Onan Hp and year info

Picked up a Onan twin today for a very reasonable price that was sitting in the snow, looks to be ex millitary from the olive drab paint tag reads NSN 2805-00-788-8394 SR# 845614 Gen Data 6115-00-067-5186 2.25 Kw 1875 Rpm no generator attached to it just the engine, said to be running good, thawed it out and I see that since the exhaust pipeing was missing both exhaust valves stuck, but ignition and both intakes working, might even run (after doing exhausts) any info appreciated on this engine. thanks 'Al

Need more infomation onan made some many different models. Is this engine 2 cyl. oppose air cooled or 2cyl horizontal water cooled. Joseph Turrisi

Alan

I have an Onan 2 cyl. opposed 3 HP. on a genset. Military of course. Olive Drab. 120 VAC. 800 cycle. ?????????? Can't recall the RPM. I think it was 3600, not sure. Still in the water tight drop case. Runs GREAT. Have not found what this would have been used for, yet. When I get a chance, I will check the #s and let you know if they may be simular.

Jim

Engine is 2 cyl pancake air cooled probably about 180 lbs or so. Al

Alan i don't understand what you mean by pancake i have never heard that term used with onan. When you say pancake if you mean opposed than it sounds like a cck model. When i say opposed what i mean is that the clys. work against each other. If we are on the same track let me know as i have some info on the cck models which include the cck,ccka,cckb.

Joseph Turrisi

Joe: Sorry about the missunderstanding pancake is a commonly used term aroud here for an opposed cly arrangement( 1/2 of a volkswagon) I will E mail a couple of picts to you , I have found that regional differences in terminology, can confuse the issue. Yes it is air cooled. Thanks Al

Alan looks like you have a cck style however there are three different models the cck, ccka, cckb and i cannot tell which one you have. The difference between them is hp,rpm,compression ratio. The cck is 5.5 to 1 compression 2700 rpm and 12.9 bhp. The ccka is 7 to 1 compression 3600 rpm 16.5 bhp and the cckb is 7 to 1 compression 3900 rpm 20 bhp note that rpm listing is max rpm and bhp stands for brake horse power.This info came from Onan service manual (form # 927-0754). Since you have a model made for the military you are going to have trouble finding info for you unit. There is a gov. web site where you can get this info I think it is ntis.com but i am not sure. I have send the link on this board before so post a question and someone can tell you for sure. You should also contact Onan Corporation home office in Minneapolis, MN the # is 1-800-888-onan. If you call onan be ready for the run around. When you tell them this is a military engine they will tell you no info is availble because the have their head stuck you know were. It took me two months to get info on my military engine I talk to some guy at the home office but can't remenber his name your local dealer will be no help at all. These are well built engines and last forever I have one on a welder generator that was built when onan was owned by studabaker runs like a top and has never been gone through but beaware parts are expensive i hope this helps you good luck.

Joseph Turrisi

That's (www.ntis.gov). National Technical Information Service in Springfield, VA. I think their 800 number is on the website. If the unit has Technical Manual (TM) or Field Manual (FM) number on a tag then NTIS can usually provide a copy of the manual.

Joe: thanks for the info will get hold of the people when I get back from up north. Have to go to Wainwright(West of Barrow) monday and will be gone for about a week. work calls, the tag on the engine says 1800 RPM 24VDC 2250 W, 120 AC 1875W- got to studying the tag a little closer this time, had a bad overspray problem when it was overhauled in 82.thanks Al

Charlie: no FM or TM numbers just NSN and Gen data numbers as I told Joe will call them when I get back from up north, the site is sort of closed on the weekends from the looks of it, keeps telling me to come back when they are open on monday. Thanks Al

I think those 800 cycle units were for some military electronic equipment. 800 cycle transformers are smaller and lighter for the same amount of power as 60 cycle devices.

Russ: No 800 cycle on the tag just 120 Ac , 60 cycle single phase, and 24 dc, speed 1800 RPM. this seems really slow but thats what the tag says, the same as the older M800 Kohlers with the B&S motors. Should run forever at that speed. Al

I may have got my response in the wrong place. I was refering to Jim Tremble's response about an engine he has.

