Off Grid vs. solar vs. generator Problem

Makes sense. Freq regulation is important for a/c related electronics, much more so than motors and lights. Holding 60 hertz is easy if you are synched up with the grid, which you aren't. Can you reset the engine governor to hold a synchronous speed without tearing it all apart? Should be an easy adjustment. Dunno if your gennies have it, but all the new ones designed for standalone (or synchronous, too) service had a freq counter in the controller with a readout. There is also the possibility that the gennie is emitting some radio frequencies that the wires are picking up and messing with the modem or inverter by screwing up the wave form. Modem distance from the controllers should help with radiated noise.

Second and maybe top suspicion is that the inverter and controller are not too happy with 60 output from the inverter bucking something radically different on the a/c side giving a beat frequency of just under 5 cps that nothing likes.

Governor should be able to hold freq well within half a hertz (as yours is doing) as long as load changes are gradual. Dropping the well pump on mine causes around a 5 hertz drop along with the voltage drop, and no overshoot on recovery. Recovers in less than a second, but it is still there. None of my electronics not on the UPS are that sensitive, so I don't see it, I hear it.

 

Nadja, I would like to steer you to a site that can answer ALL your Kohler Genset questions. Check out Antique Engines Antique Tractors Steam Engines and Old Iron, in the Kohler sub-forum. I think you will find the site helpful for ANY Genset questions, as well as a place to get any manuals for your genset that you might not now have in-house.

As to your Frequency issue, that is a function of the governor setting on the engine, and should be a simple adjustment to get it back to where it should be. without knowing the specific Model and Spec numbers of you unit, it is hard to be much more specific, but in Basic genset setups, you need to get the frequency setup FIRST. this is done by looking at the unloaded Frequency, and the 80-90% Loaded Frequency and then splitting the difference for 60 Hz. so if your unloaded Frequency is 64 Hz and your loaded Frequency is 60 Hz, then you would set your unloaded Frequency at 62Hz, and then check your loaded Frequency, which should be at 58 Hz. Frequency is DIRECTLY related to engine RPM on ALL non-inverter Gensets. Once you have the Frequency set by adjusting the Governor, then you look at the Voltage output of the genset.

Voltage is not directly related to the engine RPM, but that is ONE of the factors that makeup what AC voltage you get from the genset. Again, you measure the Unloaded Voltage, and loaded Voltage, and see just where the difference split lands. Grid voltage is 120 Vac +/- 10%. That means if your unloaded voltage is lower than 132 Vac, and your loaded Voltage is higher than 108 Vac, then your at least as good as the Maximum Grid Spec. Most genset will hold Voltage Regulation at 5% or better. Voltage regulation is accomplished in Four basic ways on gensets. On cheaper gensets, it is done by the basic design of the Field and Stator winding ratios, and is fixed by the design. On more expensive gensets there is a Voltage Regulation System that can be, Passive, Mechanical, Magnetic, or Active. A Passive system, would be like Transformer Regulation, where the AC Output goes thru a Transformer Winding, on its way to the Output. The Secondary Winding then is rectified and feed into the Exciter winding of the genset so that the more current drawn on the Output, increases the Voltage fed into the Exciter. No electronics, just a Rectifier, and a transformer. Mechanical is where there is an adjustment to set the Exciter Voltage, that has some type of mechanical feedback from the Output voltage.(these are rare in todays world) Magnetic is where there are Active electronics in the Regulator. but it is based on a set of Windings, and Magnetic Amplifiers, to control the Exciter Voltage. (Common just in WWII era, until microelectronics came of age) An Active system will have an AVR (Auto Voltage Regulator) usually a "Black Box" or Circuit Board, that will have inputs from the AC Output windings and it will drive the Exciter Field windings directly. There will adjustments on the board or box, for Voltage, Stability, and on better units, Droop. These type AVR Setups can hold voltages inside 2% easily thru 0-120% of Rated Load of the Genset and are very nice if you have one.

There are three basic type of Gensets in the world. Brushed, Brushless, and Inverter. I suspect yours is Brushed. This is where there are Brushes in the genend that carry, either the Exciter Power, or the AC Output from the Rotor, depending on if this is a Fixed, or Rotating Stator (Output Windings) genset. A brushless genend will not have ANY Brushes but WILL have two sets of windings on the rotor, with a set of Rotating Diodes in between, In essence you have two gensets in one. The AVR feeds DC to the fixed Exciter winding, which causes AC to be generated in the rotating Exciter winding. That power is then rectified by the rotating diodes and feed to the Main Rotating Exciter Winding, which then causes AC Output in the Main Fixed Stator windings, which then feed the loads. The Inverter Gensets have become popular in the last decade. They generate their basic Power in DC, and then feed that to an Inverter system inside the genset, that then makes the AC and sets the Frequency, and Voltage electronically, via its controlling microprocessor. The HONDA Series gensets are the most common of these. Very nice for small stuff, and get very good efficiency when used on small loads with the Eco-throttle in operation. If you have any questions specific to your genset, you can post them here, or over in the Kohler Forum, or feel free to eMail "Me", and I would be happy to help.

 

Ok, I was just thinking about your Modem issue, again and seeing how it likely uses a small WallWart Power Supply, to make the DC that it runs on, you might try looking at the WallWart and see what DC Voltage the modem runs on, and then make a different arrangement to provide that power than the WallWart/Inverter/Genset. I have a 12Vdc Buss in the Office, that runs all the Radios, IP Switches, and the WiFi Access Point for the Cabin, as well as the Wx Station and anything else that is basically DC powered. That Buss is run off a 35 Amp 12 Vdc Regulated Power Supply that sits on the Genset Only powered Ac Buss, and has a pair of L16 Batteries in Series, that holds the 12 Vdc Buss up when the Genset is off. No Inverter Switching Noise in the radios and little problems with anything that is AC sensitive. Just a thought...