| T O P I C R E V I E W |
| shawnselectronics@hotmail |
Posted - Sep 06 2006 : 03:31:08 AM
Im new here, dont let my name fool ya, Im vary limited on electrical knowledge but if I know what I needed I can assemble it.
Sorry, Ill try to keep this as short as possible.
I installed a P.W.M. controler to power my truck's cooling fan. It turns the fan into a variable speed fan instead of a relay style on/off fan. I want the fan to run after engine off but when I hook it up to do so once the voltage to the fan drops to about 2 volts or less the fan makes a high pitched noise and will continue as long as the controler sees temp signal and supplies voltage. If I can continue to power the controler for about 1-2 min after engine off then stop power to the controler, that would be just enough fan run time to cool the radiator and turn off the controler just before the voltage to the fan drops enough to cause the noise.
Id like to either:
Time the controler to run for 1-2 min after engine off.
Find some type of filter to filter the frequency type noise from the fan.
Or just eliminate the fan on after engine off feature and just use a manual fan on switch in the cab to use whenever I want.
But Im not sure which of my 3 ideas are easiest, if they can even be done and if so will they hurt the controler.
Here is a like to the site I bought the controler from, it is the FK-60
http://www.dccontrol.com/ Sorry you have to dig on this site to find stuff...right arrow to "fan selection", click on "hardware", next to any fan click on "accessories for this kit", scroll to bottom and click on "DC 35 / 60 data sheet" its an adobe page with specs on his products, the DC-60 is the same as my FK-60 and is pictured inthe 1st 3 diagrams. |
| 8 L A T E S T R E P L I E S (Newest First) |
| Aaron Cake |
Posted - Sep 14 2006 : 12:28:03 PM
quote:
Originally posted by shawnselectronics@hotmail
I really do appreciate the attempts to help me...maybe I didnt explain what I am trying to do.
I already have this controler box and it is working great except for it causes the fan to make a high pitched noise after the voltage to the fan drops down to 2 volts ot less and the noise continues for 30-45 min. Im trying to find a way to cure the noise and still have fan operation after the engine is off. Further below describes more details. directly below describes my ideas and answers from you guys.
OK. The noise is created by the resonance of the motor's windings. There is no way to avoid it and still use PWM.
The voltage of "2 volts" you are measuring is not actually correct. Your meter is very confused by the PWM. Really you should be measuring 12V. You are seeing 2V because that is the average created by the PWM chopping.
quote:
My response: I already have the controler box to do this, I just need a way to turn off power to it after a set amount of time.
If this box has an "override" input, then you can make a simple timer circuit to allow it to run after the engine has stopped.
However if your problem is that the fan continues to run after you have keyed off the engine, then you need to connect it's power supply to IGN switched power, and not a direct 12V source.
quote:
My response: My fan does run at 2 volts but makes a high pitched noise. The fan does stop turning at about 1 volt but the noise from the fan continues untill the controler box stops suppling voltage(which can sometimes take 30-45 min, thats why I want to time power to it) My Fluke meter shows voltage coming from the controler to the fan ranging from 0v to 9v depending on fan speed and will supply more as temp raises it just doesnt get hot enough to do so.
See above regarding PWM.
quote:
My response: OK, but my truck did not come with an e-fan, I replaced my mechanical fan with it. By looking at the specs on that website I listed on my 1st post, can you tell if doing an overide switch/relay will backfeed to the control box and damage it?
Neither did mine.
I honestly don't know if bypassing the box will be a problem. I would hope that the outputs have been properly protected but who knows. Best contact the company.
quote:
I think the simplest way to fix the noise problem would be a filter of some kind but I dont know what to get or where to get it or where to install it
Wouldn't work.
quote:
I dont want to offend anyone here or get into a big debate about anything but...while the t-stat does regulate engine temp, it is just 1 part, the fan regulates temp too and in more ways than 1 depending on the type of fan setup.
