Date: Thu, 20 Apr 2017 22:39:10 -0700
Reply-To: Alistair Bell <albell@SHAW.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Alistair Bell <albell@SHAW.CA>
Subject: Re: variable speed blower fan
In-Reply-To: <CAFdLW6km7c7SdaVhhSuZ=3sfvnEk6ihfhLQAae6GW7Uq+_shtA@mail.gmail.com>
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As I said, I've been playing with a couple of PWM controllers and a spare fan. The fan is in good shape and as well as using it to experiment with the controllers I've been seeing just how added oil to the exposed bushing would work. You know, the mullendore port thing. David B has said before, and I agree, that the only real way of getting a good amount of oil into that bushing is to disassemble the motor and soak the bushing ( sintered bronze?) in warm oil. I think he even mentioned reduced pressure to get the oil into the matrix of the bushing.
Anyhoo, I've added oil to the bushing with the fan sitting on end so the oil would pool on shaft and bushing and I did notice the oil disappearing. It's going somewhere, and maybe some of it is going into the bushing.
The PWM controllers I've been using are on exposed circuit boards, not in a nice box like the one you referenced. There are heat sinks on the board and the heat sinks do get warm in use. I do not know if the heat is an issue if the controller is installed in the dash.
The frequency listed for your controller is I think 25kHz, and that's good, beyond our hearing range. My controllers are 15 and 20 kHz. I've wondered if there would be any noise issues but I can't hear anything with the units in the bench.
My controllers have similar remote potentiometers. I have tried to installed the pots in a spare stock switch plate, slightly modified for the pot leads. But the shaft of the pot is just a tad to short, the switch plate needs to be thinned out a couple of millimetres. So I can't say if the pot in your choice will be an easy install on the switch plate if that's what you are thinkjg of doing.
The speed control is impressive. From quite slow to full blast. But that might be a mixed blessing. The three speed stock set up is much easier to use in real life, you don't have to fiddle with a position.
I think there needs to be some sort of speed indicator. Maybe a variable brightness led ?
All in all I found it worth while to experiment with the controllers. As a back up in case of resistor failure. If that was the cause of the fan not working, adding the PWM controller seems like easier chore than pulling the dash. Ditto if failure due to stock switch.
Electrical connections? The controller has power in, plus&minus, and power out, plus&minus. At the stock switch I think it's black/yellow wire that supplies 12 volts and the yellow wire is the positive feed to the fan motor , that is the direct, no resistor feed. But check that with Bentley for your van, I'm going on hazy memory.
The ground is common. You know, I just realized I haven't tried my controller with common ground. I'm leading the plus and minus from the bench mounted fan motor straight to the controller, the plus and minus inputs are coming from a bench top power supply. I'll check that out to make sure nothing weird happens. Yeah, I'm thinking that I need to figure that out stat.
Otherwise you have to dig for the fan motor ground wire and I can't recall where that ends up in the harness.
Maybe I'm over thinking that. I know that this mod has been done many times. Hold on, I think the 80-90 wiki has an entry...nope, heading but no entry. But here's a YouTube vid about it
https://www.youtube.com/watch?v=3GzJ8N1Rqp8&t=19s
Yeah he has the motor ground wire to the controller, not common with the input neg feed. Now I'm really keen to see what happens with common ground. Maybe I can let some magic smoke out of one of my controllers :-).
Hope this helps a little more than it confuses.
Alistair
> On Apr 20, 2017, at 8:47 PM, Dan N <dn92610@gmail.com> wrote:
>
> thank you Alistair...
>
> bon appétit...
>
> please... more info on what you have and how to wire it...
>
> dan