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12vdc 4.5amp QUESTION

K

Ketsup

Jan 1, 1970
0
I have a small fan that is used to exhaust air from a work station. It runs
on 12v DC 4.5 amps.

I was told that there are four ways to effectively power this fan on
household current, and do so safely.

One was to buy a power converter from Radio Shack (the cheap ones) and wire
it to the 12v.

Two, was to buy a power pack- the kind that is used to jump start batteries,
and use that by wireing a cigarette plug to the end of the fan and plug it
into the power pack and basically leave the power pack plugged in and run
the fan off of the pack all the time (24/7).

Three was to use the power supply used TO charge this battery jumper pack-
which is rated at 13.5v 300 amps.

Four was to wire the fan to a power supply used for personal computers.

Which would be safe, cheap, and effective?

Thank you!
 
T

TimPerry

Jan 1, 1970
0
Ketsup said:
I have a small fan that is used to exhaust air from a work station. It runs
on 12v DC 4.5 amps.

I was told that there are four ways to effectively power this fan on
household current, and do so safely.

One was to buy a power converter from Radio Shack (the cheap ones) and wire
it to the 12v.

Two, was to buy a power pack- the kind that is used to jump start batteries,
and use that by wireing a cigarette plug to the end of the fan and plug it
into the power pack and basically leave the power pack plugged in and run
the fan off of the pack all the time (24/7).

Three was to use the power supply used TO charge this battery jumper pack-
which is rated at 13.5v 300 amps.

Four was to wire the fan to a power supply used for personal computers.

Which would be safe, cheap, and effective?

Thank you!

replace fan with AC fan and wire to wall outlet.


move 12 V DC fan to motor vehicle.
 
K

Ketsup

Jan 1, 1970
0
Replacing fan with AC fan NOT a possibility to consider at the time, this DC
fan is only functional device sutible for application- mostly in the design
and utility of the fan.- but "thanks"...
 
P

Palindr☻me

Jan 1, 1970
0
Ketsup said:
I have a small fan that is used to exhaust air from a work station. It runs
on 12v DC 4.5 amps.

I was told that there are four ways to effectively power this fan on
household current, and do so safely.

One was to buy a power converter from Radio Shack (the cheap ones) and wire
it to the 12v.

Two, was to buy a power pack- the kind that is used to jump start batteries,
and use that by wireing a cigarette plug to the end of the fan and plug it
into the power pack and basically leave the power pack plugged in and run
the fan off of the pack all the time (24/7).

Three was to use the power supply used TO charge this battery jumper pack-
which is rated at 13.5v 300 amps.

Four was to wire the fan to a power supply used for personal computers.

Which would be safe, cheap, and effective?

Thank you!
Just go to Radio Shack and buy a suitably rated nominal volt power
supply and connect the fan. It will be safe, cheap, effective and easy
to connect. One of the types designed to allow car equipment to be used
in the home, if it is rated at 4.5 A, at least, will be fine.

Using a computer power supply with adequate rating could be ok - but you
would need the right connectors to wire it up and not all of them are
suitable for connecting only to a 12 V load. They are also designed to
be mounted inside a computer case and wouldn't be as safe or as tidy as
a unit intended to be self contained.

Using a power pack is an unnecessary expense. If you do, make sure the
outlet is fused appropriately. There is enough energy stored in one of
these units to start a nice warm fire, very quickly.

The charger unit for the power pack may not be rated to provide 4.5 A.
These normally charge over many hours at a relatively low current. Even
if it is rated at 4.5A output, it may be highly unregulated and produce
too high a voltage for your needs. The panel on the charger should tell
you its output voltage and continuous current rating. It may also need a
special connector for the fan wire. So, it may or may not do the job.

So, I would stick to a nominal 12 volt 4.5A regulated supply from Radio
Shack, or equivalent.
 
T

TimPerry

Jan 1, 1970
0
Ketsup said:
Replacing fan with AC fan NOT a possibility to consider at the time, this DC
fan is only functional device sutible for application- mostly in the design
and utility of the fan.- but "thanks"...

use a suitable 12 V power supply.

radio shack power supplies: not suitable for any industrial application (in
my opinion) based on experience.

the expense of a (electronically) regulated supply is unnecessary.

battery chargers make terrible supplies (usually). they charge batteries
well and that's about it. way too high no load voltage to be useful and
high internal resistance in the secondary.

for 7/24 operation use a supply that is rated for twice the operating
current (at a minimum).


wire the fan to the supply (no plastic automotive type plug - they melt)
 
K

Ketsup

Jan 1, 1970
0
To clarify the size of the fan, here is a link to a similar fan- it is the
only thing I could find that would effectively remove the fumes from the
area in which I am working-

http://www.amback.com/ProductDetails.aspx?ProductID=60146


It says that it draws 4.5 amps- but I was wondering if this only acts as
protection from surges when intially started, but then draws fewer amps as
the motor runs.
 
