I have made 5 very short videos of the final testing of the DC Load Unit. I usually don't make videos as I have a voice problem which makes it difficult to understand me. That being said, here is the first video in which I track the stability of a load of 1 Amp as I bring the unit from about 25 Volts down to 0.7 Volts. One limitation which I have had to deal with in these tests is that my bench supplies do not have the power to completely push the load to its limits.
Next I will be testing the temperature point at which the fan turns on and also the point of temperature stability for a specific input wattage of 60 watts.
In the next video I will be testing the circuit that prevents over current damage to the unit. I have arbitrarily picked 6 Amps as the cut out limit. To make this test I am forced to place a power supply across the sense resistor in order to simulate a real over current condition. Once again I do not have a power supply capable of 6 amps with which to conduct an actual + input to - input test of the unit.
The fourth test will be to see if the over voltage limit is sensed at approximately 35 volts and if the circuitry trips the cut out relay. For this test I have series wired two of my power supplies so that a voltage in excess of 35 volts can be put into the load.
In the final test we will hook up the DC load with reverse polarity and turn up the voltage. If the sensor circuitry is working properly the cut out relay should trip before we exceed 2 Amps. Here is the video.
This concludes my presentation of the DC Load Unit "La Carga". Thanks for checking it out.
John
