I am into a project that is line powered but needs a 12VDC fan, for compactness and size.
So the dilemma is what means to derive the 12VDC/200Ma for the fan:
I have the following options in mind, in no order of preference:
Conventional transformer power supply
Direct line power with series dropping resistor and rectification
Direct line power with series capacitor and rectification.
Conventional line rectification with a high voltage regulator (TL783)
Conventional line rectification with zener pre-regulation and a common 3 termnal regulatot (LM7812)
Notes:
The power supply must be cost effective compared to off the shelf units
There is always an issue using non-isolated line power, but this fan is inside a grounded enclosure.
Open for comments or more options!
Thanks,
Len
12VDC FROM 120 VAC (Solved)
12VDC FROM 120 VAC (Solved)
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
- Janitor Tzap
- Posts: 1714
- Joined: Sat Aug 12, 2006 5:17 pm
- Contact:
Re: 12VDC FROM 120 VAC DILEMMA
Wait.......
What is the physical size needed for the fan?
If it isn't too small, you could still use a small AC fan.
Signed: Janitor Tzap
What is the physical size needed for the fan?
If it isn't too small, you could still use a small AC fan.
Signed: Janitor Tzap
Re: 12VDC FROM 120 VAC DILEMMA
Hi,
The fan is like a common axial PC fan, no tach leads, just power. It is 80 x 80 mm but only 15mm thick, and draws 180ma.
Here it is:https://www.arrow.com/en/products/od801 ... orion-fans
There is no room for a thicker fan, and the enclosures are already tooled for the 80mm size.
What happened is that that the older model had a 12VDC power supply, for other reasons, so it powered the fan.
This project has no need for DC except for the fan, so a dedicated supply is needed. This is a low quantity need, so building them is not an issue...
I looked all over for a 120VAC fan and in that size 25mm was all that was found. Your interest is appreciated, and if you find a gem under a rock, let me know!
Of the power supply design ideas I presented, do you favor one over the other? Since this is a low quantity need, building them is not an issue.
Thanks,
Len
The fan is like a common axial PC fan, no tach leads, just power. It is 80 x 80 mm but only 15mm thick, and draws 180ma.
Here it is:https://www.arrow.com/en/products/od801 ... orion-fans
There is no room for a thicker fan, and the enclosures are already tooled for the 80mm size.
What happened is that that the older model had a 12VDC power supply, for other reasons, so it powered the fan.
This project has no need for DC except for the fan, so a dedicated supply is needed. This is a low quantity need, so building them is not an issue...
I looked all over for a 120VAC fan and in that size 25mm was all that was found. Your interest is appreciated, and if you find a gem under a rock, let me know!
Of the power supply design ideas I presented, do you favor one over the other? Since this is a low quantity need, building them is not an issue.
Thanks,
Len
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
- Janitor Tzap
- Posts: 1714
- Joined: Sat Aug 12, 2006 5:17 pm
- Contact:
Re: 12VDC FROM 120 VAC DILEMMA
I would suggest you go with a Halfwave Power Supply.Lenp wrote:Hi,
The fan is like a common axial PC fan, no tach leads, just power. It is 80 x 80 mm but only 15mm thick, and draws 180ma.
Here it is:https://www.arrow.com/en/products/od801 ... orion-fans
There is no room for a thicker fan, and the enclosures are already tooled for the 80mm size.
What happened is that that the older model had a 12VDC power supply, for other reasons, so it powered the fan.
This project has no need for DC except for the fan, so a dedicated supply is needed. This is a low quantity need, so building them is not an issue...
I looked all over for a 120VAC fan and in that size 25mm was all that was found. Your interest is appreciated, and if you find a gem under a rock, let me know!
Of the power supply design ideas I presented, do you favor one over the other? Since this is a low quantity need, building them is not an issue.
Thanks,
Len
Since It is only powering just the Fan and nothing else.
Or
Problem with the Halfwave is RF noise and heat being generated.
I haven't found a AC FAN that thin so far.
I still need too check several surplus places.
Signed: Janitor Tzap
- dacflyer
- Posts: 4752
- Joined: Fri Feb 08, 2002 1:01 am
- Location: USA / North Carolina / Fayetteville
- Contact:
Re: 12VDC FROM 120 VAC DILEMMA
what about a cheap SMPS ( the new wall warts ) i get em all the time at flea markets for a dollar or 2.. just look in the
junk bins..
junk bins..
Re: 12VDC FROM 120 VAC DILEMMA
I can't use surplus or cast off components. This has to be a solid design with repeatability and documentation.
