Mamimili wrote:I had a better idea, take a look at the Lenco Lovers website as someone must have answered the frequency question.
Yup!
Mamimili wrote:For frequency, they suggest a simple mechanical answer - turn down the tapered spindle by 20%.
There was a guy in Arizona who tried this with initial success but the temper of the metal was lost (if I understood correctly) in long term use.
Mamimili wrote:However, i still think my first idea is worth a try, look at his spindle measurements for 33 and 45 rpm on both shafts, it must be possible to adjust (sounds better than bend?) the idler wheel arm to run on the correct diameter for the required speed.
As pictured in LL the 50hz shaft is larger than the 60hz. If there is a point where the 50hz and 60hz shafts share the same diameter for 33.3rpm, then there's a chance for a 50hz motor to work in a 60hz environment.....although the 16 rpm indentation towards the end of the shaft bothers me plus the versatility of continously variable speed of a Lenco is lost.
Mamimili wrote:My only worry now is if it's as simple as i think, why hasn't anyone done it this way
Ditto
A frequency converter is basically a clean sine wave generator driving a low distortion power amp. Years ago I did an experiment on a Hurst motor in my Merrill modified AR turntable. I hooked a sine wave generator (set @ 60HZ) to a bridged Hafler DH120 and and drove the motor from the speaker output, it worked!!! But as you can see, it is an expensive proposition. The only reason I ditched the project was because my TD124II still had significantly better pitch stability.
It is very possible to do this on an idler drive motor. For ex: 50hz Lenco set the motor to 110/120V and the generator to 50hz, increase the output of the generator until the motor starts running from a 100W amp's output terminal. Those of you adept with solid state (I'm not) can experiment. Build a 100-200W IC amp with a built-in 50hz/60hz oscillator, or make it variable from 30hz to 100hz so that speed is electronically controlled.
je