uneven current
- Thread starter sparky59
- Start date
- Status
- Occupation
- Licensed Electrician
Doesn't sound bad. Are you having trouble with the it?
Phil Corso
Senior Member
- Location
- Boca Raton, Fl, USA
Sparky59...
Please provide corresponding Ph-Ph and Ph-Neutral measurements!
Regards, Phil Corso
Please provide corresponding Ph-Ph and Ph-Neutral measurements!
Regards, Phil Corso
- Occupation
- Licensed Electrician
+or - ten percent is what I was told by our motor guy. I've never had a case where all three read the same.
Phil Corso
Senior Member
- Location
- Boca Raton, Fl, USA
Sparky...
The Ampere-Imbalance-Factor (AIF) is about 9%. But, without knowing the corresponding Supply Voltage measurements one cannot say with assurance whether the problem is the supply or the motor!
If Supply voltage is the cause, then using the Rule-of-Thumb that Ampere-Imbalance is related to the square of Voltage-Imbalance, then the Voltage-Imbalance-Factor is 3%. The NEMA recommended maximum is 5%!
In conclusion,Yes, you may have a problem!
Regards, Phil
The Ampere-Imbalance-Factor (AIF) is about 9%. But, without knowing the corresponding Supply Voltage measurements one cannot say with assurance whether the problem is the supply or the motor!
If Supply voltage is the cause, then using the Rule-of-Thumb that Ampere-Imbalance is related to the square of Voltage-Imbalance, then the Voltage-Imbalance-Factor is 3%. The NEMA recommended maximum is 5%!
In conclusion,Yes, you may have a problem!
Regards, Phil
Cow
Senior Member
- Location
- Eastern Oregon
- Occupation
- Electrician
If the voltage is only slightly unbalanced it can create a much larger current unbalance.
A made a thread about a similar instance I had a couple years ago, but the search engine doesn't seem to be working right now so I can't link you to it.
A made a thread about a similar instance I had a couple years ago, but the search engine doesn't seem to be working right now so I can't link you to it.
Phil Corso
Senior Member
- Location
- Boca Raton, Fl, USA
Spark...
The value +,- 10% refers to a balanced supply voltages, not imbalance !!
Phil
The value +,- 10% refers to a balanced supply voltages, not imbalance !!
Phil
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Just FYI, if it is a submersible pump, the voltage balance factor is MUCH tighter than the NEMA standards, many are 2% and if you do not maintain it, you void the pump warranty (Franklin Pump is like that).
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