P

Palindr☻me

Jan 1, 1970
0
Ketsup said:
To clarify the size of the fan, here is a link to a similar fan- it is the
only thing I could find that would effectively remove the fumes from the
area in which I am working-

http://www.amback.com/ProductDetails.aspx?ProductID=60146


It says that it draws 4.5 amps- but I was wondering if this only acts as
protection from surges when intially started, but then draws fewer amps as
the motor runs.

Yep, look in Radio Shack for a power supply designed to run car
equipment off the mains supply - typically used for powering cb radios
and the like. That will do it nicely, if it is rated at 4A or so continuous.

You could just use a car battery charger - which will be cheaper. Some
need to detect the battery voltage before producing power - you don't
want one of those. The fan is intended for battery systems which produce
voltages of the sorts of value you will get from a charger - so a
charger should work fine.

You can also get dc output switched mode power supplies intended to
power 12V domestic halogen lights. They are very lightweight and very
cheap in the UK - but make sure you get one with dc out. I bought some
100W ones at around 8GBP each. They are fine for driving motor loads as
they are designed to cope wih high starting currents.

Sue


 
P

PCK

Jan 1, 1970
0
TimPerry said:
use a suitable 12 V power supply.

radio shack power supplies: not suitable for any industrial application
(in
my opinion) based on experience.

the expense of a (electronically) regulated supply is unnecessary.

battery chargers make terrible supplies (usually). they charge batteries
well and that's about it. way too high no load voltage to be useful and
high internal resistance in the secondary.

for 7/24 operation use a supply that is rated for twice the operating
current (at a minimum).


wire the fan to the supply (no plastic automotive type plug - they melt)
200% probally overkill i would give it 125% or max 150%
 
A

Anthony Guzzi

Jan 1, 1970
0
Ketsup said:
I have a small fan that is used to exhaust air from a work station. It runs
on 12v DC 4.5 amps.

I was told that there are four ways to effectively power this fan on
household current, and do so safely.

One was to buy a power converter from Radio Shack (the cheap ones) and wire
it to the 12v.

Two, was to buy a power pack- the kind that is used to jump start batteries,
and use that by wireing a cigarette plug to the end of the fan and plug it
into the power pack and basically leave the power pack plugged in and run
the fan off of the pack all the time (24/7).

Three was to use the power supply used TO charge this battery jumper pack-
which is rated at 13.5v 300 amps.

Four was to wire the fan to a power supply used for personal computers.

Which would be safe, cheap, and effective?

Thank you!


Another option is to go down to Home Depot and buy a power supply for
Path Lighting, most of those use 12vDC.
 
T

TimPerry

Jan 1, 1970
0
wire the fan to the supply (no plastic automotive type plug - they melt)
200% probally overkill i would give it 125% or max 150%

if it an R-S transformer make it 400% .... and fuse the heck out of it....
and make sure the enclosure is fireproof.
 
J

John G

Jan 1, 1970
0
Anthony Guzzi said:
Another option is to go down to Home Depot and buy a power supply for
Path Lighting, most of those use 12vDC.

AC in my experience. Why would you spend money on a rectifier for just
lights.
12 volts maybe but not good for a DC fan.
 
A

Al

Jan 1, 1970
0
Ketsup said:
I have a small fan that is used to exhaust air from a work station. It runs
on 12v DC 4.5 amps.

I was told that there are four ways to effectively power this fan on
household current, and do so safely.

One was to buy a power converter from Radio Shack (the cheap ones) and wire
it to the 12v.

Two, was to buy a power pack- the kind that is used to jump start batteries,
and use that by wireing a cigarette plug to the end of the fan and plug it
into the power pack and basically leave the power pack plugged in and run
the fan off of the pack all the time (24/7).

Three was to use the power supply used TO charge this battery jumper pack-
which is rated at 13.5v 300 amps.

Four was to wire the fan to a power supply used for personal computers.

Which would be safe, cheap, and effective?

Thank you!

Find a 12.6 volt filament transformer rated for twice your running
current. Attached to it full wave bridge rectifier rated at four times
your running current. Put them in a nice box with a power switch and a
circuit breaker rated at 125% of your running current; it will handle
the starting surge.

The hefty transformer may be hard to find for a reasonable price; it's
cost alone may equal the price of your fan. Or go surplus shopping at
places like MPJA (http://www.mpja.com/), or Electronics Goldmine, or the
like and look for a DC supply. A 12VDC supply rated for 4.5 amps may be
quite expensive if it is regulated.

The best best would be to buy a 12VDC 6amp auatomotive trickle charger.
But you will pay at least the price of your fan for that.

Al
 
K

Ketsup

Jan 1, 1970
0
I wish to thank all of you for your input on this situation!
It seems I have a few options to consider, now the only issue is finding the
materials that you specified to do the job- both cheaply and safely!!

