Conductor sizing??

[petersonra]

I thought the tables had that built in with close to the worst PF. That is why the table is usually higher amperage than the actual motors.

I think the tables are high just because they were created long before anyone cared about motor efficiency. Modern motors are substantially lower in current for the same HP rating. Could be due to better PF among other things.

 

[Dennis Alwon]

I edited that post right away to this---- At the bottom of the table they say to use 1.1 and 1.25 for 90% and 80% PF respectively

 

[ramsy]

I see that at the bottom Table 430.250

 

[petersonra]

I edited that post right away to this---- At the bottom of the table they say to use 1.1 and 1.25 for 90% and 80% PF respectively

Take a closer look at what the note applies to.

 

[Dennis Alwon]

Take a closer look at what the note applies to.

Thank you.... I have never used it and just noticed it.

 

[petersonra]

Thank you.... I have never used it and just noticed it.

I don't recall ever running across a synchronous motor before.

 

[Dennis Alwon]

I don't recall ever running across a synchronous motor before.

At least you know what it is....hahaha

 

[petersonra]

At least you know what it is....hahaha

I have heard of one. Not sure of what it is or why one would use one.

 

[don_resqcapt19]

I have heard of one. Not sure of what it is or why one would use one.

One of the reasons is that you can use them for power factor correction as induction motors have lagging power factor and a synchronous motor can be operated at a leading power factor.

 

[topgone]

One of the reasons is that you can use them for power factor correction as induction motors have lagging power factor and a synchronous motor can be operated at a leading power factor.

Correct. We have one in my other life. Really helps us lessen our energy costs.