Pulley size

[NoSpark]

According to my calculations, with 23" flywheels at 650 rpm and an 1800 rpm generator I would need an 8.X" size pulley on the generator and not the 11.x" I got with it. The engine seems to be turning really fast to get 60 hz. But I don't have a tach to see what the speed of the engine is. What size gen pulley should I have?

[carlb23]

take a look at this link, you're answers are there.

http://listerengine.com/smf/index.php?topic=3897.0

[oliver90owner]

Circumference of a circle is directly proportional to the diameter.  Double the diameter, double the circumference, etc.

Therefore divide the diameters and mutiply by 1800 or 650 as appropriate.

So : 23/11.x*650 = rpm of genny

or

11.x/23*1800 will be the engine speed at 1800

Looks about 850 rpm - what flywheels do you have?

Regards, RAB

[xyzer]

NoSpark,
You should have the 8.x generator pully for a 6/1 @ 650 rpm. The 11.x pulley will give you 850rpm like RAB says. You have an overspeed condition to achieve 60hz. Kinda unsafe with the 23" wheels! You need the smaller generator pulley or a set of 8/1 flywheels.
Dave

[ronmar]

What Dave said.  DON't run the 23" wheels above 650 RPM.  Flywheel explosions are not a pretty thing.

[NoSpark]

Ever have those hunches you just ignore until its to late. I knew that I needed an 8" pulley and it was supposed to be an 8" pulley. I looked at the pulley a few times and thought "man, Ive got to measure that thing" I started it up last night, It ran so good, hardly any vibration at all, its not even bolted down yet. I plugged in the Killawatt and only 52 hz so I started cranking up the speed, when I got to 60 hz the frame was hopping like a rabbit  and I shut it down 3 feet from where I started. That's when I finally measured the pulley  . So here I am again asking a question I already know the answers to. Hopefully tomorrow I can get a hold of the seller and get this thing swapped. Thanks

[wrightkiller]

NoSpark : Who did you buy it from? 

[NoSpark]

I did the calculations myself and yeah I had it going 850 rpm! I'm glad it wasn't 1000, with no cooling system yet I wouldn't have run it long anyways. Seems someone else got my 8" pulley and I got their 11" pulley. An honest mistake, should have the right one in a day or two. Hopefully no damage done. One thing though, I used the belt I had to layout the ST bolt slots, oh well.

[collectors]

According to my calculations, with 23" flywheels at 650 rpm and an 1800 rpm generator I would need an 8.X" size pulley on the generator and not the 11.x" I got with it. The engine seems to be turning really fast to get 60 hz. But I don't have a tach to see what the speed of the engine is. What size gen pulley should I have?

Hi, this calculator link might be of use for you if ever needed. http://metestsite.co.uk/pully-and-inch-calculater.html