With an e-fan the t-stat controls coolant flow and the fan controls coolant temp by cycling on/off within a certain temp range window.
With a mechanical fan and fan clutch the t-stat controls coolant flow and the fan regulates coolant temp by means of engine rpm and clutch engage/disengage making this a crude version of the "variable speed fan" and making the temp range window smaller.
There is no debate at all. The engine's temp is controlled by the thermostat. The fan's only job is to provide air through the rad to cool the coolant. The thermostat on the fan simply tells it to come on only when required and has no bearing on the temperature of the engine (unless it is set stupidly high preventing the necessary airflow through the rad).
quote:
Once warmed up, my truck runs within a 2-3 degree temp range window no matter where Im driving of what kind of driving Im doing.
That would be the thermostat doing it's job.
quote:
That precice of temp control is not needed, I just thought it was a pretty cool product and wanted to try it on my truck.
To me, it sounds like WAY too much effort to go through. |
| shawnselectronics@hotmail |
Posted - Sep 13 2006 : 8:24:29 PM
I really do appreciate the attempts to help me...maybe I didnt explain what I am trying to do.
I already have this controler box and it is working great except for it causes the fan to make a high pitched noise after the voltage to the fan drops down to 2 volts ot less and the noise continues for 30-45 min. Im trying to find a way to cure the noise and still have fan operation after the engine is off. Further below describes more details. directly below describes my ideas and answers from you guys.
My idea: 1) A way to time it to shut off 30sec/1min/2min after engine off?
You replied: OK, if you want to make a circuit, then it isn't too hard. You need a temperature probe made from something like a thermistor or a standard (GM style probably because it's cheap and known) automotive temp sensor screwed into the rad. A microcontroller will read the voltage from the temp sensor via it's ADC and then do a little calculation and decide on a fan speed. Most microcontrollers have PWM outputs so it's likely you can output directly to a few big MOSFETs to control the fan. Then any features you want to add are just a added to software...Still seems like way too much trouble for me considering there's no gain...
My response: I already have the controler box to do this, I just need a way to turn off power to it after a set amount of time.
My idea: 2) A way to filter the noise the fan makes at low voltages (2 volts or less)
You replied: The fan won't run at 2V, so it's not an issue. With PWM, the fan will always be seeing a full 12V anyway.
My response: My fan does run at 2 volts but makes a high pitched noise. The fan does stop turning at about 1 volt but the noise from the fan continues untill the controler box stops suppling voltage(which can sometimes take 30-45 min, thats why I want to time power to it) My Fluke meter shows voltage coming from the controler to the fan ranging from 0v to 9v depending on fan speed and will supply more as temp raises it just doesnt get hot enough to do so.
My idea: 3) Or just eliminate the fan on after engine off feature and just use a manual "fan on" switch(and relay) to use at the track to cool the radiator after runs. As it is now the controler runs the fan automaticly to do this but for street use the fan runs too long and at lower volatages (2 and under) the fan is noisy.
You replied: That's exactly what I do at the track. My fan is controlled automatically by the ECU but I have a bypass switch for the pits to help with heat soak.
My response: OK, but my truck did not come with an e-fan, I replaced my mechanical fan with it. By looking at the specs on that website I listed on my 1st post, can you tell if doing an overide switch/relay will backfeed to the control box and damage it?
I think the simplest way to fix the noise problem would be a filter of some kind but I dont know what to get or where to get it or where to install it
I dont want to offend anyone here or get into a big debate about anything but...while the t-stat does regulate engine temp, it is just 1 part, the fan regulates temp too and in more ways than 1 depending on the type of fan setup.
With an e-fan the t-stat controls coolant flow and the fan controls coolant temp by cycling on/off within a certain temp range window.
With a mechanical fan and fan clutch the t-stat controls coolant flow and the fan regulates coolant temp by means of engine rpm and clutch engage/disengage making this a crude version of the "variable speed fan" and making the temp range window smaller.
