Overspeed

[veggie]

Perhaps something like this....
http://www.wescodirect.com/direct/Products/ProductListDetail.aspx?pik=37494&productId=37494

If the voltage from the Gen head drops below the preset 70-120 range, the relay opens (or closes ?)

veggie

Ooops ! I just noticed that they are $1300 each 

[veggie]

BINGO !

Monitors single phase voltage between 20 - 240 (user adjustable).
N/O and N/C relays.
Good price !

http://www.grainger.com/Grainger/ICM-Line-Voltage-Monitor-5KPX9?Pid=search

veggie

[mbryner]

Use a automatic gencontrol unit w/ overspeed protection.   Use a solenoid that holds the fuel rack open when activated, but is spring loaded so fuel supply is cut when not activated.   No power or fault or overspeed shuts engine down.

I tried Monicon controllers, but the starter relay output was faulty on 2 of them.   Now I'm ordering a controller from these guys:  http://www.gencontrol.co.uk/

Marcus

[veggie]

Marcus,
Regarding the controller you ordered....
How does the controller sense an overspeed situation ?
Do you need to add magnetic pick-ups to the flywheel ?

veggie

[mbryner]

veggie,

It senses off the frequency from the 120/240 VAC from the ST head.  Overspeed or underspeed will change the frequency and release the fuel solenoid.   It also means that if a belt breaks, the generator will shut down, too.   You can request specific over-/under-frequency setpoints (i.e. their recommended is 69 Hz and 45 Hz for US electrical systems).   I haven't quite ordered from them yet; still picking the options.   Don't know if it would work w/ just a magnetic flywheel pickup, but it might since it appears the electronics are just sensing the frequency.   I like the sensing off the ST head better anyway because your engine will shutdown if there is a fault anywhere between the flywheel and AC output.   Plug in a coolant sensor and oil pressure sensor and you have the whole thing taken care of for less than $200.

Marcus

[mbryner]

Wait, correction: it would work fine, but NOT w/ just a flywheel magnetic sensor.   The flywheel is rotating at 650 Hz (for a listeroid).   So you'd have to convert that to a number the engine controller could deal with, since it's expecting AC freq range not flywheel freq.   My bad.   Surely you all caught that already.....  

[Horsepoor]

Gentlemen,

Thank you all for you prompt and interesting replies. I think I found the less than $10 solution for under voltage (broken belt).

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400165010788&ssPageName=STRK:MEWNX:IT

And this plugs into an 11 pin socket (27E123)

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230561905984&ssPageName=STRK:MEWNX:IT

I can set this relay to lock open when receiving 120 - 240 VAC. If / when it looses VAC, the relay will close, thus activating my 12 VDC rack pulling shut down system. Now, this doesn't provide a solution for over voltage, but for $10 I take it for an engine shut down due to broken belt, rectifier burn out, AVR failure, etc. What I really like is this will sense no power to the water pump (120 VAC Grundfos Brute home hot water circulating pump) which should prevent most over heat situations.

Thank you for your posts, I am looking hard at the Grainer $79 sensor also.

Bruce

[veggie]

Just wondering....

When we overspeed an ST5 generator head, does it make more voltage? or just a higher frequency ? or both ?
If it make a higher voltage, then we can use the Grainger module.

veggie.

[Horsepoor]

Veggie,

It might depend if an AVR is included in the circuit. I suspect that if the AVR were involved, the device will try to raise or lower the voltage depending upon what the sensor sees. With a broken belt, the AVR will eventually not be able to maintain any voltage and the system will stop.

Now I wonder, if an engine is over speeding in the 1200-rpm area, might the AVR be able to hold the voltage down to a level, lower or below the upper trip limit. If the acceleration continues and the RPMs increase, something is going have a catastrophic failure (i.e. 2000 rpm), and the whole thing will come to a stop.

It would be nice to have an inexpensive frequency upper / lower limit trip device. I have looked but cannot find one cheap enough for my meager funds:  Installing a flywheel sensor for rpm is one option, but the expense has held me back.

Sure would like to find a reasonably priced frequency meter, that can measure frequency from the generator head and trip on 65 Hz or 55 Hz. Found one on the web in Sweden with trips at 45 Hz and 55 Hz but they don't make a 60 Hz version. Anyone know of a reasonably priced trip meter source please advise.

Bruce   

[vdubnut62]

You know, after some time spent scratching me head, I think I will incorporate some sort of deadman switch that can be activated from some distance away. Just in case Mr. Murphy makes an unscheduled appearance. It may be only a small nylon rope, but at least I won't have to get within grabbin' distance.
Ron

[mbryner]

veggie,

Both, unless AVR involved, then AVR will fail above a certain point.   Try running slow: you'll get both low voltage and low freq.   Since a standard ST head has just a simple bridge rectifier and multiple coils, so there's nothing to stop voltage from increasing.

[veggie]

veggie,

Both, unless AVR involved, then AVR will fail above a certain point.   Try running slow: you'll get both low voltage and low freq.   Since a standard ST head has just a simple bridge rectifier and multiple coils, so there's nothing to stop voltage from increasing.

Thanks Marcus
Good to know the grainger item will probably work  for applications using ST heads (without AVRs).

Veggie

[Lloyd]

An over / under AC voltage sensing relay (230 VAC), with an adjustable time delay, and powered by 12 VDC is what I seek. The 12 VDC is critical because if my generator system fails, I want to use the 12 VDC system to trip and power the shut down process. In a perfect world, a high / low frequency sensor would be nice, but the one I found was over $300 and not affordable. 

Anyone with a commercially available AC voltage-sensing relay with this criteria please post a link so I can buy a couple and integrate them into my Listeroid systems.

Bruce

Bruce, what is your budget? This link is $99.00 http://cgi.ebay.com/Deep-Sea-Controller-Manual-and-Auto-Start-Module-DSE701-/300555320245?pt=LH_DefaultDomain_0&hash=item45fa7e3bb5

OVERSPEED PROTECTION
The engine over speed trip setting can be calibrated at the rear of the module for 50Hz or 60Hz nominal operation (57Hz or 68Hz trip respectively).
During engine cranking and for the first 10 seconds after the engine starts running, all alarm conditions are suspended (overspeed is enabled) to allow the engine to reach its optimum running speed.

And it uses 12 volt control voltage.

Lloyd

[Horsepoor]

Lloyd,

Thank you. That is in my budget = 2 1/2 bails of "special" hay for wives arabian horse.

[veggie]

If the only features needed are over-speed and under-speed, you might consider something like this from Time-Mark controls.
If you contact them and get a price, please post it for us to see. There may be others who are interested in this.
Spec sheet below......

veggie