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View Full Version : What do you know about thermoswitches?



PhillyDRFT
04-06-2007, 04:07 AM
http://nissaninfiniticlub.net/photopost/data/500/13306IMG_8070.JPG

I got this universal thermoswitch for my duel electric fans. Since it uses an external probe that goes outside of the fins (causing a delay I don't like). Could I snip off the probe and solder it upto a temp sender like gauges use? or are they different systems? I'm pretty new to electrical so I only know basics.

Thanks in advance guys.

grayscale
04-06-2007, 04:52 AM
I don't believe so. I think the temp sensing probe is like a thermometer. I'm not familiar with how, but the bulb end reads the temp mechanically(for lack of a better term) in the same sense that mercury does. It's not just an electrical thing which is why I say I don't believe so, but I'm not real sure. You don't have a factory radiator temp sender you can use? What do you mean by delay?

PhillyDRFT
04-06-2007, 05:19 AM
I don't believe so. I think the temp sensing probe is like a thermometer. I'm not familiar with how, but the bulb end reads the temp mechanically(for lack of a better term) in the same sense that mercury does. It's not just an electrical thing which is why I say I don't believe so, but I'm not real sure. You don't have a factory radiator temp sender you can use? What do you mean by delay?

I have a Sender and a Sensor on my intake manifold. There isn't a bubble at the end it's pressed flat. I thought the same thing of it being a mercury switch but I don't imagine them being adjustable since the wire inside would have to be a certan legnth from the well of mercury inside the thermometer. Since both the sender and the probe work on one wire I figured It's not too far fetched.

Edit: and by delay I mean since my fans are there to cool my water temp through the radiator I would like a direct signal of water temp as opposed to ambient heat from the radiator.

grayscale
04-06-2007, 01:38 PM
Here is what I could find. The type of probe you are using is known as bulb an capillary. The bulb being the bulb, and the capillary is the lead between the bulb and switch.

Theory of Operation
Bulb and capillary controls are designed to open or close electrical circuits in response to changes in temperature. These devices use a vapor pressure technology to sense changes in temperature. The pressure change is transmitted to the bellows through a bulb and capillary tube. Pressure in the system changes in proportion to the temperature of the bulb. The bellows, bulb, and capillary are filled with a temperature-responsive liquid. The vapor pressure of the liquid increases as the temperature of the bulb increases. System temperature is converted to pressure through the bulb and capillary, which are connected to the control at the mounting stem. Pressure applied to the actuator changes in proportion to the temperature of the bulb. As temperature rises, the bellows exerts force on the main spring. When the threshold force of the main spring is overcome, it transfers the motion to the contact block and actuates the contacts — this is referred to as the Trip Setting. As temperature decreases, the main spring will retract. When the threshold force on the differential blade spring is overcome, the contacts will return to their normal state —this is referred to as Reset Setting. Varying the force of the main spring (by turning the operating range adjustment screw) determines when the contacts will trip. Varying the force on the secondary differential blade spring (by turning the differential adjustment screw) determines when the contacts will reset. Setting trip and reset determines control operation.

alltracman78
04-06-2007, 02:19 PM
You need to get some kind of a sender that can be inserted into your rad then.
Doesn't your stock system use some type of switch to turn the stock fans on?
Why can't you reuse that?

That isn't able to be cut and attached to something else.
Neither would the senders/sensors in your engine.

PhillyDRFT
04-06-2007, 04:00 PM
You need to get some kind of a sender that can be inserted into your rad then.
Doesn't your stock system use some type of switch to turn the stock fans on?
Why can't you reuse that?

That isn't able to be cut and attached to something else.
Neither would the senders/sensors in your engine.

nope 240's use a clutch fan driven by the water pump pulley. The only electric fan is a backup for the AC system. I'll just use it the way it's ment to untill I can afford the 110$ DIF duel fan controller. It runs off the water temp sensor. This is just a temp fix for a number of reasons. 240s have plastic radiator end tanks which tend to break after so many miles, so after replacing it with a koyo that has metal end tanks I find my fan shrouds all broke dick. and the parts manufacturer sent me an automatic trans radiator so it has two extra coolent outputs at the bottom end tank, so my lower fan shroud doesn't fit over them. So the common option is dual Altima fans. So I'll grab a pair at my junk yard for 10$. new shrouds are like 60$ each from the dealer and there pretty pricey on the forum. Not to mention i'll take any excuse to get the clutch fan out so I don't sound like a mac truck anymore. Thanks for the help guys.

Where did you find all of that greyscale? Very informative. It didn't look like a sealed unit to me so I wasnt sure if the internal workings of it were the same as a sender.

Edit: also thanks again to everyone sorry if I ask stuff for my nissan here. It's just that 9 times out of 10 I get better info here than Nico. Theres only about 4 people who post in the turbo forum who really know what there talking about.

grayscale
04-07-2007, 04:01 AM
I googled it. Most of the good info I read came from various places on the AllenBradley site.

That's funny cause I used dual Altima fans several years ago in my '78 Celica along with the Altima radiator.

PhillyDRFT
04-07-2007, 05:42 AM
I googled it. Most of the good info I read came from various places on the AllenBradley site.

That's funny cause I used dual Altima fans several years ago in my '78 Celica along with the Altima radiator.

Haha there such a nice piece. being two duel speed 14" fans. It's hard to pass up as a 20$ junk yard find!