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Progressive Industries EMS and Powerline frequency error

Ed_Gee
Explorer II
Explorer II
Recently while traveling through eastern Oregon and possibly western Idaho we experienced several instances where my Progressive Industries EMS-PT30X would give a line frequency error and not allow power to my RV. Since we really needed power for AC I removed the EMS unit... and all worked well.

My Question: has anyone else experienced this issue? Does anyone know of a way I could have bypassed the EMS line frequency error and still allow other protections to continue? I may pose,this question to Progressive Industries later....
Ed - on the Central Oregon coast
2018 Winnebago Fuse 23A
Scion xA toad
17 REPLIES 17

ktmrfs
Explorer
Explorer
Bobbo wrote:
ktmrfs wrote:
BTW on my PD EMS unit that is installed in the trailer I can bypass it with the switch on the "dongle" unit. Nice when using a generator with an unbonded neutral.

My bonding plug (less than $2 to make) means I don't have to bypass the EMS. It protects against generator failure too.


I generally also use a bonding plug but on occasion have misplaced it so being able to bypass the EMS has been helpful.
2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2015.5 Denali 4x4 CC/SB Duramax/Allison
2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son!

Bobbo
Explorer II
Explorer II
ktmrfs wrote:
BTW on my PD EMS unit that is installed in the trailer I can bypass it with the switch on the "dongle" unit. Nice when using a generator with an unbonded neutral.

My bonding plug (less than $2 to make) means I don't have to bypass the EMS. It protects against generator failure too.
Bobbo and Lin
2017 F-150 XLT 4x4 SuperCab w/Max Tow Package 3.5l EcoBoost V6
2017 Airstream Flying Cloud 23FB

ktmrfs
Explorer
Explorer
the only time I would expect the EMS to find a frequency out of range is when connected to an open frame 3600rpm generator that is running at the incorrect rpm. (3600 rpm= 60hz).

Frequency of the normal "line" coming in is very tightly controlled, seldom will you see even a 1Hz error and the total error in cycles over 24hrs is in the handful. for the grid to work everyone in the grid (3 in the country, east, west, and texas) must be exactly at the same frequency and exactly in phase.

so, If you were connected to campground power and the grid, I suspect the EMS has a fault. BTW on my PD EMS unit that is installed in the trailer I can bypass it with the switch on the "dongle" unit. Nice when using a generator with an unbonded neutral.
2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2015.5 Denali 4x4 CC/SB Duramax/Allison
2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son!

ktmrfs
Explorer
Explorer
the only time I would expect the EMS to find a frequency out of range is when connected to an open frame 3600rpm generator that is running at the incorrect rpm. (3600 rpm= 60hz).

Frequency of the normal "line" coming in is very tightly controlled, seldom will you see even a 1Hz error and the total error in cycles over 24hrs is in the handful. for the grid to work everyone in the grid (3 in the country, east, west, and texas) must be exactly at the same frequency.

so, If you were connected to campground power and the grid, I suspect the EMS has a fault. BTW on my PD EMS unit that is installed in the trailer I can bypass it with the switch on the "dongle" unit. Nice when using a generator with an unbonded neutral.
2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2015.5 Denali 4x4 CC/SB Duramax/Allison
2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son!

wa8yxm
Explorer III
Explorer III
Ed_Gee wrote:
NRALIFR - the error code was E7 ... high frequency. Not sure if my DVM will measure frequency.... will check and then keep this in mind...


Some will. some won't and the Kill-A-Watt meter is what about 30 bucks, it's about a kilo-buck worth of meters in one box
Voltage
Frequency
Volt-amps
Watts (NOTE these last two are not the same thing)
Power factor (That's the relationship between watts and V-A)
Kilowatt hours
And I think one more (not sure without going to kitchen

I mentioned power line noise up thread. the PI unit might be more or less senistive to power line noise than either the Kill-a-watt or a DVM with the ability to measure frequency (I have some that do and some that don't by the way)

A 'scope is the only real way to be sure when you get multiple devices giving different info

Of course the final option is bad Surge Guard. but not ready for that yet.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

NRALIFR
Explorer
Explorer


:):)
2001 Lance 1121 on a 2016 F450 ‘Scuse me while I whinge.
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RKW
Explorer
Explorer
For any interconnection (Western Grid, Eastern Grid, ERCOT Grid etc.) the frequency is global. That is to say the frequency is the same throughout each interconnection. In the Western Grid, for example, a control center in New Mexico will read the same frequency as a control center in Washington State. There are no low frequency areas or high frequency areas within an interconnection. If there is a system disturbance, like a sudden loss of load or generation, there will be what is called a frequency excursion. Rarely, if ever, will the excursion be severe enough to cause damage to the customer's equipment. The tripping and separation schemes in an interconnection won't allow it.

