New to solar and this site and a little problem to solve with my generator
NorthernBoy1
Registered Users Posts: 10 ✭✭
Thank you for the welcome, I live in northern Europe 60
degrees north so not much sun here at this time of year. I have just installed
an off grid/on grid system on 3 phase and wanted to say hi, introduce myself,
share my experiences, issues and hair tearing out moments. We are now up and
running with a 3 phase solar inverter, 20 PV panels, 3 Inverters/chargers (one
for each phase) 200amphour battery bank at 48 volts and a 4KW 3 phase portable
generator that wont work. And its the gen set that has got me here to start with. Happy to share my experiences as and when I can, I have learnt a lot and lost most of my hair in the process.
Generator works the house when isolated from the solar system but the lights flicker. Our inverters are sensitive to voltage input 180-265 volts and need hertz of 45-65. I tested the voltage and got a reading of 277 at the charger so slowed the generator to get 250 volts but I don't know how to test the frequency. Basically it all works fine on grid and off grid but when I switch over to the generator it is not recognized.
Any thoughts?
Comments
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.
Hallo Northern Boy! 60 Degrees north is quite a bit further north than our 50 degrees here in Canada.
Generators are usually controlled in their voltage by adjusting the regulator, not by their speed. Some generators have capacitors in their regulator that set the voltage. Usually the frequency is controlled by the speed as that sets how fast the poles go past the windings, slowing the speed will lower both the frequency and the voltage. You can get cheap multi-meters that measure frequency as well as voltage.
What kind of generator do you have? Is the flickering under load or even with just light loads? Lower quality generators often have dirty waveforms that make LED and fluorescent lights flicker.
Picture looks like Norway so: Med vennlig hilsen
Offgrid in cloudy PNW
MacGyver'ed museum collection of panels, castoff batteries and generators - ready for state of art system install ....
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
My LED lights flicker on my old fashioned Honda EX650 generator but not on my Ryobi propane inverter generator. I find that dimmers plus LED lights on dimmer circuits are the most sensitive to having the frequency off spec. The flickering was much reduced once I tweaked the frequency to the 60 Hz that the North American dimmers were expecting.
Some generators need a resistive load to dampen the ringing caused with light inductive loads. Worth putting a resistance heater on just to test to see if the flicker goes away with resistive load applied. You might try asking more knowledgeable people on the excellent Smokestak generator forum for help with understanding generator issues!
Offgrid in cloudy PNW
MacGyver'ed museum collection of panels, castoff batteries and generators - ready for state of art system install ....
https://www.ashleyedisonuk.com/voltage-stabilisers-660/
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Do you have a Link/wiring diagram for the genset?
-Bill
Inverter frequency 50 Hz
Input frequency range 45 - 65 Hz
Input voltage range 180 - 265 VAC
https://www.physicsforums.com/threads/delta-vs-wye-pros-and-cons.682676/
From the above (last post) is a nice paper on 3 phase power:
http://apps.geindustrial.com/publibrary/checkout/GET-3388B?TNR=White Papers|GET-3388B|generic
Note, normally Wye connected generators and transformers have the center tap of the Wye grounded (and Delta may have a center tap of one of the windings grounded)... If the tap is not grounded (effectively creating a neutral), the "N" to Lx voltages may float/vary (based on your loads and any parasitic AC or DC current paths to ground).
3 phase AC off grid power systems can be very complex... Details matter (generator and load types/connections). And for larger/complex systems, sometimes even power engineers make mistakes.
-Bill
-Bill
A 1,500 or 3,000 RPM genset would have to run at ~6x normal RPM (9,000 or 18,000 RPM) to generate ~300 Hz. A 50 Hz genset running at that RPM would not be long for this world. (all things being equal).
Also, the Hz reading has to be the same for all phases (there is only "one frequency" from a 1 or 3 phase genset or utility power). A "reasonable" Hz (frequency) reading from a 50 Hz genset would be something between 40-60 Hz (if the motor RPM was anywhere near correct). And many mechanically governed gensets "should be" at worst, 50 Hz +/- 5 Hz. At best, probably +/- 2 or 3 Hz for a typical genset.
If you are actually reading that frequency, I would suspect either the meter has something wrong or the AC output of the genset is seriously broken.
-Bill
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
An inverter type will vary speed with load, saving fuel and running quieter with lighter loads. They have electronics inverting internal DC to the AC output, and I'm wondering if there's something gone wrong there, or maybe a stepped output waveform confusing the meter?