1800 RPM is quite common for generators that are designed to run continously. Some motorhome generators are manufactured for 1800 RPM to reduce the noise level as compared to the 3600 RPM types. I like them all!

I have three servo motors that I picked up in the 60's when I was going to an electronics school in Chicago. They were used to sight guns on a ship, I believe. If my information gets more than a month old every thing gets a little "fuzzy" but I know two of them were the same and one that went in between the two was called a differential generator.

These are about 2" in diameter and about 5" long with a small gear on the shaft. They have a tag that has (I think) 400 cycles, so some where there had to be a generator that produced 400 cycles.

These little guys are quite interesting. The "moma" and the "popa" are very simular to the TV antenna rotator. You set one for 120 degrees and the other one goes to 120 degrees and stops. If you put the differential generator between them and set it for + or - 10 degrees and set the first for 120 degrees the other will go to 130 or 110 + or - respectfully. I think they used the differential generator to compensate for wind. If there is an OLD Navy man out there, maybe you can tell how it worked.

I haven't looked at these for probably three or four years. The talk of 800 cylcles joged my memory and now a days it takes a pretty good jog.

Haveing fun just gaining knowledge here with Harry.

"DELCO DON"

Guys may have found the mfg date on the top of the engine hidden under the intake manifold was a set of numbers cast into a tag looking affair that read 8-11-65 if its like old engines this could be the block casting date? bore is 3 1/4 stroke 3 . Al

I have manuals for the Onan OTC-33B, 12 volt 2000 watt and OTC 59R-2, 115 volt 1500 watt, 800 cycles AC --28 volt 500 watt DC, and is shown mounted on a, 2 wheeled, wheel barrow type cart. and is listed as 5.2 HP.

Both are 2 cylinder opposed (pancake) air cooled. The OTC-33B Manual says War Department on the cover, and has wiring diagrams dated 1942. It shows the neat "drop case", and auxiliary fuel tank in it's own case. The panel has 10 plug type recepticals for battery charging leads and one set of wing nut type terminals for starting and high rate charging. No HP rating is listed. The OTC 59R-2 manual has no date, but I believe it is also military, the cover is typical of other older Onan manuals.

It seems that the Onan company is a not a real good place to go for information. Some time ago I made reqeusts for some history and general information about different models, but got no reponse at all. Phooey on them. "> Maybe if someone could send them a copy (don't look at me) of this and a few other Onan threads, they might get a better idea of how important some of the "outdated equipment" requests are to us and customer relations in general.

Those are not exactly a "servo", probably more like a "selsen". A selsen has a three phase field, or stator winding, and a single phase armatuer.

If you connect the three phase fields/stators together between each unit, terminal one to terminal one and so on, and connect the single phase armatuers together matching the terminal designations as before, and apply the rated volage and frequency to the armatuer leads, then when you turn the shaft of one device, the other device will follow. If the connections are wrong, when you turn one unit, the other unit may turn in the opposite direction.

The third device is a differential selsen unit. It has three phase windings on both the field/stator and the armatuer windings. When you rotate this device, it changes the phase relationships between the field/stator windings of the two selsens connected to it, causing the original selsens positions to change relative to each other as you stated. This allows you to correct, or modify the positional relationship between the two units.

We used these "selsens" to transmit the rotation of a pipe line sized liquid flow meter in the field some distance to the totalizer in a control room. This was done back before the advent of electronic pulsers and up/down counters. The ones we used operated on 60 cycle, 110 V AC instead of 400 Cycle AC.

You could, assuming you had a source of 400 cycle AC at the correct voltage, attach one unit to an engine crankshaft, or camshaft, and use the other unit to drive a remote tachometer. I am not sure why one might want to do that, but that was the only application I could think of that fits in with the discussion of old engines and generators.

