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wky frmr
Member

CIH combine settings for corn

I have a Case IH 1640 with specialty rotor and I always have trouble running too much corn out the rotor early in the season before it dries down below 17%.  I usually set the transport vanes in slowest position and run the rotor at 360 to 380.  Should I slow it down more?  What works for the rest of you?  Thanks.

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5 Replies
Pupdaddy
Advisor

Re: CIH combine settings for corn

..I'm an old conventional combine operator..and slowing down the cylinder is only done to prevent kernal damage. If it was me..and I had to operate a specialty rotor on higher moisture corn..I think I would be wanting to whack it harder (by speeding it up) with the limited number of bars I have..or fill some of the grates with a filler bar so that it threshes harder. Only a guess here...you've operated a rotor longer than I have. I'm going to be interested in the replies..because I'm a thinking I might be looking at a rotor in my near future...

 

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Nebrfarmr
Veteran Advisor

Re: CIH combine settings for corn

We run a 1440, an IH rotary, but with a smaller diameter rotor, so our RPMs won't jive because yours will have a faster rasp bar speed at a given RPM, but here are a few rules of thumb:

 

The faster you run the rotor, the more capacity you have.  Running the rotor as fast as you can without grinding, and the concaves as open as possible and still shell the kernels gives you the most capacity through the rotor.

RPMs have the biggest influence if you are grinding corn.

Concave setting has the biggest influence if you aren't shelling it all.

Basically, speed up the rotor until you just start grinding corn, then back down.

Loosen the concave until you start leaving kernels, then snug it up a hair.

You don't want to see your cobs broken up into little pieces.  If that is the case, the concave is too tight.  You want to see as many whole cobs as possible, broken in half is OK, and you will probably never get it to not break just the tips off of some, but the bulk of your cobs should be whole or half cobs.

 

If corn is running over the sieve, more often than not, more air is better than less air.  In corn, we actually have the bottom sieve clear open, to get more air to the top sieve (keep in mind the 40 series had a weak fan, though).  We have yet to be ever docked for too much FM in a load, even from the bottom of the bin.

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wky frmr
Member

Re: CIH combine settings for corn

Well,  I started shelling today and it seems that whea is working best is slowing the rotor.  Kinda counterintuitive but seems to work.  Running the rotor at 310 rpm and getting good clean whole kernels in the tank.  Very little loss out the back, but more butt shelling in the head than I'd like.

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Pupdaddy
Advisor

Re: CIH combine settings for corn

I think it's kind of funny, none of us stopped to think maybe the bars on your rotor might be worn, LOL. I had a guy stop one time, and ask me how he could get his M2 Gleaner to pull more crop through. I asked him if it was spitting corn out the front of the combine. He said it was..and I immediately told him to buy some new cylinder bars..or turn the set he had around so they would wear on the back edge. He said he thought they were fine..until he asked me about the set I had laying on the floor. He thought they looked new..and I told him they were worn out. The very leading edge of a bar on the Gleaner is where the threshing occurs..and when it gets rounded, you turn them around and make the back side the leading edge until it wears down. The bars I had laying on the floor were very aggressive looking, until you look at the edges..and know a little about them. He had actually gone to a salvage yard..and bought a set of used bars for his combine. He didn't much like the idea of having to get a new set..and change them all again...LOL

 

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Nebrfarmr
Veteran Advisor

Re: CIH combine settings for corn

That might be about right.  We have the smaller rotor in our 1440 (less RPM for the same rasp bar speed) and I looked where we were last year, and it was about 380-400RPMs for the most part.  You have to go a little slower when the kernels are wetter, and more tender to prevent grinding.  When the corn starts coming in dryer, you can gradually up the RPM, and still not grind.

Keep the concaves open enough so it doesn't grind cobs, or you will lose capacity, especially over the sieves.

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