[Tencubed]

Some time back a friend who is "sorta sharp" and right about things most of the time told me an automotive alternator will produce power regardless of which direction it is turned. Anyone know if this is correct?

If this is accurate it would make things a lot simpler for adding an alternator to some equipment.

I know there are counter-rotating alternators on some boat engines where the engine is designed to run in reverse direction for duel engine applications. These alternators would have the airflow blades on the pulley properly set to cool the alternator if it would produce the power.

Mike

 

[ranchkingron]

I have no idea TenC ?

But I have never heard of a counter rotating engine in any boat.

Most boats that have counter rotating props (to stop transom walk) are done thru the sterndrive not with the engine, with the exception of multi engine aircraft that in most cases have counter rotating props/engines as far as I know.

If what you have been told is right that would make adding one allot easier, but where would you get the reverse cooling fan for it ?

 

[Ingersoll444]

As far as I know a alt does not care what way it turns.

as for boats Ranchkingron. Ya... its pretty common in inboard boats with two engines to have one turn clockwise, and one anticlockwise

 

[m.jodrey]

But I have never heard of a counter rotating engine in any boat.

I know there are some marine engines that do counter rotate.
As to the alternator,I believe that is so,I have seen alternators on different applications mounted so they rotate "backwards" and they still charge.

 

[JRC0528]

Yup, electronically an alternator doesn't care what way it is turned since internally it produces AC which the diodes rectify to DC. Still, I'd want to take a look at the brushes to see if they are perpendicular to the commutator or angled to it. That wouldn't affect it's ability to generate power but it may affect brush life. As to the fan, as long as it draws air through the alternator properly you won't have any issues. As stated above, some marine applications use counter-rotating alternators with bi-directional fans. Keep in mind that the cooling capacity of your fan dictates the maximum power you can draw from the alternator; exceed it and you can expect the alternator to burn up in short order!

 

[Tencubed]

Thanks for the input. I owned a boat that had the counter-rotating engine for a short period of time. I know the counter-rotating alternators exist so there has to be pulleys out there somewhere. I just didn't know for sure if it had to be a special alternator. I could see no reason mechanically or electrically it would not work.

When I called the parts store this morning the lady that does a lot of my hunting for me just said "Oh good grief Mike! Where do you come up with this stuff? Give me a few hours." So maybe by this afternoon I'll have some part numbers for pulleys.

Mike

 

[Tractor-Holic]

The altenator I put on my SS-12 is a GM 10-SI from the 70's,and the way I have it mounted it spins "backwards" compared to how it would on the original pplication..'It charges fine and shows no sign of overheating,in fact the fan on it still puts out a healthy breeze even spinning the opposite way it should..the engine also blows some air on it as well..

I have read on other websites threads about building welders from altenators that mention the fan is spinning the wrong way,but no one has had any problems,and if anyone would it would be them,they are running the altenators unregulated at "full bore"..I sincerely doubt we would ever have any troubles with one on a tractor,that is only being used at less than half its rated output...

 

[ranchkingron]

Thanks for setting me straight guys, like I said I haven't heard or seen any myself but then again most of the boats here are not the most technically advanced around.

My Whaler has twins and the are the same except for the lower units which are reversed so the powerheads can be swapped between them, same goes for my buddy's Wellcraft with twin Chevy 350"s the only difference is the sterndrives ?

I'm glad you found out what you needed Mike and now it gives me some ideas.

 

[Tencubed]

Good to know about the alternators being spun backwards not heating up. I'll have to let the parts lady know as she is having trouble finding the "backwards" pulley as she called it. Maybe they don't bother to change the fan at all, I don't know.

We had one boat that had twin 225 Evenrudes on it. The only thing that was different on them was the props. One gearbox was run in what would have been reverse with a normal prop. I can see where it would be simple to do the same thing with outdrives. The boat we had twin inboards in had shaft drives. Should have kept that boat, all fiberglass with twin six cylinder Chevrolet engines and ran smooth as glass.

Now to start building the mounts for the son's Cub Cadet.

Thanks everyone, good to have a place to ask these questions.

