Start-o-matic relay sequency

[veggie]

Curious ....

On a genuine start-o-matic, how does the starting system know when to release the decompression lever to allow starting. ?   
I would assume the starting motor does not fight compression immediately.

[broncodriver99]

Not first hand experience here but from what I have read and youtube videos I believe the starting winding does have to overcome compression immediately. The videos I have seen you can hear the solenoid actuate the decompressor(removing it from under the valve lifter) and fuel rack(opening it) and then the flywheels start turning. There is another click that can be heard as the engine comes up to speed but I believe that is another relay/solenoid switching over from supplying starting current to the DC windings to pulling charging current from them and charging the battery. I believe it is either timed or orchestrated by monitoring the current the dc start winding is pulling. I believe you can also hear a relay energizing the output to the load once up to speed.

[Hugh Conway]

Here is a pdf of the start-o operation (hope it posts). I can't make out if the starter turns against compression. I've not attempted to get my start-o-matic system to operate, so removed the bits and use hand starting. With the COV as originally installed and set to high compression, it starts very easily, unlike my listeroid.
If I've done this incorrectly, and the pdf does not work, PM me, and I will attemptto email the file.
Cheers
Hugh

[Hugh Conway]

Just ran across a webpage that fully explains the startomatic operation. Looks like the starter DOES turn against compression.
The site explains general operation, starting sequence, and the refurbishing of a 5/1 start o gen set.

http://electrokinetica.org/d1/1/3.php

Cheers
Hugh

[veggie]

Thanks very much Hugh.
I was thinking about automating my starting process with a couple of DC linear actuators and an Arduino controller.
I was particularly interested in the timing of the compression release on a Startomatic. However, I cannot use the same starting sequence as an SOM since my starter will not overcome compression from a dead stop.
It has no trouble once the wheels are rotating, but the initial inertia combined with compression is too much.
So my plan would be to .... Open the rack ... allow say 5 seconds for the wheels to spin up ... then allow compression.
During shutdown the actuator would move to the decompress mode ready for the next start.

Some sort of rpm or generator output sensor would be used to confirm a successful start.

Oh.... so your SOM is not working ....  that must make you very angry.      In fact I bet you want to get rid of that thing.
I offer to drive from one province over and remove that malfunctioning SOM machine for you. No charge to cart it away.
Now .... where did I put my ferry schedule 

[Hugh Conway]

@ veggie Re the startomatic gear.........
I know you're having a vit of fun with this quote "Oh.... so your SOM is not working ....  that must make you very angry.     In fact I bet you want to get rid of that thing.
I offer to drive from one province over and remove that malfunctioning SOM machine for you. No charge to cart it away.
Now .... where did I put my ferry schedule."

Seriously, I can see that I will never get around to making it all work. Since it cost so much in the first place, don't want to give it away, but would consider selling it all except the engine, That one is in use.
I do have the control boxes, the solenoids, valve lifter, the 2.5 Kw gen head, even the belts. The unit was complete when I got it from Oiler in Denmark. Could ship if nccy.
Cheers
Hugh

[BruceM]

Methinks you may be wrong about normal SOM operation. On the SOM docs I studied before I built my own remote start Listeroid (not the document Hugh listed here), a single big solenoid controls rack closer and inserts a spring loaded spacer as valve lifter. I can see no point in having the valve lifter if the engine is started through compression, and Lister didn't add things unnecessary.

I concur with the Arduino and linear actuator approach as being a sound one.  There are some low side switching MOSFET boards you can use for solid state switches. If you'd like RPM sensing, you can use any inductive sensor near the spoked wheels for rpm sensing.  I used a Cherry brand hall effect sensor w/magnet proximity detector instead.  If you've got solid wheels, a hall sensor and some small glued on the hub magnets will do the job.

[Hugh Conway]

@ BruceM.........I always thought that the ex valve lifter was gotten out of the way after a few seconds of starter operation, as you say. The explanation in the link I provided does not indicate that, saying the starter turns against compression from the moment of energization. Seems counter-intuitive, doesn't it? I would think there was a bit of a delay before the solenoid is energized and then moves the lifter out of the way.
Cheers
Hugh

[BruceM]

Very odd indeed.  Perhaps someone with working SOM experience can fill us in on the hard facts.  The valve lifter makes no sense at all if the starter can crank through compression.

[mikenash]

Thanks very much Hugh.
I was thinking about automating my starting process with a couple of DC linear actuators and an Arduino controller.
I was particularly interested in the timing of the compression release on a Startomatic. However, I cannot use the same starting sequence as an SOM since my starter will not overcome compression from a dead stop.
It has no trouble once the wheels are rotating, but the initial inertia combined with compression is too much.
So my plan would be to .... Open the rack ... allow say 5 seconds for the wheels to spin up ... then allow compression.
During shutdown the actuator would move to the decompress mode ready for the next start.

Some sort of rpm or generator output sensor would be used to confirm a successful start.




Oh.... so your SOM is not working ....  that must make you very angry.      In fact I bet you want to get rid of that thing.
I offer to drive from one province over and remove that malfunctioning SOM machine for you. No charge to cart it away.
Now .... where did I put my ferry schedule 

Hey Veggie, Hugh and others

I don't know if this setup or its parts could make a contribution?  I bought it a while back.  I believe it to be a SOM unit re-housed in a more modern (maybe '70s) cabinet by a local electrical shop.  It was starting a Lister generator on a remote station here in NZ well into the '90s.  I bought it from a retired engineer who worked on the station at one time

Check out the pics if you like?  If you look carefully I think there are some "spares" in there too - coils?  I don't know if SOM bits are common across models - but I'm sure some of you guys will know

Cheers

[AdeV]

AIUI, the SOM system doesn't need the valve lifter; it's there in case you have to manually start the engine, and we know how difficult that can be without a run-up on the crank handle...

[38ac]

Well, I am certainly not an SOM expert. Matter of of fact I have never even seen a complete unit in person. However I have had several ex SOM CS type engines through the shop including my current build and all of them decompress the engine with the same solenoid and lever that operates the fuel rack? Here is a picture of the setup I have seen on 5 or 6 CS engines.

[Aberdonion]

I am a regular reader of this site but have only contributed once before. I grew up in Scotland without electricity until I was twelve then my dad installed a 5/1 SOM until we connected to the grid eight years later (1966).
I imported a 6/1 SOM from England a couple of years ago and intend to go off grid. I installed solar panels last year which are working fine but I am tied to the grid for three years having accepted an installation grant. I am working slowly on getting the engine to work then I will focus on the electrical side.

In answer to the question at hand the valve decompresion actuator is to stop the engine and close the fuel rack at the same time. On a manual start, one waits until some speed is worked up before releasing the valve decompression. On a battery start it has compression right away. - An Alberta Boy

[BruceM]

Thanks for the straight scoop, Alberdonion!
Interesting that Lister felt the rack was insufficient safety for shut down. Or perhaps early on there was doubt about the starter motor torque but lather they kept the valve lifter.