What is Milliohms Typical? Cable assemblies for vehicles

[pancho]

Can anyone here help enlighten me as to what exactly Milliohms Typical is? What exactly is someone measuring when using this formula?

[Jim Wynne]

Originally Posted by pancho

Can anyone here help enlighten me as to what exactly Milliohms Typical is? What exactly is someone measuring when using this formula?

You'll need to supply some context. In general, when "typical" is used in a specification it means that the callout applies generally to like features other than the one the specification is actually linked to. In the case of a mechanical drawing, if a plate were depicted with three holes in it and a specification next to one of the holes that says "x.xx dia. typical" it means that the spec also applies to other holes that aren't individually specified. But we can't guess what your "typical" might mean without more information.

[pancho]

sorry my bad for the lack of information I supplied. We manufacture cable assemblies for vehicles and while I have the formula for figuring out milliohms typical, I just would like to know what exactly these numbers mean for resistance of the raw cable. I'm assuming that in most resistance applications the higher the resistance the more loss your getting, of course depending on length, manufacturer, etc. But what exactly am I trying to measure when asked to milliohms typical?

[Jim Wynne]

Originally Posted by pancho

sorry my bad for the lack of information I supplied. We manufacture cable assemblies for vehicles and while I have the formula for figuring out milliohms typical, I just would like to know what exactly these numbers mean for resistance of the raw cable. I'm assuming that in most resistance applications the higher the resistance the more loss your getting, of course depending on length, manufacturer, etc. But what exactly am I trying to measure when asked to milliohms typical?

I think what you're referring to might be a manufacturer's specification that can't be precise or guaranteed due to the fact that the manufacturer can't anticipate the application, and resistance (or impedance, especially) might vary depending on the application.

[Al Rosen]

Originally Posted by pancho

sorry my bad for the lack of information I supplied. We manufacture cable assemblies for vehicles and while I have the formula for figuring out milliohms typical, I just would like to know what exactly these numbers mean for resistance of the raw cable. I'm assuming that in most resistance applications the higher the resistance the more loss your getting, of course depending on length, manufacturer, etc. But what exactly am I trying to measure when asked to milliohms typical?

The opposition to the flow of current is resistance, which is measured in Ohms. If you have 1 volt of electric potential(E) that produces 1 Amp of electric current(I), you have 1 ohm of resistance(R). Resistance is directly proportional to the voltage and inversely proportional to the current or stated another way:

R(ohms)=E(volts)/I(amps)

1 milliohm = 0.001 ohms

This answers the question of what you are measuring. Now it is true the higher the resistance the more loss you are getting. The loss is expressed as:

I^2*R=P (watts)

For the raw cable the resistance is proportional to length (L) of the cable and inversly proportional to the cross sectional area(A):

R=k*L/A
k=constant for the material usually expressed as the greek letter rho.

[ralphsulser]

Impressive Mr. Rosen You really do know this stuff

[Al Rosen]

Originally Posted by ralphsulser

Impressive Mr. Rosen You really do know this stuff

Physics 101