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
Generally, you adjust RPM for frequency, and output Voltage via the voltage regulator (some are fixed output regulators and would need servicing to "adjust" the output voltage). Placing some sort of load (very roughly 100 watts per leg minimum--Or small electric heaters/load bank... Avoid "active loads" like computer power supplies--Many have "very difficult" current waveforms for gensets/inverters to drive) on the Genset can help stabilize readings.
A couple of links from this post:
https://forum.solar-electric.com/discussion/comment/358047#Comment_358047
http://www.screenlightandgrip.com/html/emailnewsletter_generators.html
http://www.screenlightandgrip.com/html/emailnewsletter_generators.html#anchorSquare Wave Generators
-Bill
The inverter/charger has a (sometimes adjustable) range in which it will qualify/drop generator input. Some also have a delay time for warm-up, maximum total current, and/or maximum charging current which might be worth checking in case one of these settings got pooched somehow.
My understanding is pretty rudimentary though, and I'm not familiar at all with that generator brand, so FWIW.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
My suspicion is the unit would first be unqualified due to over voltage, the consequent adjustment of rotational speed altered the frequency outside of frequency qualification range. It was stated the voltage is now 265V with strange and impossible frequency numbers, the voltage may still be too high as the RMS value has some margin of error on virtually all multimeters, reducing speed further, would only result in further frequency reduction.
https://engineering4uu.blogspot.com/2017/04/speed-and-frequency-of-synchronous.html
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Just to explain the concept of "Frequency" - A waveform can be a superposition of many frequencies. A perfect and endless sinewave has only one frequency, the "fundamental". In your case this would be 50 Hz in your case.
An actual dirty generator waveform (with harmonic distortion, spikes, variability) has many "frequencies", with additional frequencies going along for the ride that make up the distortions. Usually the main extra frequencies seen are the "harmonics" such as doubles, triples etc.
Depending on the meter's frequency response, meters can latch onto these other frequencies, many of these frequencies can be higher than 50 Hz and this may explain your strange measurements. You should try your meter on the inverter outputs and other sources, read the manual in detail and become familiar with how it works and responds.
Generator waveforms can have low frequency clipping off of the peaks at high loads and high frequency ringing at low loads, both of these will overlay extra frequencies onto your waveform.
Faulty regulation can also make for strange effects and problems like flickering lights. I bought a cheap "DSO Nano" credit card sized digital oscilloscope for $100 - Best investment in understanding off grid power troubleshooting ever!
These handy little scopes have a frequency meter mode and have waveform analysis/measurement modes. They are a great thing to have to measure, diagnose and help you fix strange generator/inverter behaviors. Tested a neighbour's near new Yamaha inverter that was burning out expensive controls on his pellet barbeque. It was shocking to see the spikes that were coming out of his generator waveform.
Offgrid in cloudy PNW
MacGyver'ed museum collection of panels, castoff batteries and generators - ready for state of art system install ....
https://www.electronics-tutorials.ws/accircuits/sinusoidal-waveform.html
and the engine speed controls the frequency of the sinewave. So engine speed at no load needs to be set to generate about 51 or 52 ( or 62Hz, depending on your electrical gear) Hz and as the load increases, the engine governor attempts to maintain the desired speed, but often looses a Hz or 4.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Just be very careful before attaching your O'scope to your AC Mains. Most "laboratory scopes" are not setup to safely make arbitrary connections to 120/240 VAC mains (i.e., lots of smoke and tears).
-Bill
Lab type scopes powered by 120 VAC may have their reference ground input tied to AC neutral or ground so you have to be very careful where you attach the probe ground to avoid shorting line to ground.
Portable internal battery powered instruments like the DSO Nano V3 series scopes are floating on both inputs. This is both a blessing (makes connecting less problematic) and a potential danger. When you connect them you have to be aware that in the event of a fault the case may take on a voltage somewhere between line and ground. Very happy with these little scopes though. They seem well made by Seed Studios and are open source too.
Forgot to mention that for use on 120 VAC you need to make or buy a 10:1 probe as the DSO scope has a maximum 10 V/division full scale range (i.e. about a 100 V range) and you may need a BNC type connector adaptor for the probe as the scope comes with a set of micro circuit clips on a small headphone type plug. Alternately you can make your own voltage divider probe with a 10 to 1 ratio attenuation circuit of appropriate 50 k / 500 k resistors or with 20:1 ratio (for 230 volt folks).
Offgrid in cloudy PNW
MacGyver'ed museum collection of panels, castoff batteries and generators - ready for state of art system install ....
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.