A $2 special from 'Sam's Transformemporium' may be a great buy, but it will not pass muster.
Like everyone else, I have bulging bin fill of wall warts, of any description, and if if was for one of a kind, it would be done and no need to make the post.
I am trying to stay away from a transformers if possible. If you priced them recently you'll know why. A Triad 12V 0.35A is $10 in singles! I buy quality switchers with a 2 year warranty, A universal input, and 60VA output unit for $13 in singles, and off brands are even less. Copper is out of sight again, and aside from that, a transformer makes it too easy!
I doubt if the brushless fans would even like the unfiltered ragged half wave power:razz:\
Len
A $2 special from 'Sam's Transformemporium' may be a great buy, but it will not pass muster.
Like everyone else, I have bulging bin fill of wall warts, of any description, and if if was for one of a kind, it would be done and no need to make the post.
I am trying to stay away from a transformers if possible. If you priced them recently you'll know why. A Triad 12V 0.35A is $10 in singles! I buy quality switchers with a 2 year warranty, A universal input, and 60VA output unit for $13 in singles, and off brands are even less. Copper is out of sight again, and aside from that, a transformer makes it too easy!
I doubt if the brushless fans would even like the unfiltered ragged half wave power:razz:\
Len
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
Re: 12VDC FROM 120 VAC DILEMMA
Probably saw some of these transformerless AC-to-DC circuits:
http://www.brighthubengineering.com/diy ... ly/#imgn_2
http://www.brighthubengineering.com/diy ... ly/#imgn_2
WA2RBA
Re: 12VDC FROM 120 VAC DILEMMA
DUMB ME...DILEMMA DONE!
After all is said and done, I scrapped the fan power DIY attitude and found the best answer.
Here is a PCB mount SMPS, 12V/250ma, with a ton of features and approvals, all for $5 in singles!!!
And, it is stocked on this side of the pond.
Here's the gem ...http://www.trcelectronics.com/View/Mean ... 3-12.shtml
After all is said and done, I scrapped the fan power DIY attitude and found the best answer.
Here is a PCB mount SMPS, 12V/250ma, with a ton of features and approvals, all for $5 in singles!!!
And, it is stocked on this side of the pond.
Here's the gem ...http://www.trcelectronics.com/View/Mean ... 3-12.shtml
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
Re: 12VDC FROM 120 VAC (Solved)
that's probably essentially what is inside newer wall warts. good choice
Re: 12VDC FROM 120 VAC (Solved)
Now I see them everywhere-
http://www.digikey.com/product-detail/e ... -ND/658557
http://www.digikey.com/product-detail/e ... -ND/658557
WA2RBA
Re: 12VDC FROM 120 VAC (Solved)
Hi, and thanks for your comments.
Yes, they are like that new 'special' car you buy, then an identical one pulls up next to you a block from the dealer!
I saw the model you linked to, and a look at the application sheet shows it needs a fair amount of support architecture. I also don't care for its high riding profile with the SIP arrangement. The unit it will be used in is shipped worldwide so I question that mounting integrity without a silicone blob to nail it to the board. Not that it matters, but the input voltage is also lower. (170VAC)
The Meanwell unit is a low profile rectangular package with 4 active pins and 1 dummy locator pin. It is plug and play. No support components needed unless you want to fuse it, and its input is 80 to 370V. $5 in singles, stocked locally, 2 work days from order to door and then kick in a factory 3 year warranty.....
The difference between crazy and eccentric is...An eccentric has money!
Yes, they are like that new 'special' car you buy, then an identical one pulls up next to you a block from the dealer!
I saw the model you linked to, and a look at the application sheet shows it needs a fair amount of support architecture. I also don't care for its high riding profile with the SIP arrangement. The unit it will be used in is shipped worldwide so I question that mounting integrity without a silicone blob to nail it to the board. Not that it matters, but the input voltage is also lower. (170VAC)
The Meanwell unit is a low profile rectangular package with 4 active pins and 1 dummy locator pin. It is plug and play. No support components needed unless you want to fuse it, and its input is 80 to 370V. $5 in singles, stocked locally, 2 work days from order to door and then kick in a factory 3 year warranty.....
The difference between crazy and eccentric is...An eccentric has money!
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
Re: 12VDC FROM 120 VAC (Solved)
Good find !! Dontcha love it when a plan comes together !!
Re: 12VDC FROM 120 VAC (Solved)
Remember, all plans come together.
Some good, and the others, we don"t talk about!
Some good, and the others, we don"t talk about!
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
Who is online
Users browsing this forum: No registered users and 0 guests