Mike

 

[hankll]

I don't claim total knowledge of any engines that are designed to have PTO other than from the trans or "lower unit" in an outboard. All CCW prop action is accomplished through the trans as far as I 've ever been aware of. It is common for torquing of the power output to be counter balanced through CCW rotation of one prop and the other prop being "normal" and directing the prop wash against the center line of the boat. Normal prop being the port engine, and CCW prop being the starboard engine. Again, just in my experience, I've never known of this being done with a CCW rotating of the engine itself.

 

[Loremaster72]

They do make counter rotating engines. I knew of someone who was copying a design for a machine that had originally been built by a contractor in his shop (with his permission). It was a great starting point, so they built the entire machine to start durability testing and development with. When they fired it up, the machine spun backwards. It turned out the engine originally used (because it was sitting in the shop already) was a reverse rotation Jimmy Diesel! He had the nickname of "Wrongway" for a while after that. Since I heard about it from the man responsible, I'd say it did happen.

I also recall a rumor about a local sprint car racer who won a lot of races one year. They found was running a reverse rotation engine and banned that the next year. This could be totally urban legend.

I seem to recall hearing that serpentine belt alternators typically spin the opposite direction from V-belt drive alternators. I'm not sure if this is on GM vehicles, or more general. It could be altogether wrong, but it may be something to look into if you are trying to find a new fan piece.

 

[Tractor-Holic]

I'm not sure if the altenators used on serpentine belt drives rotate the opposite direction of a v-belt driven one,but I do know the water pump on a later model GM V8 turns the oposite way than the old v-belt types,because they are driven off the "back" side of the flat serpentine belt...

It is possible to run an alteanator off a v-belt the same way,if you get a special belt with a "V" on both sides...

I have seen counter-rotating Chvy 350's and 454's,and 318-360 Mopar V8's in older inboard boat applications...they were popular during the 60's and 70's more so than today,now they use gearboxes instead of making the engine run "backwards"..

 

[ranchkingron]

I don't claim total knowledge of any engines that are designed to have PTO other than from the trans or "lower unit" in an outboard. All CCW prop action is accomplished through the trans as far as I 've ever been aware of. It is common for torquing of the power output to be counter balanced through CCW rotation of one prop and the other prop being "normal" and directing the prop wash against the center line of the boat. Normal prop being the port engine, and CCW prop being the starboard engine. Again, just in my experience, I've never known of this being done with a CCW rotating of the engine itself.

Thanks Hank for proving to me that I'm nut crazy, because like you I've never seen one either.

But after asking and doing some research on it with my marina there are quite a few companies that use reverse rotation engines and I asked what the benefits are was told there really are none they work just as well as any other design.

 

[Tencubed]

Maybe I should have mentioned that I've not seen a counter-rotation boat engine for a number of years. Maybe should have said nothing about the source of my curiosity and not caused a problem.

Sorry about that.

Mike

 

[hankll]

Maybe I should have mentioned that I've not seen a counter-rotation boat engine for a number of years. Maybe should have said nothing about the source of my curiosity and not caused a problem.

Sorry about that.

Mike

Not a problem, news to me about CCW rotating engines......it proves I'm still alive- I just learned something new

 

[ranchkingron]

Not a problem, news to me about CCW rotating engines......it proves I'm still alive- I just learned something new

:ditto::ditto::ditto:

 

[mikeemc]

I'm an old boat engine guy , The Jimmy series can run left or right depending on how the main block is turned. The Gray marines too the use different cams. Some use the detroit , Peragone, or cone trannys to do the reversing . The alternator is Bi-drectional and generators are too by changeing the field wire. no such thing as reversing fans or pullies. some just use a fan extention houseing for air flow purposes , just a sheet metal band.

 

[Loremaster72]

Hey, it's always fun to have a thread that gives us "OF's" and "JOFIT's" a chance to ramble and relate stories of how stuff used to be done. Bonus points for anyone who can figure out the above abbreviations.

 

[mikeemc]

those are not in my 1921 Audels repair manuel.

But there is a Arens-Fox twin double (4 cylinder) piston pump driveing mechanisim. can you guess what it was used for ?

 

[kccraftswoman]

ooo ooo oooo i know i know the answer is and ariens fox fire truck they had the pump mounted on the front of the truck and some early ones were chain drive.raying:raying::050::050::bellyemot:bellyemot