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Vacuum Contactors.


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I have 5 new Joslyn Clark vacuum contactors, nema size 6, 380V/224kw. What kind of aplications are they for? The vacuum means that there is no spark when they get closed and that increments the life of the contacts?

 

For any help, thanks in advance.

Chris.

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Hello Chris

 

Welcome to the forum, and what a good question!!

 

I am not sure what the claimed advantages for vacuum contactors are at low voltages. You are correct in the minimization of arcing contacts and I expect that this would increase the fault current interrupt capacity, plus it would be an advantage in a hazardous zone, but perhaps someone with more knowledge can give us the real answers.

 

Best regards,

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Typical reasons for using Vacuum Contactors in Low Voltage applications:

 

High dust applications, such as rock crushing etc., where even the best enclosure sealing cannot keep all of the contaminants out. Regular air-gap contactors fail relatively quickly in some areas, vacuum contactors are specified to avoid downtime.

 

High vibration or shock during transport, i.e. mobile equipment. When bouncing down the road a lot, air-gap contactors tend to get beaten to death without even being energized.

 

Highly sensitive noise applications. Vac. contactors use very little movement (about 1/8 in. or about 6mm) so when the contacts close they don't make a big Clank sound. For instance, elevator power controls in libraries or hotels where the elevator room is right next to a guest room.

 

Applications where the environment is highly susceptible to contamination from arcing contacts, i.e. semiconductor machinery. If the contactor opens under load and draws an arc, vaporized silver-oxide gets in to the machine air and can affect the silicon wafer surface.

 

Vac. contactors tend to be smaller than equivalent air-gap contactors, so when tight space is a problem they can often allow for a smaller enclosure.

"He's not dead, he's just pinin' for the fjords!"
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Now thats a reply from experience!!

 

I have only ever used vacuum contactors on MV, but the advantages put forward by Jraef certainly make sense to me, thanks for the insight.

 

Best regards,

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