IEC question
IEC question
(OP)
Can anyone tell me what the minimum tripping voltage in % of nominal is for a DC powered circuit breaker in IEC territory? Thanks.
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
Download nowINTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
|
RE: IEC question
RE: IEC question
RE: IEC question
With regard to a low figure of 70% for breaker trip coil, it occurs only at the time of picking up of the breaker trip coil and is understandable considering huge magnitude of current that the trip solenoid would draw.
Typically a breaker trip coil burden would be 200W as against a couple of watts (at the most) of a protection relay.
It may also be noted that the high speed, high impedance trip relays like type MVAJH of Areva are designed to pick up and close the trip contacts positively even at 50% of rated DC voltage.
RE: IEC question
Unless a separate circuit is pulled for the relay, a relay installed at the breaker will see the full voltage drop. When retrofitting a microprocessor relay into a breaker cabinet that had electromechanical relays for example.
ANSI breakers are required to trip down to about 56% nominal. Sounds to me like the last gasp of a dying battery. But the relay is out at 80%.
Areva's 50% sounds a lot more reasonable. Shouldn't be that big a deal anymore with the wide ranging power supplies available.
Any input from the manufacturers? Is Davidbeach listening?