COMMENT 11-20 Table 430.250

[fmtjfw]

I'm looking for constructive criticism on the following, and if you think it is merited, support in the form of comments from you on 11-20 Table 430.250. Thanks, Jim Williams

4 Comment:

Table 430.250 Full-Load Current, Three-Phase Alternating-Current Motors
The following values of full-load currents are typical for motors running at speeds usual for belted motors and motors with normal torque characteristics.
The voltages listed are rated motor voltages. The currents listed shall be permitted for system voltage ranges of 110 to 120, 220 to 240, 440 to 480, and 550 to 1000 600 volts.

5 Statement of Problem and Substantiation.
Restore the previous value of 600 volts. The same current for motors that differ in voltage by about a factor of two is unlikely.

Adding a column may be appropriate for higher voltage motors.

It appears to be a case of search and replace run amuck.

 

[texie]

I think that was already corrected in later printings.

 

[fmtjfw]

good.

Where are the later printings?

 

[texie]

good.

Where are the later printings?

Good question. I just looked at 2 copies of the 2011 and they both have Table 430.250 correct. But I can't find the printing date.

 

[fmtjfw]

AHA!

AHA!

The text I have is from the 2014 DRAFT. There are about a zillion changes for 2014 which make the old 660V limit now 1000V. Some articles did not go along with the change and so there is a mish-mash of 600V and 1000V limits. The table 430.250 text that read "550 to 600" was I think, updated mindlessly to "550 to 1000".

All the text referenced in the COMMENT postings I've made are from the 2014 draft.

Sorry for the confusion