bufordtpisser
New Member
Re: Another electrical question...
That was my mistake. What I should have said was that if you do not know if there is an internal shunt, wire one in and then test the guage with a meter to see if the reading is correct. The use of the dropping resister is after the guage, and therefore will not have an effect on the reading. As far as 60 amps not being an issue in a DC circuit, I have had readings many time that amount on DC circuits. And even though the wire were very hot at the time, other components failed long before the guage crapped out. I have also seen severe damage in circuits where the current drawing device was shutdown suddenly and backfeed current literally melted components. Did you ever wonder why most circuits on a vehicle had 20 to 30 amp fuses on wires as small as 14 guage?? The resister that I was suggesting was merely to stop back feed. The proper way to do amperage measurement is to use a meter that is not a part of the circuit. Either using a clamp on meter, or using a pickup coil that the wire passes through that will allow an amperage reading without the meter being an active part of the circuit. I was not trying to rain on anyones parade, I merely did not accurately explain my answer. I have 10 years as a senior service tech for an electric motor and generator shop under my belt and sometimes I guess that I just assume that others that are trying to do these types of projects know more than they actually do. I will try to remember that in the future.
That was my mistake. What I should have said was that if you do not know if there is an internal shunt, wire one in and then test the guage with a meter to see if the reading is correct. The use of the dropping resister is after the guage, and therefore will not have an effect on the reading. As far as 60 amps not being an issue in a DC circuit, I have had readings many time that amount on DC circuits. And even though the wire were very hot at the time, other components failed long before the guage crapped out. I have also seen severe damage in circuits where the current drawing device was shutdown suddenly and backfeed current literally melted components. Did you ever wonder why most circuits on a vehicle had 20 to 30 amp fuses on wires as small as 14 guage?? The resister that I was suggesting was merely to stop back feed. The proper way to do amperage measurement is to use a meter that is not a part of the circuit. Either using a clamp on meter, or using a pickup coil that the wire passes through that will allow an amperage reading without the meter being an active part of the circuit. I was not trying to rain on anyones parade, I merely did not accurately explain my answer. I have 10 years as a senior service tech for an electric motor and generator shop under my belt and sometimes I guess that I just assume that others that are trying to do these types of projects know more than they actually do. I will try to remember that in the future.
:laugh: