15-10-2013, 02:28 PM
Quote:It might be worth checking the electrolytic caps. for leakage or loss of capacity, prior to any testing. A few minutes testing with meters and wattful resistors will tell you what it is capable of - but don't forget to monitor the ripple on the O/P d.c. as you vary the load and also keep a watch on the transformer temperature.
If you draw about 100 mA from it, the on-load voltage will probably drop to something in the region 425 - 450 v.d.c. At 450-v., you'll need a 4500 Ω resistor at 50-watts. At 425-v., 4000Ω at about 45-watts. The on-load voltage drop primarily depends on the current-capacity of the HT winding of the transformer. Since it uses a C-L-C reservoir / filter for the HT, the difference between no-load an on-load voltages will be significant. The HT, on-load, might even drop to 400-v. All depends on the transformer. Being ex-MOD, I expect that the rectifier's current rating is substantially more than what the transformer can provide.
Have fun - but be careful with that HT: 450 v.d.c. can really hurt! Yow! Confused
Thanks Skywave, I appreciate your advice.
I have checked out the electrolytics, they appear to be good.
Paul
