PWM Motor Speed Controller Regulator - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-15-2014, 11:10 PM   #1
Senior Member
 
Night Sailor's Avatar
 
Name: Conrad
Trailer: Bigfoot 3000 & Barth "slide-in" truck camper
Connecticut
Posts: 958
PWM Motor Speed Controller Regulator

Someone recommended one of these as an option for fine control of fan speed and reduced power draw. I wish I could remember who suggested it so I could thank him.

I thought it was a fine idea; so I bought two.

I tested one out today on my Fantastic Fan and found it reduced the power draw slightly on high and on low settings it was about the same draw (slightly less )as a low fan setting of my fantastic fan.

I wired it in such that I preserved the directional capability of the fan and bypassed the three speed switch while making it easy to restore that in case the PWM circuit board craps out.

What I liked best about it was the near silent operation and the extremely fine control of the speed.

My fantastic fan had a three speed switch which had resistance coils which I could feel getting hot which means wasted energy. I

wish if taken notes on the current draw as I'm going by memory. I believe it drew about .5-.6 A more on high using the three speed switch and perhaps .1A more on low.

While I would like to modify my other (bathroom) fan, I decided to wait to change it to a better quality fan before patching in my other PWM controller I bought. I can see myself buying more of these for other DC fan applications.

I concluded a thermostat would be ideal enhancement as a temperature threshold to kick it on at an ear silent speed would keep my camper cooler in the morning without waking me up.
__________________

Night Sailor is offline   Reply With Quote
Old 06-16-2014, 12:01 AM   #2
Member
 
Name: Ron
Trailer: 2004 trillium outback 13ft
Alaska
Posts: 41
Registry
Thanks for the report. I purchased one that I think is the same as you have (from china?) and am getting ready to install it. Any thoughts on the best location? How did you preserve the directional capability? It seems like the board input has a polarity. I'll have to make a wiring diagram of what it is and will probably see what the situation is then.
Glad to hear that the control works well. These fans are overkill for a small egg...they can almost pop your ears if the window isn't open enough!
__________________

Ak Ron is offline   Reply With Quote
Old 06-16-2014, 12:48 AM   #3
Senior Member
 
Name: Frank
Trailer: Casita
California
Posts: 259
Maybe he put the control in the main 12 vdc supply which doesn't change polarity. Do you suppose?
Frank
frankcfx is offline   Reply With Quote
Old 06-16-2014, 07:56 AM   #4
Senior Member
 
Night Sailor's Avatar
 
Name: Conrad
Trailer: Bigfoot 3000 & Barth "slide-in" truck camper
Connecticut
Posts: 958
I hooked up the device ground to Input ground and the "+12v" to the output of the fuse. I used make and female spade connectors so that I could reverse it if I needed the original fan control back and drew on the inside with a sharpie so that anyone could bypass it in seconds.

By the way DC is fed to the board with a connector which was not provided. I had a connector with wire that was a little lighter gauge than the supply but large enough to carry the load. I debated soldering leads directly to the board.

I secured the wires and board to the fan shroud with duct tape. I used hot glue to secure the board.
Night Sailor is offline   Reply With Quote
Old 06-16-2014, 09:26 AM   #5
Member
 
Name: Ron
Trailer: 2004 trillium outback 13ft
Alaska
Posts: 41
Registry
Thanks Frank and Conrad. I understand it now. I'll do mine soon. Good idea to make it able to go back to the switch as I don't know the longevity of this little circuit board. I can't believe that someone can make this and ship it from China all for less than $4!
Ak Ron is offline   Reply With Quote
Old 06-16-2014, 09:42 AM   #6
Senior Member
 
David Tilston's Avatar
 
Name: Dave W
Trailer: Trillium 4500 - 1977, 1978 (2), 1300 - 1977, 1973, and a 1972
Alberta
Posts: 5,849
Registry
I believe it was me that made the original suggestion:
http://www.fiberglassrv.com/forums/f...tml#post459872

I purchased the 10A vs the 3A version. It is bigger, but it has terminals for both the 12 DC in and the fan output. I plan to install it in the kitchen cupboard with the speed control knob sticking out.
6V 12 24V 10A Pulse Width Modulator PWM DC Motor Speed Control Switch Controller | eBay

Since it was only $1 more, I figured it was worth it.

The one that I suggested is also pictured below:
Adjustable Regulator Pulse Width PWM DC Motor Speed Controller Switch 6V 28V 3A | eBay

I think I would have been tempted to de-solder the connector and solder the wires directly.
Attached Thumbnails
Clipboard01.jpg   Clipboard02.jpg  

David Tilston is offline   Reply With Quote
Old 06-16-2014, 10:02 AM   #7
Senior Member
 
Night Sailor's Avatar
 
Name: Conrad
Trailer: Bigfoot 3000 & Barth "slide-in" truck camper
Connecticut
Posts: 958
Thanks for the info. I might just re solder it as I'd like to have both connectors for other purposes.
Night Sailor is offline   Reply With Quote
Old 06-16-2014, 10:04 AM   #8
Senior Member
 
Night Sailor's Avatar
 
Name: Conrad
Trailer: Bigfoot 3000 & Barth "slide-in" truck camper
Connecticut
Posts: 958
I think I like the other control board better. Nicer connectors, better heat dissipation.

