Solenoid valves
- Thread starter BrainBandAid
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BeanAnimal
Premium Member
ReefRatz... what makes you so sure that there is not exposed copper? If it is an AC valve it likely has a copper shading coil.
There are some direct acting solenoid valves that have "dry armatures"... but they are certainly not $10.
My money is simply on the fact that if you take the valve apart and look inside, you will find a little metal coil.
It may also be a Diaphragm type of valve... in that case all bets are off
There are some direct acting solenoid valves that have "dry armatures"... but they are certainly not $10.
My money is simply on the fact that if you take the valve apart and look inside, you will find a little metal coil.
It may also be a Diaphragm type of valve... in that case all bets are off
BeanAnimal
Premium Member
Ahh you posted before I replied...
Yest that looks like a diaphragm type of valve.
Another question... they usually don't work well (sprinkler valves) with any back pressure on them. I imagine that you have the RO/DI open ended?
Yest that looks like a diaphragm type of valve.
Another question... they usually don't work well (sprinkler valves) with any back pressure on them. I imagine that you have the RO/DI open ended?
BeanAnimal
Premium Member
Robby, you may not know what your looking at. What is the brand and model of the solenoid? Like I said, 99.9% of the directly actuated solenoid valves have a shading coil. If there is no coil, then the solenoid will hum or chatter in a rather anoying manner. It is simple matter of physics
If you found one with an encapsulated shading coil, then that is great.
If you found one with an encapsulated shading coil, then that is great.
stugray
Premium Member
Bean,
I have heard of the "shading pole" on an AC motor, so I have no reason to question the concept, but I think that most of us are questioning why the "shading coil" must be exposed to the fluid?
What prohibits the manufacturer from ensapsulating the coil rather than using exotic materials?
Stu
I have heard of the "shading pole" on an AC motor, so I have no reason to question the concept, but I think that most of us are questioning why the "shading coil" must be exposed to the fluid?
What prohibits the manufacturer from ensapsulating the coil rather than using exotic materials?
Stu
BeanAnimal
Premium Member
The shading coil of a direct acting solenoid is part of the "stop". The stop makes contact with the plunger. If you "encapsulate " it, then you move it further from the armature and severly weaken the effect. This in turn creates the need for a larger main coil and larger shading coil to produce the same amount of holding power with no buzz. I already stated that. So the most basic answer to the question of "why" is COST and SIZE.
Question the concept... I am not sure why you would. Like I said it is AC solenoids 101 and plenty of information is availabe via a simple google search. If there is no shading coil, then the solenoid will buzz and have very little holding power. The shading coils induced current smooth out the loss of magnetisim at and aproaching zero crossing.
Here is a cross section of a typical direct acting AC solenoid
www.reeflogix.com/images/hosted/solenoid_x_section.jpg
Honestly.. this is getting kind of silly. I don't so much mind the questions, but I fail to see why so many very bright people have such a hard time swallowing something so simple and common.
If you are still in doubt you can easily poke around a dozen of the manufacturers websites and look at the data sheets. They will list either a wetted COPPER or SILVER shading coil for ALL of their AC solenoid valves. As I have mentioned several times, you CAN find some exceptions, but they easily cost in the $200+ neighborhood per valve. Even the valves with the SILVER shading coils cost a lot.
If all else fails, call ASCO, Hayward, Norgren, etc... talk to a tech rep or engineer. They will gladly give you all of the details you ever wanted, and more.
How do I know? I have spent several years looking or and workign with these things. I have learned a lot from the web, manufacturers datasheets, and numerous calls to manufacturers in an attempt to find a suitable valve and educate myself.
LIke I said, Robby can disagree or "not want to argue" but the chances of him having found a CHEAP AC solenoid that does not have a wetted shading coil are slim to none. If he did find one, then of course we all want to know the OEM and model number, as it would be a great find.
As I also mentioned, I am not sure how much of a threat the copper is if used after the RO/DI. A lot of people use them that way. I am not worried about it.... but use DC valves anyway, as it is safer and just as easy. If anybody has any doubts, then the DC valves are the way to go. Of course a check of hte datasheet or call to the OEM is always a good idea to determine exactly what is wetted and what the the max duty cycle is.
Bean
Question the concept... I am not sure why you would. Like I said it is AC solenoids 101 and plenty of information is availabe via a simple google search. If there is no shading coil, then the solenoid will buzz and have very little holding power. The shading coils induced current smooth out the loss of magnetisim at and aproaching zero crossing.
Here is a cross section of a typical direct acting AC solenoid
www.reeflogix.com/images/hosted/solenoid_x_section.jpg
Honestly.. this is getting kind of silly. I don't so much mind the questions, but I fail to see why so many very bright people have such a hard time swallowing something so simple and common.
If you are still in doubt you can easily poke around a dozen of the manufacturers websites and look at the data sheets. They will list either a wetted COPPER or SILVER shading coil for ALL of their AC solenoid valves. As I have mentioned several times, you CAN find some exceptions, but they easily cost in the $200+ neighborhood per valve. Even the valves with the SILVER shading coils cost a lot.
If all else fails, call ASCO, Hayward, Norgren, etc... talk to a tech rep or engineer. They will gladly give you all of the details you ever wanted, and more.
How do I know? I have spent several years looking or and workign with these things. I have learned a lot from the web, manufacturers datasheets, and numerous calls to manufacturers in an attempt to find a suitable valve and educate myself.
LIke I said, Robby can disagree or "not want to argue" but the chances of him having found a CHEAP AC solenoid that does not have a wetted shading coil are slim to none. If he did find one, then of course we all want to know the OEM and model number, as it would be a great find.
As I also mentioned, I am not sure how much of a threat the copper is if used after the RO/DI. A lot of people use them that way. I am not worried about it.... but use DC valves anyway, as it is safer and just as easy. If anybody has any doubts, then the DC valves are the way to go. Of course a check of hte datasheet or call to the OEM is always a good idea to determine exactly what is wetted and what the the max duty cycle is.
Bean
BeanAnimal
Premium Member
BeanAnimal
Premium Member
Notice the copper ring
Without it the solenoid would buzz like a magnetic door strike.
Without it the solenoid would buzz like a magnetic door strike.
BeanAnimal
Premium Member
Ric A lot of us run them downstream of the RO/DI unit
My setup uses several, one for the ATO, one for the Change water, and eventually one for a spare water resevoir.
My setup uses several, one for the ATO, one for the Change water, and eventually one for a spare water resevoir.
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