Lister Engine Forum
Lister Engines => Things I want to Buy => Topic started by: Listerational on July 22, 2016, 08:57:57 PM
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Hello,
I would like to automatically disconnect the electrical load on my generator when it senses that I am out of gas or is turning off for some other reason. I am wondering if a frequency sensor would do the trick. Would anyone please recommend a good frequency sensor for my application? My generator is a
POWER LINE, 10-HP, 7.35-KW.
Thank you,
Jim
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So what you need is a Frequency monitoring relay with adjustable hysteresis, I will work on finding a part number that would work and send you the link.
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Take your pick
http://www.crompton-instruments.com/downloads/2015/EPP-2040-1115_protectors_201115.pdf
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Warning, some of the frequency (and voltage) monitoring relays can't cope with low speed engines and non smooth sine waves. Check with the vendor.
I finally went to a Siemans model for my neighbor's propane conversion of the DES 8/1 with an ST-3. It does true RMS so is completely waveform and is entirely frequency independent for voltage monitoring.
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you could also use a beefy relay with 120V coil. As the RPM's drop, so does the voltage and the coil will drop, cutting off the load and you don't have to reflash the rotor.
This would work with some fiddling to get to coil to let go before the demag happens.
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I would suggest a voltage monitoring relay over a frequency style, in that link there is plenty to chose from. Ive never actually messed with the frequency relay on a slow speed but it makes since how it wouldn't work well with it. I was going to set one up on my small yanmar homemade generator for a two speed throttle using a solenoid.
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you could also use a beefy relay with 120V coil. As the RPM's drop, so does the voltage and the coil will drop, cutting off the load and you don't have to reflash the rotor.
This would work with some fiddling to get to coil to let go before the demag happens.
That sounds like the craziest idea I have ever heard. I love it....
May I ask the definition of 'reflash the motor'?
Thanks,
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I would suggest a voltage monitoring relay over a frequency style, in that link there is plenty to chose from. Ive never actually messed with the frequency relay on a slow speed but it makes since how it wouldn't work well with it. I was going to set one up on my small yanmar homemade generator for a two speed throttle using a solenoid.
The reason that it makes sense is it because the ratios are much smaller than in a 3600 rpm? 60hz/3600rpm vs 60hz/1000rpm.
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Reflash is common jargon for re-magnetizing the rotor with a dc battery or similar power source. The generator rotor will sometimes lose its residual magnetism and thus become unable to start up power generation until the rotor is "flashed" or magnetized once again. One way that a generator loses its residual magnetism is when it is improperly shut down under load.
dieselgman
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I would expect that you'd get relay chatter trying to use a relay with resistor to coil as a low voltage cutout, due to the low frequency power pulses on a CS.
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Take your pick
http://www.crompton-instruments.com/downloads/2015/EPP-2040-1115_protectors_201115.pdf
Thanks for all of the instructables This is great stuff....
Looking at the link to Crompton Instruments I did not find any plain voltage monitors but phase and voltage monitors. The one that I believe applies best to my 10HP, 7.35KW, SINGLE PHASE LISTEROID is
PSF/G3-173/240 http://www.crompton-instruments.com/downloads/2015/EPP-2040-1115_protectors_201115.pdf
Do you think this will work with my single phase generator?
Thank you ....
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Check out page 6 they have over voltage , under voltage , and both on there.
Take your pick
http://www.crompton-instruments.com/downloads/2015/EPP-2040-1115_protectors_201115.pdf
Thanks for all of the instructables This is great stuff....
Looking at the link to Crompton Instruments I did not find any plain voltage monitors but phase and voltage monitors. The one that I believe applies best to my 10HP, 7.35KW, SINGLE PHASE LISTEROID is
PSF/G3-173/240 http://www.crompton-instruments.com/downloads/2015/EPP-2040-1115_protectors_201115.pdf
Do you think this will work with my single phase generator?
Thank you ....
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I use one of these to pull my fuel rack closed is there is a loss of power out if the generator. For example, if a belt broke, the device would shut the engine down due to loss of power. Same for over heat, separate circuit attached. If I had it to do over, I would have the magnet engage and hold a switch on. Thus when the engine lost power or speed, a big spring would pull the switch into the off position due to loss of power and thus the magnet holding it on would disengage. This system could easily pull a relay.
http://www.murcal.com/Catalog/Rack-Pullers/RP2309B-Push-Pull-Solenoid (http://www.murcal.com/Catalog/Rack-Pullers/RP2309B-Push-Pull-Solenoid)
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I concur with the Energized to Run (ETR) methodology. Some manufacturers used an energized to shutdown (ETS) control system, but those were complex and less reliable. Lister has used a simple Energized to Run safety fuel control solenoid for decades.
dieselgman
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The same theory applies to the Emergency stop circuit on a CNC machine, normally closed. So in the event of a broken wire of faulty switch it alarms the machine out rather then on a normally open circuit with the same issue the machine will never sence it and when the part pulls out of the vise and is working on getting up to spindle speed and you finding out the E stop button doesn't work.
I concur with the Energized to Run methodology. Some manufacturers used an energized shutdown control system, but those were complex and less reliable. Lister has used a simple Energized to Run safety fuel control solenoid for decades.
dieselgman
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I use one of these to pull my fuel rack closed is there is a loss of power out if the generator. For example, if a belt broke, the device would shut the engine down due to loss of power. Same for over heat, separate circuit attached. If I had it to do over, I would have the magnet engage and hold a switch on. Thus when the engine lost power or speed, a big spring would pull the switch into the off position due to loss of power and thus the magnet holding it on would disengage. This system could easily pull a relay.
http://www.murcal.com/Catalog/Rack-Pullers/RP2309B-Push-Pull-Solenoid (http://www.murcal.com/Catalog/Rack-Pullers/RP2309B-Push-Pull-Solenoid)
Thanks for sharing this with me. It would be nice to cut the fuel off.
If I am understanding you correctly I should still install a Crompton voltage monitor in order to turn off the load in the quickest time. I can also use this to turn off the gas via a relay and a 12v transformer.
Having looked at the options on the Crompton website I believe the Crompton PVB-173/240 WITH AUXILIARY is my option. I can use this to close a relay that will control the entire load. I can also add to the load a 12volt transformer that will control your suggested solenoid. In the event of normal operation the Crompton monitor will energize the relay which will energize the load including the solenoid for the gas supply lever. In the event of undervoltage the Crompton will quickly disengage the relay, turn off all of the power which will in turn turn off the solenoid and close the gas valve. The only problem that I see is starting up the generator if the gas valve is closed. I might be able to install a timer relay that will energize the solenoid with 12volts from the battery for 5 minutes when I am starting the generator. I will just have to flip a switch to start the timer on the relay.
Thanks,