Progressive Industries EMS and Powerline frequency error

theoldwizard1 wrote:
Very unusual for 2 reasons?

1) Power line frequencies have to maintained very close to 60 Hz so that power companies can buy and sell power to each other. A very small fraction of 1 Hz.

Believe it or not, most electrical loads (like an A/C) can tolerate +/- 5-10% shift in frequency. They won't be as efficient and might run hot.

Some years ago the standards for maintaining power line frequency were loosened some.. I am not sure what it is today but it's not as tight ads it was years ago..
Of course it is important to stay fairly close to frequency or damage may occur to Generators and other equipment (As in total loss damage).

There are other issues however that can cause a "Phantom" frequency error. Power line noise can trip the senser in the protectors. Without a scope on the line.... hard to tell.

The error is most likely caused by some noise on the power lines that the EMS is somehow interpreting as the incorrect frequency. The power supply from the electric grid is quite well regulated in terms of frequency, within 1 or 2 Hz at the very worst under normal conditions (instantaneously) and within a tiny fraction of a percent when averaged long-term. The long-term accuracy is due to the need to keep clocks that reference the power line from gaining or losing time on average: a 1% error there would mean their gaining or losing about fifteen minutes over the course of a day, which is clearly not acceptable.

The main problem you might see if the frequency were actually well out of specification are some clocks and timers running fast (or slow)--these days, that's mostly mechanical appliance timers, as digital electronics generally use a crystal oscillator or similar timebase independent of the line frequency. Synchronous AC motors will try to run at a different speed, but for most household devices that's not a concern as their actual speed is usually a result of mechanical loading rather than synchronous line frequency. It would take a quite large deviation to cause "real" problems that might damage things.

Did you inquire with the RV park about the issue? Any chance they were off-line and running a backup generator? I wonder if there was some other line noise in the connection that may have fooled the EMS. Maybe that is not possible.

If you use the bypass I would recommend monitoring the voltage manually.

NRALIFR - the error code was E7 ... high frequency. Not sure if my DVM will measure frequency.... will check and then keep this in mind...

There’s no way to bypass a single error condition. The unit is either plugged in-line, or it isn’t.

The display on the unit continuously scrolls, at 2 second intervals, all AC power information: voltage(s), current(s), frequency, error code, previous error code (if applicable).

What frequency was it displaying?

If AC power frequency deviates plus/minus 9 Hz from 60 Hz, the EMS will shut down AC power. An Error code of E 7 will be displayed when the frequency is high; and an Error code of E 8 will be displayed when frequency is low.

What error code was it displaying?

I would have checked the frequency with a DVOM, and confirmed that either the park power was out of spec, or the EMS was faulty.

:):)

I had the same issue with my progressive in one campground. I was getting the frequency error and one side was reading 89. I had no clue and the book said to call customer support. I tried but no one answered the phone.

The EMS has worked perfectly in the month and a half since in different camp grounds.

No idea what high frequency will do so I did just as the OP did and unplugged it for the night.

Very unusual for 2 reasons?

1) Power line frequencies have to maintained very close to 60 Hz so that power companies can buy and sell power to each other. A very small fraction of 1 Hz.

2) any instrument that measures frequency likely has a crystal controlled built in oscillator. These are also very accurate. They might shift a small amount over a wide temperature range.


Believe it or not, most electrical loads (like an A/C) can tolerate +/- 5-10% shift in frequency. They won't be as efficient and might run hot.