It is a fun modification, cheap, and easy while providing a real benefit perfect speed control.
Night Sailor is offline   Reply With Quote
Old 06-16-2014, 10:07 AM   #9
Senior Member
 
David Tilston's Avatar
 
Name: Dave W
Trailer: Trillium 4500 - 1977, 1978 (2), 1300 - 1977, 1973, and a 1972
Alberta
Posts: 5,849
Registry
Quote:
Originally Posted by Night Sailor View Post
I think I like the other control board better. Nicer connectors, better heat dissipation.
Yah, but substantially larger. Did you get your PWM in the fan, or mount it remotely?
David Tilston is offline   Reply With Quote
Old 06-16-2014, 10:15 AM   #10
Senior Member
 
Night Sailor's Avatar
 
Name: Conrad
Trailer: Bigfoot 3000 & Barth "slide-in" truck camper
Connecticut
Posts: 958
There were four corners to the fan shroud. One was empty so I used that corner for board and knob.
Night Sailor is offline   Reply With Quote
Old 06-16-2014, 11:05 AM   #11
Senior Member
 
David Tilston's Avatar
 
Name: Dave W
Trailer: Trillium 4500 - 1977, 1978 (2), 1300 - 1977, 1973, and a 1972
Alberta
Posts: 5,849
Registry
I think with the larger one, that may not be possible. I am planning on using it with an older 3 speed Maxxfan, (4.4A). I am worried that the fluctuating voltage may be a problem for the electronic thermostat. If I can't fit it in the fan, then I will probably have to run the final motor output back to the kitchen cupboard where the PWM will be installed, so six wires to the fan. I will probably get some Belden three pair cable.
David Tilston is offline   Reply With Quote
Old 06-16-2014, 11:17 AM   #12
Senior Member
 
Name: Drew
Trailer: Trillium Outback - 2004
Alberta
Posts: 106
Registry
For another idea, I added a resistor and a switch and turned mine into a 6 speed. I got the idea from this guys mod:

Fan-Tastic Vent mod from 3-speeds to 6-speeds - All Terrain Camper Discussions - Wander the West

So far it's worked well. I went with a resistor that brought my slower speeds almost all under an amp. Truthfully because of the size of my trailer I almost never take it off the lower setting which draws around .75 amps unless I'm cooking bacon.
__________________
Where weíre going, we donít need a plug-in.
multi-task is offline   Reply With Quote
Old 06-16-2014, 11:33 AM   #13
Senior Member
 
David Tilston's Avatar
 
Name: Dave W
Trailer: Trillium 4500 - 1977, 1978 (2), 1300 - 1977, 1973, and a 1972
Alberta
Posts: 5,849
Registry
The only down side to using a resistor for speed control, like the manufacture of Fantastic fans does, is that it wastes power. To reduce the current by half, you must use a resistor that is drawing as much power as the fan does. The PWM just turns the power on and off quickly. I suspect that the large capacitor smooths out the wave a bit. This wastes much less power. At the same fan speed you would be drawing far less current.

At $4 to $5, a PWM is cost competitive with a resistor.
David Tilston is offline   Reply With Quote
Old 06-16-2014, 11:50 AM   #14
Senior Member
 
Name: Drew
Trailer: Trillium Outback - 2004
Alberta
Posts: 106
Registry
Quote:
Originally Posted by David Tilston View Post
The only down side to using a resistor for speed control, like the manufacture of Fantastic fans does, is that it wastes power. To reduce the current by half, you must use a resistor that is drawing as much power as the fan does. The PWM just turns the power on and off quickly. I suspect that the large capacitor smooths out the wave a bit. This wastes much less power. At the same fan speed you would be drawing far less current.

At $4 to $5, a PWM is cost competitive with a resistor.
Perhaps I'm missing something? but my meter shows the fan drawing .72 amps when running through the resistor and 1.7 when it's not. The person who posted his mod in that link above also had similar results. Not saying you're wrong but it's not what I'm seeing through my Trimetric.
__________________
Where weíre going, we donít need a plug-in.
multi-task is offline   Reply With Quote
Old 06-16-2014, 12:27 PM   #15
Senior Member
 
David Tilston's Avatar
 
Name: Dave W
Trailer: Trillium 4500 - 1977, 1978 (2), 1300 - 1977, 1973, and a 1972
Alberta
Posts: 5,849
Registry
To get half the voltage at the fan, it is necessary to double the resistance in the circuit.

