One of the possibilities to explain the voltage dip when I went up from 1A to 4A was that my test setup was not a sufficiently accurate replacement for the attachment to the raw DC supply in the 1130. If so, the regulator might have maintained its voltage while connected in the 1130 although it wasn't doing that on the bench.
The first thought I had was that the AC bias voltage somehow compensated for load differences, so I varied the bias supply but saw zero change in the delivered voltage. Just before I broke down the setup because I believed the 086 transistor replacement (2N214) was unable to drive enough current due to its lower beta, I had another idea.
Putting the multimeter on the output terminals themselves, rather than depending on my electronic load to display the voltage, I was surprised and pleased to see that the voltage coming from the regulator itself was precisely the same voltage at 1A, 4A and no load at all. Clearly, the voltage drop was occurring on the cables between the regulator and my electronic load, due to the resistance of the cable.
This is great news, as it means that I have only one test left, the full load test while bolted into the machine. I placed the regulator in the machine again. My resistor network produces a resistance of 0.2 ohms and can handle 200W across all the resistors that comprise it. For the +3V regulator, that means we will draw 15A from the supply. If the voltage stays essentially flat under this load, then the regulator is completely repaired and ready to go.
 |
| 0.2 ohm load for testing |
 |
| Load connected to the supply |
I just need to wait until I get my 230V outlet installed to bring up the 1130 and begin some functional testing.
No comments:
Post a Comment