TPS & temperature

3 replies to this topic
• John221ex

Posted February 12, 2007 - 06:07 AM

After searching the posts and finding no answer, I would like to know if anyone has an idea how temperature affects the resistance values given in the manual for the TPS.
We don't all live in perfect California, and here on the right coast, my garage is a balmy 35 degrees under the reference temperature.

John

• Indy_WR450

Posted February 12, 2007 - 12:35 PM

Wire Gauge Resistance per foot of wire @ 70 degrees F:

10 Gauge 0.00118
12 Gauge 0.00187
14 Gauge 0.00297
16 Gauge 0.00473
18 Gauge 0.00751
20 Gauge 0.0119
22 Gauge 0.0190
24 Gauge 0.0302
26 Gauge 0.0480
28 Gauge 0.0764

Copper wire has a resistivity coefficient of 0.0039 per degree C or 0.00216 per degree F.
So the resistance change is calculated by the measured resistance at a specific temperature with respect to the observed temperature:

The new reisitance at temp T is calculated with the following simple formula where R is the measured or calculated resistance by feet of wire and gauge at 70 degrees:

[COLOR="Navy"]R (at T) = R (at 70F) x ( 1 + 0.00216 x (T - 70F)[/COLOR]

Therefore a 50 degree temperature swing from room temperature will change the copper wire resistance by 10.8 percent higher ( if riding in 120F desert) or lower ( if riding in freezing 0F Alaska)

Hope that helps.

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• John221ex

Posted February 12, 2007 - 01:29 PM

I knew there would be someone with a technical mind to help!

So, in essence, about 5% difference (lower in resistance) for about thirty degrees under the spec temperature? Or, a negligible effect?

John

• Indy_WR450

Posted February 12, 2007 - 05:10 PM

You got it John! About 6% change for 30 degrees.