electrical contact

[bibi1964]

hi
what is mean in the contact the number 2
16(2) A 250 V

 

[Surefire01]

Most probably refering to max interruption capabilities: 16A for resistive load, 2A for inductive load.

 

[bibi1964]

hi
this is what is write in the data sheet


Switching capacity resistive
(ind. cos. j = 0,6) loads
16(2) A 250 V ~

what is mean?

 

[waross]

Is this a two pole switch?
Part number?
Link to the catalogue?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[bibi1964]

hi
this is the data sheet

 

[ScottyUK]

It's capable of switching 16A at 250V AC into a resistive load without inrush, but only 2A at 250V AC into a reactive load with a 0.6 power factor.

 

[bibi1964]

Thank you for your response

The current of this contact is for long operation or just when I switch the load?

 

[ScottyUK]

It's thermal rating is 16A continuous, it just isn't great at handling the more severe switching conditions found with a reactive load so the rating is reduced when switching with reactive loads.

 

[jraef]

I agree with ScottyUKs assessment of the wording, albeit not terribly clear. So what that is saying is that if you want to use it for something that has a motor, the motor current cannot be more than 2A, even though the thermal rating is 16A. So the only thing you can use it for at the full 16A rating, or really anything more than 2A, will be resistive loads, such as incandescent lights or electric heaters. Things with electronic power supplies are probably OK at some value over 2A, but not likely at the full 16A, depending on the nature of the power supply design.



" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[Skogsgurra]

Not even incandescent lamps. The cold/inrush current of a 300 W lamp will kill that contact quickly. I think that the only loads it can handle successfully are purely resistive.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[ScottyUK]

I agree skogs, I noted earlier that the 16A rating was "resistive without inrush" for exactly this reason. The handful of times I've used contactors to directly switch tungsten lighting I have used the AC-3 rating, not the AC-1 rating.

 

[jraef]

Inductive ratings of contacts have more to to with OPENING an inductive circuit because of the sustained arc, not so much the inrush current. Most contacts I have seen will include incandescent lighting loads under the same use category as resistive loads.

But, it’s likely a moot point because incandescent lamps are rapidly becoming an anachronism.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[waross]

My experience with persistent arcs across contacts and welded contacts bears out jraef's post. In one instance the persistent arc melted the silver alloy contact material which then flowed together and made a metallic path, extinguishing the arc. I found several neat little silver alloy hourglass shapes where the contacts used to be.
When you break an inductive circuit, there is an inductive "kick" from the back EMF of the collapsing magnetic field of the inductor.
If the current is too high or the power factor is too low for the current, the arc created on opening the circuit may not extinguish, It may last until the contact alloy melts and bridges the gap or it may last until the arc burns the arc path long enough to extinguish the arc or starts a fire.
Note: For inductive loads, not only is the current important but the power factor is also important.
DC may be worse than AC.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

No, Bill. It may not. It is.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.