Lower Rotor Pulley for Upper Horns

[theseacowexists]

If I use a motor stack with a pulley meant for a lower rotor/drum for running horns, will it affect the tremolo speed of the horn? I'm using said set up for the horns I've added to my 130, and it sounds like the horn is running at about half the speed of the lower drum when on tremolo. Chorale speed is just fine, as are the acceleration and deceleration times. Should I change the pulley for the typical three-step pulley for upper motors?

FWIW the horn spins freely with belt off. Also, the tensioner pulley is a screen door roller that seems to spin freely enough as well.

[joecool240]

Using a lower drum pulley for the top horn will definitely change the speed. The lower pulley is bigger than any of the three positions on the factory top pulley.

TREK II products has the correct pulleys.

https://trekii.com/leslie-pulleys-60hz.html

Joe

[theseacowexists]

Thanks Joe. I've got one on the way. The other thought I had was to remove the idler, widen the hole in the shelf for the motor, and shift the motor so that it is set up like the lower motor and rotor. This probably still wouldn't bring the horn up to speed until I get the correct pulley, would it?

[joecool240]

Moving the upper motor will not change horn speed.

What model Leslie do you have?

Joe

[clem]

If the pulley on the motor is larger than it should be wouldn't that make the horn spin faster instead of slower? I used a lower stack on a horn I added to a 120 once and really couldn't tell much difference in the speed. I do remember that tension was critical. Too loose AND too tight would both make the horn slow down.

[theseacowexists]

If the pulley on the motor is larger than it should be wouldn't that make the horn spin faster instead of slower? I used a lower stack on a horn I added to a 120 once and really couldn't tell much difference in the speed. I do remember that tension was critical. Too loose AND too tight would both make the horn slow down.

That's what I thought too. I wanted to try moving the motor to eliminate the screen door tensioner in case that is what is slowing down the horn. Is there a way to measure the RPM of the fast motor itself? I should probably rule out the motor being the problem too.

It's formerly a Leslie 130 with the stationary tweeter removed. I built the shelf for the horns and it uses a motor stack that appears to have been taken out a spinet. I replaced the spring and washers on the slow motor with the appropriate ones from TWG.

[clem]

My motor stack came from a 110 that was trashed. I eliminated the tensioner and just used the slotted bracket that was used in the 110 for tightening and even used the belt from the lower unit. Once I got the tension right I don't ever remember having any problems with it. I used it in a rock band for several years. Still have it actually...and I'll bet it still works.

I should probably rule out the motor being the problem too.

That is a good idea. It could very well be dragging. They're easy to free up.

[alpine]

These are shaded pole induction motors and assuming the bearings are OK and the motor free running, the speed will be correct for the motor. I too am using an ex-T500 motor stack on my FrankenLeslie. It came with the single motor pulley. I'm in the UK and rather than getting the trek II triple pulley, with the silly charges for post to the UK (not Trek's fault!), I found an Ebay UK seller who will machine Tufnol (SRBF) pulleys for around $7 each to any size I want. I bought a couple from him to play with, with centres to clear the 8-32 UNC screw. With a longer screw I have clamped up the pulleys together and can now play to get the speed I want. I would suggest you retain your idler pulley since the longer belt then allows for an amount of misalignment of the pulley stack with the rotor pulley.

[clem]

theseacowexists...I watched the you tube of your horns spinning. Your belt looks pretty tight and your horn does seem to be spinning too slowly. When I got mine to where the horn was spinning as it should you could actually see a little droop in the belt. I don't know if tightening put an extra load on the motor or what but mine wouldn't get up to speed if the belt was too tight. If I loosened it just a little it took right off.

[theseacowexists]

I've ruled out the motor. I widened the opening in the shelf so that I could adjust the motor stack back and forth. With and without the idler, the fast motor comes up to full speed! Now it seems that the issue is getting the tension on the belt correct so that I get tremolo and chorale, because when I switch to chorale, it seems that even the slightest amount of tension from the belt onto the motor pulley stops the pulley from spinning altogether. The slow motor is working and engaging the O-ring. Now that I'm typing this, I'm thinking I'm going to need to adjust the slow motor's contact with the O-ring, aren't I?

[clem]

Could very well be the problem. I think you're on the right track. Just needs a little trial and error and minor tweaking. I used to spray contact cleaner on a cloth and hold it against the oring once I had it adjusted in case I'd gotten some oil on it.

[theseacowexists]

That's exactly what it needed. It now works as Don intended:

https://www.youtube.com/watch?v=cLemVor_fyc

Sorry for the poor room lighting! I'll do a better video soon enough.

I ended up replacing the screen door roller with one that has a springy arm. Maybe the original was placing too much tension on it? I think the real problem was that the motors were too close to the horns by about an inch.

I still have the three-step pulley on order, so I'll have to try that next and see how it works. I gotta say though, I'm quite happy with how it's turned out so far. Thank you for all your input!

[clem]

Cool. Glad you got it worked out. I really enjoyed my modified 120.