50Hz vs. 60Hz

[Dave McGuire]

On Sep 25, 2009, at 6:10 AM, Sridhar Ayengar wrote:
>>>> matter.  The ones that we got drawings for and had duplicated were
>>>> worked from aluminum stock with quite a few processes to harden  
>>>> them and
>>>> form the drive surface so as not to eat the drive belt.  The  
>>>> shape of
>>>> the pulley causes the drive belt to ride in the center when  
>>>> properly
>>>> done, there are no "edges" to retain it.  If you have or can get
>>>
>>> Known as 'crowning', at least over here.
>>>
>>> It's surping the first time you see it, but the pulley is smaller in
>>> diameter at the edges than in the mdidle. The belt runs on the  
>>> largest
>>> diameter part -- and mves itself there when the pulleys turn. If you
>>> naively make a pulley with a smaller diamter in the middle (with  
>>> the idea
>>> being that he larger diameter edges will keep the belt in place),  
>>> the
>>> belt will fly off.
>>   It's called "crowning" here too.  How in blazes does that work?   
>> I've always wondered about it.
>
> The same way train wheels work.  Train wheels are of slightly  
> smaller diameter to the outside edge than they are on the inside  
> edge.  Makes the train sit between the rails rather than on them.   
> Along the same lines, the capstan sits in the middle of the belt  
> instead of on both outer edges.

   Umm.  Wow.  It never occurred to me to think of the capstan riding  
in the belt rather than the belt riding on the capstan.

            -Dave

-- 
Dave McGuire
Port Charlotte, FL