Hello. Recently interested in the topic of power quality, which is generated by portable power generators for every budget, I decided to propose that the one who has an aggregate and an oscilloscope at one time and place examined the output voltage waveform without and under load. It turns out, as it could have been foreseen, that most cheaper (and sometimes even more expensive) aggregates generate a terrible chaff instead of something that is similar to a sine wave about which every user with modern equipment that we attach to these aggregates would wish. At the beginning I am tossing the link to the Stanley aggregate test https://www.elektroda.pl/rtvforum/topic2381701.html where the output oscillograms from this device are included. The second test that the same colleague did is here: https://www.elektroda.pl/rtvforum/topic2386367.html. It is worth watching what the waveforms look like, especially the second aggregate is quite popular. I suggest that you place such runs as much as possible and write what aggregate they come from at what load. I think it will help to dispel the doubts of many people who need to use an aggregate for sensitive equipment and they care about the best quality of energy and from the seller they are not able to get such information or have no way to test it.
I will start from myself. I have a popular old military aggregate Pab-2, whose combustion I once asked my colleagues in this thread: https://www.elektroda.pl/rtvforum/topic3272854.html. Yesterday I measured this aggregate quickly with an old "non-digital" oscilloscope without load and under a load of 75% or about 1.5kW. Here's what I saw: No load And close-up And under load: and close-up.
To my surprise, the quality of the generated electricity is very good and in fact I have never had a problem with any type of furnace, blower controller, fridge, pumps - anything in the power of the unit.
At the same time, I warn that measurements should be made by people with an idea what they are doing because measurements should be made either with a special high voltage differential probe or a suitable probe for a voltage above 300 V with a silencer, and remember that one of the probe leads, i.e. the crocodile clip, is connected to ground and oscilloscope casing which may cause a potential short circuit or electric shock - so remember to make measurements only when you are sure what you are doing !!! or ask someone who has this knowledge.
I invite you to paste photos and discussions. Greetings
Interestingly, in the case of Pab the opposite is true - I measured it a long time ago. Namely, I set the output of the AVR system to e.g. 220 V RMS. I attach a load of e.g. 1.5kW and the voltage jumps up to 230V. The system according to data and reality provides stabilization at + -8%. And as I disconnect the main load and the rest it remains, the voltage drops to about 220V, so the control method in this aggregate is quite good in my opinion.
I did it a long time ago and it seems to me that I did it with an oscilloscope - I don't remember any anomalies except minor surges probably resulting from the arcing during disconnection of the load - I have to repeat these tests with different types of load out of curiosity. I will do it in my free time and post in this thread yet.
Small portable / mobile aggregates in the army are not synchronized with the network. The PAB-2 was therefore not intended for synchronization. Unless some strange modification or performance but I haven't seen one with such low power yet.
@ marekmajdak87 I do not know how accurate your oscilloscope is and why you will not give 100V per plot instead of 200V, but it looks like you have the peak at 400V, which may be the nominal voltage of the capacitors in switching power supplies, so I advise you to be careful. Connect yourself to a rectifier on one diode and electrolyte and see what constant it will be charged to, then load the generator "in front of the rectifier" with a light bulb and remove the load and see what then.