Gdetrailer
PA
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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.
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RKW
Four Corners, New Mexico
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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.
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Ryan
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NRALIFR
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wa8yxm
Davison Michigan (East of Flint)
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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.
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ktmrfs
Portland, Oregon
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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.
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ktmrfs
Portland, Oregon
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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.
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Bobbo
Wherever I park
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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.
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ktmrfs
Portland, Oregon
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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.
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