DP contactor coil.

[Jraef]

Well, if they could make one coil that could be used on multiple voltages why would they make two?

On second thought maybe they do and they are just charging more for the one labelled with the higher voltage. I might start testing all my coils with the highest voltage available.

Thewre is no difference in price based on the voltage rating.

 

[ActionDave]

Well, drat. I thought a corporate conspiracy had been discovered.

 

[mike7330]

Why, how did it work for so long? Any thing I miswired takes only seconds for the smoke to escape.

OH. isn't that true. But I don't know what your talking about? ;(

 

[hurk27]

H'mmm

Never thought about it but 240 volts divided by 709 ohms is .34 amps, while 480 volts divided by 709 ohms is .68 amps, and this is only till the armature is fully pulled in which the current will drop off, while I can see that a doubling of the current might cause the coil to over heat and the fact that the pull in will be much faster at 480 volts, once the armature is fully engaged the current would drop off and maybe to a level that would not burn up the coil, I have seen many relays that would take a very wide range of voltages on the coil, a look on Square D's web site might give us the hold in current verses the pull in current, I'll see if I can find it, I'll bet that coil wouldn't last too long if the contactor failed to pull in just once. I think the design of the coil is to allow it to not fail in the event of the armature being stuck. I remember many of the AB series 800 coils being dual voltage with jumpers to change the voltage.

You would think that a 480 volt coil would be double the ohms as a 240 volt coil? like 1418 ohms? or visa versa the 240 volt coil would be half of what a 480 coil is like 1500 ohms from the 3k he read from the 480 volt coil

 

[hurk27]

Wow what a run around on Schneider's web site, no where is the impedance of their coils listed, the only thing I found that relates to any load a coil is just for testing with a 9 volt battery:

NOTE: The resistance of this coil
cannot be measured with an
ohmmeter. A properly functioning coil,
when isolated from its control circuit,
will draw between 0.3 mA and 10 mA
(depending on its voltage rating) when
connected to a 9 V battery (polarity
unimportant).

From here

If an application needed a specific loading figure to build a control circuit from you would have to do your own measurements to figure out what load a coil would add to the control system, I could not find any chart that told me what the current would be for a given voltage coil in the 9998 series A coils.

With todays electronic control systems you think they would have some kind of a chart of the coil impedance to design from, I understand you can't get the correct impedance by using a ohm meter but you would think they would give you something to go by, at least the closing load and the sealing load, maybe Jim Dungar might know more on this?

 

[hurk27]

Well after extensive searching on their site I finally found something in their FAQ's

DA1V06 480 volt coil is 56va inrush and 6va sealed
DA1V09 208-240 volt coil is 56va inrush and 6va sealed

so with this the impedance would be doubled for the 480 coil, and the va would be also doubled using the 240 volt coil on 480 or 112va for inrush and 12va for sealed as we can see it should withstand the sealed va for a long time?
Am I missing something?
I could see if the coil was short cycled like more then 3 or 4 turn ons in a minute it would get hot and maybe fail but I don't think that would happen with an air compressor?

 

[Besoeker]

so with this the impedance would be doubled for the 480 coil, and the va would be also doubled using the 240 volt coil on 480 or 112va for inrush and 12va for sealed as we can see it should withstand the sealed va for a long time?
Am I missing something?

Possibly.
A wound coil with an iron core that is likely to saturate if the voltage is excessive. It that case, the VA would would not be a linear relationship.

 

[T.M.Haja Sahib]

One last point the OP is requested to carry out is checking the AWG of the magnetic wires of the suspected 240V coil and 'normal' 480V coil.

Even if the applied voltage of 480V is above its rated voltage,the coil can not be expected to fail by insulation breakdown due to 480V,because it would have withstood meggar voltage of 500V during routine tests earlier.

 

[ptonsparky]

One last point the OP is requested to carry out is checking the AWG of the magnetic wires of the suspected 240V coil and 'normal' 480V coil.

Even if the applied voltage of 480V is above its rated voltage,the coil can not be expected to fail by insulation breakdown due to 480V,because it would have withstood meggar voltage of 500V during routine tests earlier.

I don't happen to have a micrometer in my tool bag. A non-technical term that comes into mind is a "grunion". I am thinking about 1 1/2 to 2 grunions in diameter. Dang small in other words. I used 1000 DC.

 

[T.M.Haja Sahib]

I don't happen to have a micrometer in my tool bag. A non-technical term that comes into mind is a "grunion". I am thinking about 1 1/2 to 2 grunions in diameter. Dang small in other words. I used 1000 DC.

My intention is to confirm whether the magnetic wire of that '240V' coil had enough
cross sectional area to pass the current at 480V.

 

[ptonsparky]

My intention is to confirm whether the magnetic wire of that '240V' coil had enough
cross sectional area to pass the current at 480V.

Obviously, it did, or enough impedance to limit the current flow to a level that was safe for the time it was on.

 

[T.M.Haja Sahib]

Obviously, it did, or enough impedance to limit the current flow to a level that was safe for the time it was on.

In another post,it was said there was no cost difference between 240V and 480V coils.So the size of the magnetic wires used in both the coils might be the same;only the labeling is different.....