Posted 11 January 2007 - 04:12 PM
Finaly, is there a phisical diference betwen the contacts in a kvar contactor and a kw or hp contactor?
Fon any help, thenks in advance.
Posted 30 January 2007 - 02:18 PM
I am sorry, I've done smal mistake
Posted 30 January 2007 - 10:42 PM
UA..RA contactors for inrush currents exceeding 100 times the rated currents are now available up to 80 kvar. The UA..RA contactors are equipped with a special front mounted contact block which ensures the insertion of damping resistors in each phase, limiting the peak current at energization of capacitor banks. The contactors UA16..RA up to UA75..RA were released in June this year, and now the UA..RA range is completed by the addition of UA95..RA for 70 kvar and UA110..RA for 80 kvar.
As indicated above, contactors designed for connecting power factor correction capacitors must withstand high inrush current compared to the continuous current. Motor starting contactors must withstand moderate inrush current, but more importantly, they must break locked rotor current in the event that the motor stalls and the overload relay de-energizes the contactor. They may not be physically different, but they may have different ratings according to the duty. They may also may have different certifications indicating which code requirements they meet.
Posted 31 January 2007 - 01:08 AM
Posted 31 January 2007 - 01:58 AM
Unfortunately, a lot of people had no idea what they were reading and misapplied the contactors.
Dear Mr. Jraef,
I am also in those people but want to know more about contactor rating (AC1, AC2, AC3.....). We have designed a PF correction panel for our new project and used "National" brand FC-85 contactors for switching 50kvar capacitors as I didn't know about kvar rating of contactor.
I would be very thankful to you or any member who provide me any link which help me in understanding the contactor's rating.
"Don't assume any thing, always check/ask and clear yourself".
Posted 31 January 2007 - 03:21 PM
The specific contactors have printed this particulary numbers.
We have here 380V. How can i calculate the kW rating that this contactor can handle starting from the 60 kVAr?
Posted 31 January 2007 - 07:53 PM
I don't know about other brands, but if you can get hold of a Siemens catalog, look up the 3RT16 contactors for a description of how they work and a link to wiring diagrams, ratings etc.
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