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Generator CAT3306 - 180kVA - 380V output...when running for hours. Suddenly output voltage drops to 300V, same rpm/Hz drops during 2minutes, then rpm quickly goes up and frequency passing 54 Hz and generator engine goes off. Same symptoms come up after restarting. What do you guys think... Thx for yr help
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It could be several things but it sounds like it just running too slow. I would the engine rpms first. Depending if is a two pole or four pole and if your 60hz or 50 Hz on the needed unloaded rpms.
Example: 2 pole 60 hz. Engine needs to be running at 3600 rpm loaded and 3750 rpm unloaded; unless, it has a fuel saving mode.
A 4 pole 60 hz would running half this rpm. The 2 pole producing 50hz would have the engine running at 3000 rpm loaded (about 3100 rpm unloaded)
Now in order for the 50 hz system to produce the same output voltage it requires a different alternator than the 60 hz version; otherwords, You simply can't convert a 60 hz to 50 hz version without changing the alternator by changing the engine speed.
Output voltage is based on 3600 rpm @ 60Hz. Sounds like your generator is over speeding slightly. Put a Frequency meter on the output of the generator and tune it to 61.5 Hz, that will get your generator in the 3600 RPM range.
Not sure what you mean "high voltage rpm power generator out", however many people have asked how to adjust the engine for proper voltage output. On generators with~out a voltage regulator, I adjust the engine RPM by using a digital voltage meter that has a Hz setting. Adjust the governor untill the meter displays 60 Hz. With the geneator producing 60 cycles, I know that the engine is turning 3600 rpm (the engine produces max hp when it is turning 3600 rpm). At this point, read the voltage output to verify that the range is between 115 ~ 120. On generators with a voltage regulator, verify/adjust that generator is producing 60 cycles then adjust voltage by turning screw at the regulator (some regulators are sealed with potting compound and can not be adjusted). If your power demands are not that great and you appliance can operate at 50 cycles, adjust governor as needed. Lowering to 50 cycles will also reduce output voltage. Good luck
On the engines carb. is a governor rod should connect to the front case of the engine. This rod should have an adjustment to slow the engine speed. BUT,,, are you reading the generator unloaded or without any thing plunged into it? Once you have the generator loaded with a device, the voltage should drop to a constant 240vac. 150 rpms should not make that big a difference on the voltage output, and if running under load the RPM's should drop also..
I am not familiar with this make of generator, however I am thinking that voltage regulation and rpm are tied together with this unit. The generator MUST have an output of 60 hertz. This could be 63 hz (when the load comes on it drops to around 60). If the frequency is NOT at the above specs you will burn out anything with a transformer or motor. Now this translates to around, minimum of 3600 rpm on the engine. If you have access to a frequency meter (a kill-a-watt) you can set the speed. I found it best when using the kill-a-watt to use it with a minimum of a 10 foot extension cord. Set the throttle speed so that your frequency reading is 63 hz. If this is the non electronic voltage regulated type of generator, the voltage should come up to around 120 volts and the frequency should be at 63 hz.
joe
Look under Low Voltage (Parallel ) WYE Connection
This is for a 12 lead alternator. I believe this is what you have. This will give you 120 / 208v 3 phase. Make sure that your connections are strong physically and well insulated electrically to prevent a nasty accident. This is a good, solid, dependable unit. Make sure that you have your frequency set around 61- 62 hz (depending on load) so that when the unit is loaded, the frequency drops to 60 hz. I have seen many units set to run quietly and save fuel. This being done, the rpm is too low and the output frequency is below 50hz. Anything with a coil (motors, transformers) will burn out due to an improper frequency.
According to the parts pdf, there is no voltage regulator. Voltage is adjusted by the rpm of the engine. If your have a meter that reads hertz (Hz), you can set the engine rpm by adjusting hertz to 60 cycles (Hz). At 60 cycles the engine is running at about 3600 rpm. Most engines develop their max horsepower at this rpm. If you are loosing power/voltage and the engine speed is not dropping below 3600, than most likely could be problem with capacitor, brushes or diode (bridge diode). The diode converts ac voltage from stator to direct current to power the magnet (rotor). Check for brush wear and test capacitor for value printed on part. It should test with 5% of stated value. Diode can also be easily tested with meter. Good holidays
This problem is either that the engine RPM is too low (most likely), or that there is something amiss in the voltage regulation. Get yourself a DMM that measures Hz, plug it into the output and see if you get 61.5 Hz, if not look for the adjustment on the governor spring. On some Powermates this is a screw that pressed on the governor arm, on others it's a little tab the governor spring attaches to that you bend. Do this at no load. FWIW 61.5 Hz is also 3750 RPM of the engine.
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