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 - ..... snip

time2roll wrote:
My question to Progressive:

Still curious on an intermittent error. If the voltage or ground briefly drops every 60 seconds does the EMS reset the timer at each error? Or does it connect at 136 seconds and wait for the next error before disconnect? Thank you

Today from Progressive:

If the voltage falls below 104 Vac for more than 6 seconds, the EMS will disconnect. A loss of ground will cause an instantaneous disconnect. When an error occurs and then the cause clears, the time delay starts. In your example, if the error occurs every sixty seconds, power would not be restored, because the delay would be resetting to zero each time.

My Comment: This is in effect monitoring of the connection for the entire 136 seconds. Power and connection must remain stable within specs for the entire delay timer or timer resets. I understand the effect is to have power off a minimum time for the air conditioner internal pressure to bleed down.

That wasn't my experience, even though this statement came from Progressive ... if input voltage to the EMS is reduced it will disconnect power to it's output the instant input voltage drops below 104 vac, not 6" later. I've demonstrated this with my own EMS on my workbench and DVMs connected to monitor both input and output voltage. However, there is a caveat to this - since I don't own or have ready access to a Variac I can use to externally draw down input voltage to the EMS the only way I can do this is use the trim pot within the EMS ... and when I do so the EMS does disconnect the moment voltage drops just slightly below 104 vac, not 6" later. Since I don't have a schematic of the EMS I can't say for sure whether the difference in methodology would impact the way the EMS behaves but lowering the voltage using the trim pot in the EMS did in my case trigger a disconnect immediately.

As for your comment about "monitoring", the EMS doesn't just monitor for 136" (or 15" in the case of a hard wire model with the jumper in place) but rather continuously, as in anytime it's seeing power applied to it's input. The EMS will disconnect anytime it detects an error in the incoming source or if the error is present when the unit is plugged in it won't connect at all, in which case it will display not only an E* error code but also a PE* error code. Once a disconnect then an eventual reconnect occurs delay timing starts again, just as one would expect ... so although I've read your previous comments several times about monitoring I'm not sure I understand what your concern is. :h The unit does what it's supposed to do - not pass on power to the trailer anytime it detects an error and will only reconnect (with the selected delay) once that error is no longer present. :B

As a FOOTNOTE to this ...

The more I think about it having the EMS wait 6" before it actually disconnects because of a low voltage situation does make sense as it would be an effective way to avoid nuisance disconnects when the source voltage was hovering just above and below the 104 vac threshold. Monitor any source voltage with a DVM and voltage, even when measured in just 1/10ths of a volt, will vary constantly 0.1 or 0.2 or 0.3 volts so I can see how one moment it might be 104.1 then swing to 103.9 and cause the EMS to disconnect if there was no delay ... annoying for sure if voltage otherwise would swing back above 104.0 volts a moment later. I wonder if this 6" delay is applied also in a high voltage threshold as well? :h This probably also explains why the hard wire versions have a minimal delay of 15" instead of none at all ... but what's the significance of 15", why not any delay greater than 6"? Hmmmmm. :h

Darn, sure wish I had a Variac so I could do some accurate testing. :R