time delay switch for radiator aux fan

[voltscastillo]

planning to add an aux electric fan for an old car. first time i'll be doing this.

gusto ko sana malaman kung may switch na mag control sa aux fan na ito, yung parang sa mga bagong kotse ngayon na nag aactivate lang yung fan every 30 seconds or so (hindi parating naka-on) para hindi naman masunog yung fan motor prematurely.

gusto ko sana may controllable switch mounted sa dash, tapos selectable: low (1 cycle per minute), medium (1 cycle per 30 seconds), and high (on all the time). hindi naman kasi maganda yung sobra sobrang cooling... pag maulan or malamig set ko lang sa less cycles...

what do you call this type of switch (if any exist)? cost? alam ko kasi sa aux fans pag on mo ng switch nun derecho on na yun eh.

thanks for any help.

[oj88]

What you want can be done using the 555 timer in astable mode. Play around with R1, R2 and C to achieve the desired duty cycle (how much time the fan is ON) and delay (how much time the fan is OFF). You should use a relay for this circuit to operate the fan.

Of course, the more elegant solution is to use a thermoswitch that will turn the fan on and off as needed.

[CVT]

^^^ Ang walang kamatayang 555 timer....

7909:taunt:

[jick.cejoco]

planning to add an aux electric fan for an old car. first time i'll be doing this.

gusto ko sana malaman kung may switch na mag control sa aux fan na ito, yung parang sa mga bagong kotse ngayon na nag aactivate lang yung fan every 30 seconds or so (hindi parating naka-on) para hindi naman masunog yung fan motor prematurely.

gusto ko sana may controllable switch mounted sa dash, tapos selectable: low (1 cycle per minute), medium (1 cycle per 30 seconds), and high (on all the time). hindi naman kasi maganda yung sobra sobrang cooling... pag maulan or malamig set ko lang sa less cycles...

what do you call this type of switch (if any exist)? cost? alam ko kasi sa aux fans pag on mo ng switch nun derecho on na yun eh.

thanks for any help.

volts,
for hour car to run at optimum efficiency and to minimize pollution, our car has to operate at a range between 190 to 240 degrees or at a target of 215 degrees fahrenheit. keep the pressure in the cooling system to 15 psi. for each 1 psi rise in pressure in your pressurized cooling system, an average of 3 degrees rise in boiling point results. the radiator cap keeps the pressure in the system as would the pressure cooker you have in your kitchen. the antifreeze/coolant solution raises the boiling point and lowers the freezing point of the coolant liquid. to convert your old car to electric cooling fan from the traditional belt driven fan improves expected gas mileage that the engine is not pulling an extra fan load and maintains a narrow band of temperature, the ideal one. to convert your fan system, you do not need to experiment and waste time and money by matching you engine displacement to a newer car and use the newer car's fan size and capacity. you can buy this aftermarket. you will need a 30 ampere N.O. (normally open relay or make type relay) and a fan thermoswitch that you can install at the inlet side of your thermostat housing by tapping a thread big enough for your thermoswitch. the rest is wiring. better still use aftermarket parts that you can buy from jcwhitney or check the internet. they are pretty mch universal.
jick
ase certified master automobile technician
ase certified master heavy duty truck technician
international automotive technician's network

[voltscastillo]

thanks gents

it's a 79 galant with the saturn/astron engine, btw.

me and a buddy of mine tryng to restore it in our free time. we're just about done with the paint, and the engine, now's time for the cooling system and electronics. thankfully, cars of this generation have almost none, apart from the lights and radio, hehehe.

*oj888

yes the thermoswitch system is the cleaner solution. is there a non-oem thermoswitch available sa auto supply stores? if so, does it come equipped with a probe that can be inserted into the thermostat housing (or near it?) or just tapped into the radiator somewhere?

*jick.cejoco

i'm more inclined to rig up this switch ghetto style. but since the thermoswitch alternative seems more reliable, yes i would give it a try. but the car has not used a working, oem thermostat in about a decade, and we forgot about making a provision for a thermoswitch when the tech was putting it all back together after the rebuild.

[oj88]

Volts,

I highly recommend that you read the following article: http://www.aaroncake.net/rx-7/efaninstall.htm

Despite my earlier post, I would suggest that you go for the proper method of installing a radiator fan; which is to automatically turn it on and off using an electric thermostat or thermoswitch. Manual switching, as you'll find out in the article, can be too cumbersome for the driver and inefficient.

[alwayz_yummy]

why not just install a thermo-switch, where in the fan will bill turned on if the temp reaches the preset value and turns off at a preset value also.

dami pa nyung wiring -wiring, thermo switch ay tatap lang between then tapos na...

[oj88]

why not just install a thermo-switch, where in the fan will bill turned on if the temp reaches the preset value and turns off at a preset value also.

dami pa nyung wiring -wiring, thermo switch ay tatap lang between then tapos na...

You're making it too simplistic. You need to have fuses, a relay and a properly calibrated thermostat/switch that will operate the fan at the correct engine temp. Then there's the issue of where to put it (ie. top or bottom of the radiator, before or after the thermostat valve, water inlet or outlet, etc.)

Solutions to seemingly simple problems should still follow best practices.