With an e-fan and this controler box I have, these same things apply but the e-fan speed is varied from 0 rpms to max rpms and anything in between and makes the temp range window vary small. Once warmed up, my truck runs within a 2-3 degree temp range window no matter where Im driving of what kind of driving Im doing. That precice of temp control is not needed, I just thought it was a pretty cool product and wanted to try it on my truck. |
| Aaron Cake |
Posted - Sep 11 2006 : 09:42:49 AM
quote:
Originally posted by shawnselectronics@hotmail
Ive ben an automotive tech for 15 yrs and installed lots of e-fans too. The last few Ive installed have used the controler instead of realy, I liked them so I thought Id try 1 on my own truck. The variable speed of the fan actually keeps the temp constant instead of fluctuating up and down as the fan cycles on/off.
An automotive tech should know that the thermostat is what regulates engine temperature, not the fan. 
quote:
1) A way to time it to shut off 30sec/1min/2min after engine off?
OK, if you want to make a circuit, then it isn't too hard. You need a temperature probe made from something like a thermistor or a standard (GM style probably because it's cheap and known) automotive temp sensor screwed into the rad. A microcontroller will read the voltage from the temp sensor via it's ADC and then do a little calculation and decide on a fan speed. Most microcontrollers have PWM outputs so it's likely you can output directly to a few big MOSFETs to control the fan. Then any features you want to add are just a added to software...Still seems like way too much trouble for me considering there's no gain...
quote:
2) A way to filter the noise the fan makes at low voltages (2 volts or less)
The fan won't run at 2V, so it's not an issue. With PWM, the fan will always be seeing a full 12V anyway.
quote:
3) Or just eliminate the fan on after engine off feature and just use a manual "fan on" switch(and relay) to use at the track to cool the radiator after runs. As it is now the controler runs the fan automaticly to do this but for street use the fan runs too long and at lower volatages (2 and under) the fan is noisy.
That's exactly what I do at the track. My fan is controlled automatically by the ECU but I have a bypass switch for the pits to help with heat soak. |
| shawnselectronics@hotmail |
Posted - Sep 10 2006 : 12:51:20 PM
Ive ben an automotive tech for 15 yrs and installed lots of e-fans too. The last few Ive installed have used the controler instead of realy, I liked them so I thought Id try 1 on my own truck. The variable speed of the fan actually keeps the temp constant instead of fluctuating up and down as the fan cycles on/off. There os more about it on that website.
I just need to know if anyone can look at the specs and tell me if there is:
1) A way to time it to shut off 30sec/1min/2min after engine off?
2) A way to filter the noise the fan makes at low voltages (2 volts or less)
3) Or just eliminate the fan on after engine off feature and just use a manual "fan on" switch(and relay) to use at the track to cool the radiator after runs. As it is now the controler runs the fan automaticly to do this but for street use the fan runs too long and at lower volatages (2 and under) the fan is noisy. |
| Aaron Cake |
Posted - Sep 10 2006 : 10:15:11 AM
Why would you need fan speeds less then 50%?
Honestly I run every fan I install at either off or 100%, so I don't see the need for adjustable speeds in any way.
Another option for the electronics limited would be to purchase a surplus electric scooter controller. These are often found on eBay for a few dollars and can easily handle the current required. The input expects a pot to adjust the speed but you could rig up a few relays and resistorsto give you several speeds. Or find a thermister of appropriate value and make it automatic. |
| Schleusner |
Posted - Sep 09 2006 : 11:39:06 AM
Bigger is not allways better. |
| shawnselectronics@hotmail |
Posted - Sep 08 2006 : 02:17:51 AM
I actually chose this 1 over the Spal because this 1 supplies power to the fan from 0-100% as needed where as the Spal supplies power to the fan from 50-100%(starting at 50%) at least the few Ive seen installed did and the specs say so too. And the Spal is a much bigger in size. |
| Aaron Cake |
Posted - Sep 07 2006 : 11:32:40 AM
Spal makes a fan controller that does exactly what you need. |
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