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Do you have to derate the ATS48 Soft Starters if you mount them at high elevations?

Issue:
Do you have to derate the ATS48 Soft Starters if you mount them at high elevations?
 
Product Line:
Altistart ATS48
 
Environment:
All
 
Cause:
Derating for high altitude
 
Resolution:
Maximum operating altitude
3300 feet without derating. Above this, derate the nominal current by 2.2% for each additional 330 feet to the maximum of 6600 feet.

Here is an example:
40HP 460VAC Soft Starter is normally an ATS48D62Y however if you are going to use this unit at 6000 ft you will need to up size by 1 or more. So you will need to use a

ATS48D75Y for a 40HP 480VAC.
Here is why
3300 feet is basic rating without derating.
If you want 6000 feet - 3300 feet = 2700 feet
you have to Derate the for 2.2% each 330 additional feet
2700 ft / 330 ft = 8.1818 X 2.2%= 18% current derate of the product.
So if the Soft Starter is rated for 75 amps X 18%= derate of 13.5 amps
or 75amps minus 13.5 amps= 61.5 amps
so now your ATS48D75Y now only rated for 61.5 amps not 75 amps.
Derating Drives operating at 6000 ft will be as follows.
62 amp ATS48D62Y is rated for only 51 amps
75 amp ATS48D75Y is rated for only 61.5 amps this will match your 40 HP unit.
 

 
 
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