I have 60hz @120v but less than 55hz @240v.
TM says check the govenor linkage, look fine works well with 120v.
Anybody else have this issue?
I do need a new throttle cable since I broke it at the operator end.
So if anyone knows where I can get a cable or point me in the right direction with low hz.
You can try Delk's for the cable. http://www.de;lsarmynavysurplus.com The telephone for Delk's is: 336-629-0991. You can check the actual output with a meter and see what you are really producing. For most applications you won't see any difference between 55 and 60 Hz. If you are using the 240 VAC single phase output, adjust the RPM to get 60 Hz.
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Frequency is a function of the engine speed. RPM. These are four-pole generators, meaning the engine must turn 1800 RPM to make 60 Hz output. 1800 RPM is 30 revolutions per second. With a four pole head, that means two complete magnetic field reversals per revolution, making 60 cycles per second or Hertz.
If your throttle cable is broke, there is no way to fine tune the governor.
Get the throttle cable fixed and shoot trouble from there.
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I'm not too familiar withyour particular gen set but I know a little about generators and a lot about diesels since I used to design them as an engineer.
First, an opinion as to where to start. I assume you are not overloading the engine when running on 240 or 120.
There should never be a swing of 5Hz even if completly unloaded or loaded.
Therefore, there are two avenue to look at in your diagnosis. One is the engine governing system needs adjustment or repair as it cannot maintain the speed when load is applied.
The second is the frequency meter and its transducer and input are messed up or something is wrong with the winding and switching feeding the transducer. Let's explore each possibility.
On the engine side there might be a low idle screw that you can turn up enough to raise and hold the speed at 60 hz without the throttle cable connected. This is the same adjustment used on any gen set that does not have a separate throttle cable. I adjust my low idle for 55Hz and high idle for 65 Hz so the throttle cable only adjust from 55 to 65 Hz. This protects the voltage regulator on the generator which does not like low speed. as long as you have this low idle adjustment screw you do have to fix the throttle cable before proceeding to diagnose the operational problem.
Running at 60 hz load the engine with a similar load in both 120 and 240 and note, by ear, the speed drop. It will be the same for both loads. If the Hz drops more than about 2 to 2-1/2 from high idle no load to full load then the govenor droop function needs adjusted. You will likely need a device or devices that can apply full load to adjust the droop but it probably can be adjusted by yourself if you can find it in the manual. Droop will set the rpm or Hz spread from full load to no load. Note that some droop is needed for speed stability. Again 2 to 2-1/2 Hz drop should still give very good stability. Instability is called hunting and this occures if the linkage is sticky or droop is adjusted too tight. Hunting is charactorized by the unit never settling down to a constant speed under constant load. The frequency meter keeps oscilating a small amount back and forth back and forth. Note a wandering voltage regulator can cause hunting which resembles droop but in that case the volt meter and the frquency meter are swinging.
There is also a max fuel adjustment and that needs to be checked too. Once you learn the procedures it is easy and fun to tune it up. One of my generators had the fuel screws and droop so out of whack that when I adjusted the droop the unit would slow down and die as it could not get enough fuel. Adjustments will fix that. I am making the assumption that your unit is running on all cylinders well and the exhust note sounds evenand no excess smoke and it starts up well when cranked. The governor fuel settings consist of: Shutdown solenoid plunger position, Droop, Max fuel, High Idle, Low Idle. Each setting has a separate screw. The trick is to follow the manual in sequence as some settings effect the others. Usually all you need is a full load, the frequency meter, and small hand tools, and of course, the manual.
The other side of the equation is the frequency meter or where it is getting its information from. The frequency meter gets a signal from the frequency transducer which gets its input from one of the 6 windings in the generator. Since the voltage reconnection switch that is adjusted for 120 and 240 is moved there may be a problem with which winding is used or something causing an error on the feed to the transducer when the switch is repositioned. One of the electrical guys on here will have to run that down for you. I'm an engine guy!
If you start it and see 60Hz unloaded stop it and then move the switch to the other voltage start it unloaded, same throttle position, and see 55Hz but the gen speed sounds the same to the ear then the problem is the frequency gage system and may be pointing at a bigger problem inside the generator. What I'm saying here is that the engine will maintain the same speed at a given load or no load regardless of the generator switch position. Therefore, your first tests are to confirm it is either the engine or the generator causing the issue.
Hope these ideas help.
Last edited by ETN550; 11-07-2011 at 19:31.
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Thanks to all that responded.
I will get a cable and test the switch.
I do have what is left of the cable clamped to hold 1800 rpm
I'll post with an update after the new is installed.
If you have 60Hz at 120V and the motor does not change RPM then you should have 60Hz at 240V. Check it with a good meter or KilAWatt thing. Frequency is dependent on motor RPM.
Quick update.
The guys at Delk's where great.
Set me up with a new transducer, Hertz gauge and trottle cable.
Not cheap, but runs good now.
Thanks for the help.
MEP-002A Can't get 60hz @ 240v
