Digitrax PS515

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Performance Report on Digitrax PS515 Transformer

I tested the PS515 for output voltage and current capability. I started at 6 amps load and measured the hot spot temperature and the output voltage while keeping the current constant at 6 amps. The graph below shows the performance:

Essentially, the unit shut down after approximately 27 minutes, although the output voltage at 6 amps (14.9 volts for a short time) was within the acceptable range for all models of booster (Digitrax, NCE, and Lenz).

I re-ran the test with the current set to 5 amps. The MF615 transformer performed well under this condition, stabilizing after about 2.5 hours and continuing to operate. The PS515 tripped off 70 minutes into this test. The test results are shown in the graph on the next page. Final output voltage was 15.19 volts just before the protection circuit tripped. Again, this is fine for the boosters cited above, but I would not rate the unit at 5 amps because of the relatively short shutdown time.

I tried 4.75 amps and 4.50 amps. In both cases I got a fairly quick shut down. Keep in mind that I started these tests with the transformer temperature at about 50 ?C from the previous testing, but in both cases the temperature started to climb indicating a final stable temperature higher than the starting value.

Next, I ran the unit at 4.25 amps. It worked better, but it still shut down after 98 minutes. Again, the output voltage was acceptable at about 15.3.

With the PS515 still at about 51.5 ?C from the 4.25 amp test, I ran it at a steady current of 4.00 amps. The results of this test are shown in the graph on the next page. At 4 amps, the unit stabilized at 65.3 ?C, very nearly the same temperature at which the MF615 stabilized with a 5 amp current load. At 4 amps, the PS515 appeared able to hold the output continuously. The output voltage was 15.53, well within the acceptable range for the Digitrax, NCE, and Lenz group of boosters. A graph on the next page shows the 4 amp performance.

The last test I performed was a loading test. The results are graphed on the next page. The unit is useable for short-term loads up to about 7 amps. Voltage at a 7-amp load was 14.25, again within the acceptable range for the reference boosters. The PS515 turned off almost immediately at a load of 7.38 amps. At this load, the voltage had degraded to 13.40 volts.

I would rate the PS515 as a 4-amp power source. It has a short-term surge capacity to approximately 7 amps.