At full power the fan consumes 36 W, if you draw 3 A at full power, (W = V x I). This also means your fan is 4 ohms, (I=V/R, R=V/I, V=I x R). If you add another 4 ohms in series, the current is cut in half, to 1.5A. The voltage at the fan is now split between the resistor, and the fan, so 6 V each. The fan is consuming 9W, (W = V x I), and so is the resistor. 18 W total, or half the power consumption, but 1/4 the fan power. 9W wasted as heat.

The PWM wastes heat when it switches between full current, and no current. The higher the current flow, the more the waste heat. It will not make nearly as much heat as a resistor though.

And as for suggesting I am wrong, don't worry about it. I frequently am.
David Tilston is offline   Reply With Quote
Old 06-16-2014, 12:40 PM   #16
Senior Member
 
Name: Drew
Trailer: Trillium Outback - 2004
Alberta
Posts: 106
Registry
Quote:
Originally Posted by David Tilston View Post
To get half the voltage at the fan, it is necessary to double the resistance in the circuit.

At full power the fan consumes 36 W, if you draw 3 A at full power, (W = V x I). This also means your fan is 4 ohms, (I=V/R, R=V/I, V=I x R). If you add another 4 ohms in series, the current is cut in half, to 1.5A. The voltage at the fan is now split between the resistor, and the fan, so 6 V each. The fan is consuming 9W, (W = V x I), and so is the resistor. 18 W total, or half the power consumption, but 1/4 the fan power. 9W wasted as heat.

The PWM wastes heat when it switches between full current, and no current. The higher the current flow, the more the waste heat. It will not make nearly as much heat as a resistor though.

And as for suggesting I am wrong, don't worry about it. I frequently am.
Ok, perhaps I misunderstood. Just to confirm, both will reduce power consumption but one will lose more through heat and won't be as efficient?
__________________
Where weíre going, we donít need a plug-in.
multi-task is offline   Reply With Quote
Old 06-16-2014, 02:50 PM   #17
Senior Member
 
David Tilston's Avatar
 
Name: Dave W
Trailer: Trillium 4500 - 1977, 1978 (2), 1300 - 1977, 1973, and a 1972
Alberta
Posts: 5,849
Registry
Correct.
David Tilston is offline   Reply With Quote
Old 06-16-2014, 07:25 PM   #18
Senior Member
 
Night Sailor's Avatar
 
Name: Conrad
Trailer: Bigfoot 3000 & Barth "slide-in" truck camper
Connecticut
Posts: 958
I watched my current draw and had a few other things on--an inverter and some possibly some other small draws I did not disconnect the DC power and there are a few circuits hooked directly to the battery which were not included in my measurements.

I did not see a huge power savings, maybe half an amp at most on high. The best part was being able to dial it down low and quiet.

Right now I need the fan running because my puppy has a very serious eye infection and had surgery to open up two drains in her face. The infectious pus stinks despite all my efforts to keep her clean. The fan helps. I want to keep it from spreading to me it the other dog too.

In any event. I'm pleased with the results and hope it holds under prolonged use.
.
Night Sailor is offline   Reply With Quote
Old 06-17-2014, 09:43 AM   #19
Senior Member
 
David Tilston's Avatar
 
Name: Dave W
Trailer: Trillium 4500 - 1977, 1978 (2), 1300 - 1977, 1973, and a 1972
Alberta
Posts: 5,849
Registry
There should be no savings at full power. The PWM is basically off at that point. No pulses, just straight 12VDC. The power savings I am referring to only apply at lower speeds.
At 10% voltage to the fan, the resistor in the previous example would be ~36 ohms.

12V/40ohms = 0.3A
0.3A x 4 ohms (fan) = 1.2V
0.3A x 36 ohms (resistor) = 10.8V
0.3A x 1.2V (fan) = 0.36W
0.3A x 10.8V (resistor) = 3.24W

The worst case for power loss is actually my first example. 50/50 between the resistor, and fan. 9W would be about 0.75A at 12V.
David Tilston is offline   Reply With Quote
Old 06-18-2014, 12:21 AM   #20
Member
 
Name: Ron
Trailer: 2004 trillium outback 13ft
Alaska
Posts: 41
Registry
I just installed my pwm in my fan today. For some reason, when I turn it all the way down it still wants to turn the fan slightly, drawing current. So I wired it in after the factory switch so I could turn it off. Another thing I noticed is that the potentiometer does not seem to be linear. most of the adjustment happens in the first 45 deg of rotation. I may have a defective unit if it won't turn off.
__________________

Ak Ron is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Fan-Tastic Vent Speed Mod Patrick M. Modifications, Alterations and Updates 7 03-06-2008 12:40 AM
Speed Limits Bigfoot Mike General Chat 10 02-15-2008 04:12 PM
Two Dahon 6-speed Folding Bikes Steve & Terri Classified Archives 0 03-22-2007 09:43 AM
"Insane" 280 torque in little Mazda3 speed Frank G. General Chat 16 03-15-2007 05:54 AM
More Speed and More Fun Legacy Posts General Chat 4 05-31-2003 09:24 AM

» Upcoming Events
No events scheduled in
the next 465 days.
» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 11:16 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
×