May I know how much current that this contactor can handles? - Electronic Circuits Projects Diagrams Free

wkyong · 18th August 2008, 09:21 AM

This is a ABB B50 brand contactor,it is written Ith=125A ,
IeAC-1=100A & not mentioned continuous current ,
I don't understand what do they mean & which one is the exact current that it can handles?
Thanks!!!

Diver300 · 18th August 2008, 05:54 PM

The current that the contactor can handle depends on how often the contactor is interupting the current, what current surges are expected when turning on and what voltage surges are expected when turning off.

The Ith = 125 A means that the thermal limit on the contactor is 125 A continuous without overheating. The resistance is such that the power from the heating with 125 A can be dissapated without any part getting too hot.

http://www.abbcontrol.fr/Appl-AC1/

&

http://www.abbcontrol.fr/Appl-AC3-4/

explain that Ie means:-

Quote:

Rated operational current of an apparatus taking into account voltage, frequency, duty and utilization category.

and AC-1 means

Quote:

Non-inductive or slightly inductive loads, resistance furnaces.

So that contactor shouldn't be used above 100 A in real-life situations, and probably at no more than 30 A or so on a motor.

I see you cross-posted on http://forum.allaboutcircuits.com/sh...ad.php?t=13743

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18th August 2008, 09:21 AM	(permalink)
wkyong	May I know how much current that this contactor can handles? This is a ABB B50 brand contactor,it is written Ith=125A , IeAC-1=100A & not mentioned continuous current , I don't understand what do they mean & which one is the exact current that it can handles? Thanks!!!