synchronous motor- exciter field rotation
synchronous motor- exciter field rotation
(OP)
I have a question about the effects of changing the roation of the ac exciter field on a synchronous motor and how to tell which way is right, or if it matters at all...
i could post the nameplate stats, but i feel my test results are more relevant.
with the motor at 100% (360rpm) i have an exciter input amperage of 65, input voltage of 157ac, and a motor voltage of 3950-4000
reversing the exciter field voltage results in an exciter input amperage of 65, input voltage of 173ac, and a motor voltage of 3860-3880
the motor reaches its rated speed in both configurations.
test results on a diferent motor with the same specs show the same correlation
thanks for your time
i could post the nameplate stats, but i feel my test results are more relevant.
with the motor at 100% (360rpm) i have an exciter input amperage of 65, input voltage of 157ac, and a motor voltage of 3950-4000
reversing the exciter field voltage results in an exciter input amperage of 65, input voltage of 173ac, and a motor voltage of 3860-3880
the motor reaches its rated speed in both configurations.
test results on a diferent motor with the same specs show the same correlation
thanks for your time





RE: synchronous motor- exciter field rotation
I wouldn't think swapping the field polarity makes any difference. Is this difference repeatable?
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(2B)+(2B)' ?
RE: synchronous motor- exciter field rotation
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(2B)+(2B)' ?
RE: synchronous motor- exciter field rotation
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: synchronous motor- exciter field rotation
RE: synchronous motor- exciter field rotation
RE: synchronous motor- exciter field rotation
Seems to me that the resultant frequency in the AC windings on the rotor will concatenate [if I'm using the terminology in an acceptable way] either additively or subtractively; and I would ASSume that the manufacturer has designed these windings for sustained operation at only one of the two frequencies...so don't use the wrong one.
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: synchronous motor- exciter field rotation
RE: synchronous motor- exciter field rotation
My SWAG [scientific wild-a** guess] would be to use the configuration with the lower AC excitation voltage; less watts being consumed in the rotor circuitry, hence runs cooler, hence unit lasts longer. Reason for my SWAG is that in the first case the concatenation of field strength times speed is additive, therefore a higher machine terminal voltage is being derived. As a consequence less real power is required to be supplied to the field to develop roughly the same voltage.
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: synchronous motor- exciter field rotation
thanks for your time!
RE: synchronous motor- exciter field rotation
From what you are observing, I would expect that the first connection is correct. I'm basing this on the higher terminal voltage, which is indicating the motor is acting like a capacitor.
RE: synchronous motor- exciter field rotation
Bill
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"Why not the best?"
Jimmy Carter