Take another look at the diagram in section 4.4
It clearly shows the current path from a properly PROTECTIVE EARTHED but but faulty equipment goes through the PROTECTIVE EARTH CONNECTION which is of (tested at installation time), low resistance, to the earth bar, then via the earth bar-neutral...
Refer to AS3000, section 5.4.6
This states that metal building materials possibly in contact with lives wires must be earthed to the earth bar directly via the protective earth. Maximum resistance between them shall not exceed 0.5 ohms.
It is usual to meet requirements by enclosing the...
What is the "scales"?
Is it say, a weighbridge in the middle of an industrial site, with welders, compressors etc. scattered around.
In that case an isolating and regulating transformer may be required. What does the HDMI feed? Is there optically isolated communications?
The bare minimum of...
Electric fence energizers are normally tested by checking pulse voltage output over a 500 ohm resistor, simulating a loaded electric fence. Rated voltage (normally about 5 kv is easily delivered.
A low powered transformer has 12.5 ohms and 60mH (@1kHz) secondary impedance and primary impedance...
Possibly a strong Radio Frequency transmitter was operating near the circuit, this could cause conduction in the diode, especially if the circuitry happened to resonate at the frequency.
Hakko FX888D is the entry level Hakko. Better is the Fx950, (I have one, and it is very good.) The digital version is the FX951, it has sleepmode, which is good if you are inclined to forget the iron is turned on. These ones are 70 watts, which I regard as a minimum these days.
85 different tips...
Gidday Keith, I have a megger similar to that one, its only fault is that it indicates about 25 k when I short the leads together. So I don't know whether there is a short or a significant leakage.
My recommendation for a utility "megger" would be the KYORITSU 3132A. This is a basic instrument...
One thing that I really dislike about the cheapo DMM's that I have used, is the slowness of the reading updates. For instance on one meter I have got, it can take several seconds for the ohms to settle.
Whether the meter has effective internal protection against voltage and current overload is...
I have noticed the message on gauges that I have been testing for accuracy, gauges in the range from 100 kPa up.
Always there is a bubble in the filling liquid, which is glycerine in the gauges that I test.
Anyway, I have not seen any significant difference in the readings whether or not the...
Its only a small charger, 4 amps max, supposed to drop back to trickle charge automatically, and yes it was on continuous charge, but I look after it myself, so the electrolyte was definitely above the plates.
The theory that a clip lead fell off, causing a small spark, that ignited the...
For interest, here is my battery which exploded one day. It was under trickle charge from an electronic type charger, which still works. The battery cell caps were not removed for charging, but I don't know why it blew up.
Ray.
I live in country NSW, Australia, and I checked out my pole transformer yesterday. There are two earths coming down the pole, they are spaced 180 degrees, and they go into the ground straight out from the pole, forming an underground 'T'.
At the top of the pole, one earth connects to the casing...
