position to lecture me about what standards are applicable there, are you?
Maybe the 50Hz from the OP could have have clued you in.
And, for the avoidance of doubt, the recent project for Saudi Arabia, like many before, specifies the following:
This is taken, verbatim, from the contract documents. For an actual contract going through our works right now.
You will of course, with your encyclopedic knowledge of all matters electrical, know that those required standards are IEC.
Is that a test question?
There are commonalities between all standards and NEC places no frequency restriction on its applicability as far as I know.
Now why not try my suggestion of opening a thread on the universal applicability of any NEC rules?
An enlightenment question.
Do you need enlightenment?An enlightenment question.
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Going back to testing the generator at .8 PF:
It is true, for the most part, that you could test the generator windings, etc. with a resistive load of 1.25 times the rated kW (corresponding to the current at rated KVA at .8 PF.) But I would be concerned that the prime mover could not support that, hence the need for a reactive load to set up the high current test.
It is true, for the most part, that you could test the generator windings, etc. with a resistive load of 1.25 times the rated kW (corresponding to the current at rated KVA at .8 PF.) But I would be concerned that the prime mover could not support that, hence the need for a reactive load to set up the high current test.
iceworm
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An enlightenment question.
Any chance you two could take this outside so we could maybe hear from the OP again?
Gold - thank you
ice
iceworm
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I've been involved with several FATs and it's rare that anything other than a resistive bank is used. In fact, the bigger the gen, the less likely the load bank will be anything other than resistive.
It's true that the alternator can not be run at FLA with a resistive bank, However, the usual weak link is the driver and one can test that to the spec with a resistive bank.
The only other method I have seen used is to run the test gen in parallel with another gen (~ equal sized), both driving into a resistive load bank. Then one can overdrive the test gen field and set it to put out vars. The paralleled gen will drop back on it's field and suck vars. This is a lot of machinery, but generally better than getting a reactive bank.
ice
Gold,
I guess the OP is concerned with the required regular test run of DEG per AHJ. Correct me if I'm wrong but, they're making sure equipment and procedures are in-place so problems like wet stacking are avoided. That said, it is the prime mover that needs to be exercised-->a resistive load bank does that, imo.
Just resistive at 1.0pf would correspond to rated current. So 500kW. No need for reactance to get that. No need for the 1.25 times the rated kW.
I concur. 500kW is roughly 630 kVA @ 0.8pf-->the rating of the diesel engine prime mover!
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You do not agree that the load current in the generator windings will be greater at 630 kVA than at 500kW?
No.
Not if it is rated at 0.8 pf.
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