On the other hand, you could tinker around a bit and if you drove the armatuer and excited the armature with some direct current, you would get three phase power from the stator windings. Of course because of the size of these devices you wouldn't get much power from them. You would have to determine how mch DC voltage you could safely apply to the armatuer windings without burning them up. The field/stator windings would probably take care of themselves.

The best applcation for these units would be to attach a wind vane to one unit outside, and a pointer to the other unit inside the house to indicate which direction the wind was blowing.

These units can be operated on 60 cycle AC in this manner, but at a much lower voltage than they are normally rated at. I am not sure, but it seems that a 115 VAC 400 cycle unit will operate on 24 VAC at 60 cycles and still have enough power to follow, or track each other driving a pointer, without burning the windings up.

Now if you could only reach down and turn the inside unit pointer in the house in some direction and make the wind outside blow in the same direction, you would really have something big going on there {

Alan I still think you hace a cck series engine. You should post the pictures that you sent me here for every one to see. I looked in my service manual and the cck series engines have a 3.250 bore and 3.000 stroke also is this a cast iron engine. Joseph Turrisi

Russ;

My memory was fuzzy in some areas and others it was correct.

The frequency thing is what got me to remembering them. I figured the high frequency must have made them more stable. I bought them from a army surplus store and they said to hook them in series with a 100 watt light bulb to make them work. The 60 cycle current made them very jerky when you went to move one, the other would lag for a little bit and then kind of jerk into place.

I have never run across a high frequency generator and with the talk of military "stuff", I just wandered if any one had ever seen a 400 cycle unit?

After climbing into my shop attic I could only find two differential generators. The lable says: General Electric - selsyn differential generator - Model 2J1H1 57.5 57.5 V 400 cy - Made by Electomatic Typwriters Inc. Division of IBM Corp.

Could these have been used in Teletype machines instead of gun sites? Heck I don't even know what I have. When I bought them they were cute and cheap. I had given thought to makeing a wind direction indicator but I never got "A round to it".

"DELCO DON"

Don, I think the purpose of having the 100 watt lamp in series was to limit the current through the windings. Also the 57.5 volt rating is indicative of the thinking on the subject. Several articles I read years back suggested operating 400 cycle selsens off a lower voltage 60 cycle power source such as through a transformer. The resistance of a light bulb changes significantly with the applied voltage, or in the case of the load of the selsen connected to it.

This might explain the erratic operation of the selsen as you observed. The bulb presents a low resistance when dim and a high resistance when bright. So if the selsen used more or less power depending if it was loaded or not, I would expect the light bulb to vary in brightness. There is probably a lot more to this than I know anything about.

I played around with a number of the older teletype machines like the Teletype Corporation model 15 and 19 machines. These had either a standard 110 volt, 60 cycle AC motor, or some had a universal motor with a govornor. A tuning fork was included for setting the correct motor speed. You sighted through a narrow opening or slit at the open end of the tuning fork and looked at a series of alternating stripes painted on the outside of the governor housing that rotated with the motor. When the stripes appeared to stand still, the motor was at the correct speed. The universal motor would operate off a DC battery, or when the AC power supply was erratic and still run at the correct speed. Maintaining the correct speed was necessary to keep the teletype in syncronism with the other teletypes on the loop.

As for syncros, or selsens themselves, they might have been used in some type of a teletype unit, but I am not familiar with this application.

I have seen quite a few 400 cycle units when I was in the Air Force around aircraft. We had 400 cycle busses in the field maintenance shops where we tested and repaired aircraft radios. These were usually some sort of a seperate motor/generator unit to change 60 cycle to 400 cycle, etc.

They called them an inverter in the aircraft where the input was usually 28 volts DC and the output was 115 VAC, 400 cycles. Some of the aircraft had what was called a Sundstrand drive that got its power directly from the aircraft engines at varying speeds, which drove a 400 cycle alternator at a constant speed. With the weight of all this stuff, it was a wonder the aircraft ever got off the ground.

Its kind of neat hashing these things out with you guys, because I am always learning something new from someone.