Overloading A D.C. Inductive Panel Ammeter?
I have no experience in this area. I want to use an inductive DC PANEL AMMETER rated for 100-amps on a battery charger rated at 157 amps max. Their 200-amp inductive gauge has a resolution of 3 ...
Forum Discussion
as mentioned, for DC current either a resistive shunt or hall effect device is used.
If it is a shunt, then overload conditions can lead to quick failure. Depends on how much and how long, it's basically a resistive element.
Hall devices are much more tolerant of overload. First, what is the overload limit for the hall device itself. It could be WAY more than the max range of the meter itself. Hall devices do present a load to the circuit, nothing comes for "free", but the load is milli or mico ohms. But hall devices can heat up.
So, it's hard to answer your question on overload without knowing the spec's on the hall sensor, that's the key. But I'm going to say, it can likely withstand sigificant overload for maybe even hours, days, or forever.
The inexpensive meters I've seen use a common meter and then hall sensors for max range with the hall sensor output set to match meter max range at the spec'd meter range.
Now for the "zeroing" question. Hall devices are a magnetic field sensor. So..... anything that changes the magnetic field will change the reading. Location, anything in the proximity, time of day.
And finally I'll echo landyahts comments. When at a small fraction of max reading unless it is extremely well designed, a hall sensor is very likely to show (a) lot's of reading bounce and (b) significant error due to field variations and poor zeroing function.
In a previous life I was involved with inductive and hall device current measuring devices with high precision, traceable to NBS, etc. The hall design is NOT trivial, and the cost involved in having a linear stable reading is involved. While we had significant patents around the technology, the real key was our in house "trade secrets", that were well protected. That was more important than anything. And we did not buy our hall devices, we could not find sources that gave us the quality we needed. Our hall devices were fab'd in house, again with lots of "magic sauce" and "trade secrets".
If it is a shunt, then overload conditions can lead to quick failure. Depends on how much and how long, it's basically a resistive element.
Hall devices are much more tolerant of overload. First, what is the overload limit for the hall device itself. It could be WAY more than the max range of the meter itself. Hall devices do present a load to the circuit, nothing comes for "free", but the load is milli or mico ohms. But hall devices can heat up.
So, it's hard to answer your question on overload without knowing the spec's on the hall sensor, that's the key. But I'm going to say, it can likely withstand sigificant overload for maybe even hours, days, or forever.
The inexpensive meters I've seen use a common meter and then hall sensors for max range with the hall sensor output set to match meter max range at the spec'd meter range.
Now for the "zeroing" question. Hall devices are a magnetic field sensor. So..... anything that changes the magnetic field will change the reading. Location, anything in the proximity, time of day.
And finally I'll echo landyahts comments. When at a small fraction of max reading unless it is extremely well designed, a hall sensor is very likely to show (a) lot's of reading bounce and (b) significant error due to field variations and poor zeroing function.
In a previous life I was involved with inductive and hall device current measuring devices with high precision, traceable to NBS, etc. The hall design is NOT trivial, and the cost involved in having a linear stable reading is involved. While we had significant patents around the technology, the real key was our in house "trade secrets", that were well protected. That was more important than anything. And we did not buy our hall devices, we could not find sources that gave us the quality we needed. Our hall devices were fab'd in house, again with lots of "magic sauce" and "trade secrets".
