Is this normal?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

fuelpump · 01-18-2008, 09:04 AM

I'm rewiring the heater on my 60 and decided to test the system before mounting the resistor and blower speed switch. The blower has three speeds but on the middle speed the small wire side of the resistor really glows red as you can see from the picture. Is this normal???

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Name: IMG_1498.JPG
Views: 152
Size: 44.3 KB

joe231 · 01-18-2008, 09:10 AM

I believe that is why they mount it inside the air duct to cool it down. A resistor by design removes unwanted energy by converting it to heat and dissipating it, not sure about the glow, but know that they do get very hot.

budden · 01-18-2008, 10:20 AM

very normal

greg64 · 01-18-2008, 10:50 AM

I doubt it would be red hot if mounted inside the airflow. Quite clever really, because it's a free cooling system, plus there's no way the fan can give out (no cooling) and still have a load through the resistor (fail safe).

Fred T · 01-19-2008, 07:29 AM

All resistors produce heat when current flows through them. I used to know which law of thermodynamics that involved, but I've had a beer since then.

fuelpump · 01-19-2008, 08:39 AM

Thanks for the comments guys. I was aware of the basic theory at work here but I just didn't know the wire (out of the air flow) would get THAT hot.

PrerunnerRob · 01-19-2008, 12:01 PM

Quote:

Originally Posted by fuelpump

Thanks for the comments guys. I was aware of the basic theory at work here but I just didn't know the wire (out of the air flow) would get THAT hot.

If you want a practical example, take a hair dryer, put it on high and look at the how hot everything glows, then put your hand(or something else) over the air intake. It will glow waaay more then it did before!

01-18-2008, 09:04 AM	#1
fuelpump Registered User Join Date: Sep 2007 Location: caro, mi Posts: 171	Is this normal?? I'm rewiring the heater on my 60 and decided to test the system before mounting the resistor and blower speed switch. The blower has three speeds but on the middle speed the small wire side of the resistor really glows red as you can see from the picture. Is this normal???

01-18-2008, 09:10 AM	#2
joe231 Registered User Join Date: Dec 2007 Location: Palmer, Alaska Posts: 13,821	Re: Is this normal?? I believe that is why they mount it inside the air duct to cool it down. A resistor by design removes unwanted energy by converting it to heat and dissipating it, not sure about the glow, but know that they do get very hot.

01-18-2008, 10:20 AM	#3
budden Registered User Join Date: Jul 2007 Location: kimberly idaho Posts: 24	Re: Is this normal?? very normal

01-18-2008, 10:50 AM	#4
greg64 Registered User Join Date: Dec 2007 Location: Kimberley, BC, Canada Posts: 799	Re: Is this normal?? I doubt it would be red hot if mounted inside the airflow. Quite clever really, because it's a free cooling system, plus there's no way the fan can give out (no cooling) and still have a load through the resistor (fail safe). __________________ Greg 64 GMC Suburban - 283, NV3500, 14 bolt 77 C10 swb - 292, SM465, 12 bolt

01-19-2008, 07:29 AM	#5
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	Re: Is this normal?? All resistors produce heat when current flows through them. I used to know which law of thermodynamics that involved, but I've had a beer since then. __________________ Fred There is no such thing as too much cam...just not enough engine.

01-19-2008, 08:39 AM	#6
fuelpump Registered User Join Date: Sep 2007 Location: caro, mi Posts: 171	Re: Is this normal?? Thanks for the comments guys. I was aware of the basic theory at work here but I just didn't know the wire (out of the air flow) would get THAT hot.



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