Advice needed for electric pedestal tester

SoundGuy wrote:
Both of these statements infer that the Progressive EMS unit is using this 136" time delay to analyze the input signal before deciding it's stable enough to pass along to the trailer. This is incorrect as the analysis takes no time at all - rather, delay is set at 136" in order to protect an A/C compressor, preventing it from restarting until head pressure has diminished to a safe level. Progressive EMS delay for the portable versions is fixed at 136" but delay for the hard wire versions can be shortened to a more convenient 15" by removing an internal jumper. I took this one step further with my own EMS-HW30C by wiring in an SPST switch in place of the jumper so I can simply switch between the two delay times, 15" or 136", rather than have to open the case and fool with the jumper. :B

time2roll wrote:
OK and say intermittent fault every 30 seconds. Does not the timer reset each time?
Or does PEMS just check the instant the timer expires and calls good or no?

The Progressive EMS automatically disconnects anytime it detects an error in the incoming service and will not reconnect until that error disappears. Whenever an error is detected output power is disconnected instantly and what is normally a blank cycle on the display will then show PE*, with * being a number representing the nature of the error, such as PE2 which means loss of ground. That previous error code remains until power feeding the unit is removed completely and then correct power (in this case with ground intact) is restored, in which case that PE* error code will be cleared and show blank again until such time as there may be another error. In a case where the EMS is initially plugged into incorrect power the unit will show an error code (such as E2) plus a PE* code (in this example PE2) and will never output power to the trailer until the error is removed or the unit is disconnected from source power and then plugged into power with no errors.

FWIW, I wired up a jig on my workbench so I could demo these various sequence of events, using loss of ground as my "error" as it's one of the most common I've run into, along with low voltage, but is one of the easiest to emulate by simply adding a switch in the ground wire feeding the EMS so it can easily be disconnected / reconnected, emulating an error in source power. None of this however has anything to do with the unit's time delay setting(s), of which the longer 136" delay exists solely for the purpose of allowing A/C compressor head pressure to diminish to a safe level before power is restored to the trailer.

Hopefully this clarifies how the Progressive EMS works. :)