COS PHI

Hello All,

I have an ABB drive ACH 400 series, one of the parameters is:
MOTOR COS PHI
nominal motor cos phi from the motor name plate range 0.50-0.99

Is this power factor? Can someone please explain? What effect does this have on drive? Motor?
Thanks!

Carrier frequency

Is there a formula for derating a drive when increasing carrier frequency?

Electronic Thermal Overload

Greetings all,
I need some help from the forum experts, I'm not an engineer just a field tech, so begins my problem; I had 2 60hp Franklin submersibles fail due to supply valves being shut, basically ran dry! Now I need to investigate so this can be prevented from happening again. These 2 motors are being controlled by 2 Hitachi Drives What I could use is some insight to setting the overload parameters in the drive, because IMO the drives should have tripped before the motor failed, am I correct in this assumption? Here's a link to the parameter set-up
http://www.hitachi.com/supportingdocs/indu...als/NB604XA.pdf

Parameters in question start on 3-29 "Electronic Thermal Overload Alarm Setting". I would be curiuos as to how some of you would set these up. Not that I don't stand behind our engineer 100%
;c;

THNK YOU.