So I said all that to explain my observation that the frequency parameter in an EMS is mostly superfluous. The frequency will either be acceptable or it will be zero. The power is either there with an acceptable frequency or it's not there and you are in the dark. I realize this post doesn't answer any thing in the OP, but I wanted to throw it out there for the edification of our forum members.
Ryan

  • 2015 Ford F250


  • 2015 Rockwood Signature Ultralite 8280 WS


  • Dual Honda EU2000i Generators




    The wages of sin are death; but after they're done taking out taxes, it's just a tired feeling.

Gdetrailer
Explorer III
Explorer III
Ed_Gee wrote:
To repeat some info - the frequency error occurred at three different RV Parks... all in the eastern Oregon area... I have yet to determine if my DVM measures Frequency.... but I must consider the EMS may have a problem.


I would concur that your EMS is most likely at fault if it is failing on frequency on shore power from the PoCo.

If EMS is faulting over a less than +(-) 2Hz change from PoCo then it must be the EMS.

If it was faulting from your gen only then the issue most likely would be coming from the gen in the form of gen over or under RPM.

EMS systems do fail.. Sometimes they get fussy.

Heck I have a UPS unit that gets bent out of shape when running from my genny and the genny is under light load and constantly switches between UPS battery and shore power unless I add a couple of amps of load to the gen to drop the frequency slightly.. UPS units must synchronize between the shore power and the inverter in order to switch to battery or from battery so they are sometimes persnickety on frequency.

Ed_Gee
Explorer II
Explorer II
To repeat some info - the frequency error occurred at three different RV Parks... all in the eastern Oregon area... I have yet to determine if my DVM measures Frequency.... but I must consider the EMS may have a problem.
Ed - on the Central Oregon coast
2018 Winnebago Fuse 23A
Scion xA toad

Gdetrailer
Explorer III
Explorer III
DrewE wrote:
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.


Most clocks now days do not depend of the line frequency for time keeping, heck even finding an new old fashioned synchronous motor driven clock is pretty difficult to impossible find now days. Most clocks are fully electronic driven with a crystal time base oscillator and only periodically "sample" the line frequency to snap the oscillator back into sync. Lots of battery powered clocks now days and much of the world uses their cellphones for time/alarm functions.

Induction motors do not care very much about frequency and are often marked 50Hz/60Hz which means they are designed to operate a bit below 50Hz to a bit above 60Hz and still operate efficiently and be operable anywhere in the world.

Much of the electronics world have moved over to switching power supplies which 100% ignore line frequency by rectifying and brute force filter the incoming AC line to DC then run the DC through a chopper at high frequency.. They too are also pretty much always will be rated 50Hz/60Hz which allows that power supply to be universally used anywhere in the world..

Line frequency from PoCos now days does indeed vary..

Here is a couple of snap shots from this morning..





Did see a 60.2 briefly but was not able to get a photo of that..

The frequency was changing consistently every second and I verified that on all three UPS units I have with that display while the same model were manufactured in different yrs.

Typically I will see a constant 59.9 or 60.1 for hrs on end, today, not so much.

While these examples are not +(-)1 Hz they do show that the grid frequency is not "rock stable".

I suspect however that the OPs EMS has a fault and will require replacement since it should tolerate enough frequency variation that comes from not only the POCO but a generator. Most generators will vary from 62Hz unloaded to 58Hz fully loaded.

wa8yxm
Explorer III
Explorer III
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.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

DrewE
Explorer II
Explorer II
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.

time2roll
Nomad
Nomad
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.

Ed_Gee
Explorer II
Explorer II
NRALIFR - the error code was E7 ... high frequency. Not sure if my DVM will measure frequency.... will check and then keep this in mind...
Ed - on the Central Oregon coast
2018 Winnebago Fuse 23A
Scion xA toad