As far as the cost to run the fan equalling the cost of the fan itself, not
a real issue- in that, the other options I had recieved from electricians in
my area were at least three times the cost of the fan itself.

I have considered using fan that is AC- but none I have found have the CFM
rating of this powerful little fan, and even then- it was quoted that the
fans do not pull air, but only move air already present in the tube- not
creating a vacum like effect but only moving the air.

Since the work area I am working in is not air tight, a vacum of great
intensity is required to move the fumes away from me- that is why I chose
this fan- as a plus- it was relatively cheap. I am mostly looking at the
design of the fan itself and the propulsion of the blades as the main factor
for going through all of the issues that circumvent using this piece of
equipment- ie. the ones that you have all addressed in helping find a way to
power this little "sucker"- yes, pun intended! :)

Thank you all again, you have been VERY helpful!!!
 
T

TimPerry

Jan 1, 1970
0
Ketsup said:
I wish to thank all of you for your input on this situation!
It seems I have a few options to consider, now the only issue is finding the
materials that you specified to do the job- both cheaply and safely!!

As far as the cost to run the fan equalling the cost of the fan itself, not
a real issue- in that, the other options I had recieved from electricians in
my area were at least three times the cost of the fan itself.

I have considered using fan that is AC- but none I have found have the CFM
rating of this powerful little fan,

230 CFM is pretty small (at least in my viewpoint) i work with much larger
units used to cool vacume tubes.

here is a 450 CFM for $15 http://www.fairradio.com/fans.htm (plus shipping)

for the real big stuff check out http://www.comairrotron.com/

even a little equipment cooling fan can do 330 CFM
http://www.lytron.com/fans/tarzan.htm


and even then- it was quoted that the
fans do not pull air, but only move air already present in the tube- not
creating a vacum like effect but only moving the air.
you can have one without the other... no pressure differential no movement

Since the work area I am working in is not air tight, a vacum of great
intensity is required to move the fumes away from me- that is why I chose
this fan- as a plus- it was relatively cheap. I am mostly looking at the
design of the fan itself and the propulsion of the blades as the main factor
for going through all of the issues that circumvent using this piece of
equipment- ie. the ones that you have all addressed in helping find a way to
power this little "sucker"- yes, pun intended! :)

Thank you all again, you have been VERY helpful!!!

i suspect that if this low cost unit is used for any lengh of time you will
be replacing it on a regular basis.
 
K

Ketsup

Jan 1, 1970
0
Thanks to a suggestion from this board- would this device would be
appropiate?

http://www.wallcoinc.com/PSR_4C_4_Amp_Regulated_12VDC_Power_Supply_with_Ci_p/psr-4c.htm

States the following about the device;

4 Amp Regulated 12V DC Power Supply with Cigarette Lighter Adapter
(PSR-4C)
Our 12 volt 4 amp power supply is regulated and has filtered outputs. It
features a 5 amp surge, cigarette lighter adapter, built-in front panel,
fuse and auto reset circuit breaker overload protection, heavy duty 3 prong
grounded AC power cord, and universal binding posts. It has a 117V AC 60 Hz
input and a 12V DC ouput with a 4 amp constant and 5 amp surge.

Technical Specifications Input 117V AC .60 Hz

Output 12V DC . 4 Amp Constant, 5 Amp Surge

Size 2-5/5"(H) X 4-14" (W) X 7-1/2"(D)

Weight 4 lbs


Here is the link to the fan again-

http://www.amback.com/ProductDetails.aspx?ProductID=60146
 
P

Palindr☻me

Jan 1, 1970
0
Ketsup said:
Thanks to a suggestion from this board- would this device would be
appropiate?

http://www.wallcoinc.com/PSR_4C_4_Amp_Regulated_12VDC_Power_Supply_with_Ci_p/psr-4c.htm

States the following about the device;

4 Amp Regulated 12V DC Power Supply with Cigarette Lighter Adapter
(PSR-4C)
Our 12 volt 4 amp power supply is regulated and has filtered outputs. It
features a 5 amp surge, cigarette lighter adapter, built-in front panel,
fuse and auto reset circuit breaker overload protection, heavy duty 3 prong
grounded AC power cord, and universal binding posts. It has a 117V AC 60 Hz
input and a 12V DC ouput with a 4 amp constant and 5 amp surge.

Technical Specifications Input 117V AC .60 Hz

Output 12V DC . 4 Amp Constant, 5 Amp Surge

Size 2-5/5"(H) X 4-14" (W) X 7-1/2"(D)

Weight 4 lbs


Here is the link to the fan again-

http://www.amback.com/ProductDetails.aspx?ProductID=60146

I would be happy to use one of these. It has an auto-reset
circuit breaker which will protect things if the fan is slow
to start or has sucked something in to its blades. If the
fan had been a lot bigger, with more rotational mass, the
starting current could have been a problem but with small
fans like this, combined with an auto-reset thermal circuit
breaker, it won't be an issue. Enjoy.
 
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