Thread: Custom PCB
View Single Post
  #9   Spotlight this post!  
Unread 06-01-2002, 21:37
Allen Smith Allen Smith is offline
Registered User
no team
 
Join Date: May 2001
Location: Milton, MA
Posts: 6
Allen Smith is an unknown quantity at this point
Send a message via AIM to Allen Smith Send a message via Yahoo to Allen Smith
Is section 2 online?

Did you find this section online? If you did, where is it?
For a current sensor one method is to use a low-ohm shunt to convert the current flowing thru the shunt to a voltage that could be measured. 10 gauge wire has about 1 ohm/1000 ft so you could use say 10 ft of 10 ga. wire with a "sense" wire at each end of the 10ft shunt. If we want to measure currents in the 20 to 60 Amp range...
V=I*R (voltage=current*resistance)
V=20 Amps*.001 ohms (1ohm/1000ft*10ft)
V=.2 volts for 20 Amps to .6 volts for 60 Amps would be our signal. That sounds like it is big enough to do something with. But how much power would be lost in the 10 extra feet of wire?
W=I^2*R (Watts=current squared*resistance)
W=60^2*.001 60 amps worst case
W=3.6 Watts, I can live with that.
Now what to do with the signal? How do you get the info back to the driver?
__________________
Allen Smith
check out http://www.gadgeteer.org
An Etch-A-Sketch you control over the web