Topic: Flex A Lite

[mrcabinet]

I finally got around to installing the flex a lite 485 fan that I've had sitting around for awhile. So far I really like it. My only complaint is that it might actually cool too well and makes the fan cycle on and off more than I'd like. Is it possible to put an inexpensive rheostat on the power line going to the fan from the controller - one that I could use to slow the fan speed down? During the summer I might want to turn it up to full speed again.The mfg. has a variable speed switch, but I really don't feel like (or have the funds) to spend $107 on it.

[Jeffy]

Can't you turn the dial up on the controller?

[dwtaylorpdx]

There are two controllers, the cheap thermostats and the more expensive thermostat+speed control versions....

Dave

[Jeffy]

There are two controllers, the cheap thermostats and the more expensive thermostat+speed control versions....

Dave

His fan should have a controller on it.

[mrcabinet]

It does have a controller, and it keeps it right at 210. I just don't like the frequency with which it cycles on and off. I would prefer to slow down the speed and have it cycle less without having to spend the bucks for a variable speed controller.

[Jeffy]

It does have a controller, and it keeps it right at 210. I just don't like the frequency with which it cycles on and off. I would prefer to slow down the speed and have it cycle less without having to spend the bucks for a variable speed controller.

So why not adjust it?


*See Step 10 - http://www.flex-a-lite.com/auto/485-99485.pdf

Specifications

Part #485 Puller
Mounting Surface Required 21 1/2" x 17 1/2" x 4 3/16"
Fan Assembly Diameter 16"
Fan RPM @13.5VDC 2450
Number of Blades/Fan Blade Angle 8/variable
Airflow-Cu. Ft./Min. at 0º Static Pressure 3300
Amp Draw 18
Mounting System Custom Brackets
Adj. Thermostat 160º-240º Yes
Air Conditioning Relay Yes

[mrcabinet]

I don't want to adjust the temperature - just the fan speed. I found an old-school 30 amp fan motor rheostat at a local restoration shop that should do the trick.

[Mozman68]

But by adjusting the temperature higher it shouldn't go on for very long or at all dependin on how hot it gets.

I don't understand why this would be worse than having it go on at a lower speed and stayin on for a longer time period like you will be makIng it do?

Mine goes on at low speed around 185...jumps to high speed at 195 if it needs to....

[Jeffy]

But by adjusting the temperature higher it shouldn't go on for very long or at all dependin on how hot it gets.

I don't understand why this would be worse than having it go on at a lower speed and stayin on for a longer time period like you will be makIng it do?

Mine goes on at low speed around 185...jumps to high speed at 195 if it needs to....

That's typically how you adjust the intervals. It sounds like he has his fan set too low so it's turning on too early then shutting off then turning on again.  Once the engine is up to temp, the fan shouldn't be turning on immediately.  I have mine set at 185 at the probe (which means it's hotter in the engine) so the fan turns on if I sit idle for more then several seconds.  It turns off once I start moving though and doesn't turn on again until I stop.

From a performance stand point, it defeats the purpose of going electric if you're going to run the fan longer or if your fan is set too low so it's turning on and off a lot.  Once you're moving, the fan shouldn't be on unless it's really hot outside.  Also there are no free lunches when it comes to electricity.  The potentiometer works by increasing the resistance.  This in turn increases the amps on that circuit. (E=I/R)  So you have to make sure your components, wires and especially connectors can handle the increase in amps.  Flex-a-lite parts are pretty low amp stuff.

[sharpxmen]

Also there are no free lunches when it comes to electricity.  The potentiometer works by increasing the resistance.  This in turn increases the amps on that circuit. (E=I/R)  So you have to make sure your components, wires and especially connectors can handle the increase in amps.  Flex-a-lite parts are pretty low amp stuff.

actually is the other way around, higher resistivity means less amps

U=I*R or I(amps)=U(volts)/R(ohm)


so with a resistor in series would lower the amps, although you have losses due to heat dissipation.

If you put the resistor in parallel then you increase the amps but that means a lower total resistivity and it won't lower the speed of the fan.

[Jeffy]

actually is the other way around, higher resistivity means less amps

U=I*R or I(amps)=U(volts)/R(ohm)


so with a resistor in series would lower the amps, although you have losses due to heat dissipation.

If you put the resistor in parallel then you increase the amps but that means a lower total resistivity and it won't lower the speed of the fan.

Whoops, should have paid more attention to what I was writing.  You're right.  I knew someone would catch me on it if I was incorrect too.