Coverting Model 45 to two speed - $16 DIY Pulse Width Modulation Controller?

[jazzjourneyman]

Greetings!

I recently picked up a Hammond B2 and model 45 Leslie that had not been started in 25 years. Hammond oil and bit of patience got the B2 up running, zapping the scanner scanner resolved a motor boating issue, and I plan to install a TrekII percussion unit. I also want convert the Leslie 45 to two speed operation and have been reading up on the several PWM units designed for this purpose. Last night I found this on amazon and ordered one in for experimentation. https://www.amazon.com/SMAKN®-0-220V...eed+Controller


Have any of you folks tried this gadget, or something similar? Any thoughts on whether it should work, or not, and why? And do I risk damaging the motors simply by experimenting with this controller - or is monitoring motor temperature [to avoid overheating] the primary issue to keep in mind? All comments/advice welcomed and appreciated.

Cheers!!!

DT

I'm often referred to as a "renaissance man". Though in my case, I suspect it is due to my poor hygiene and penchant for wearing long dark filthy robes.

[JoeyB3]

Tried it....don't work.

The problem is torque. I was able to get a very nice, quiet, and smooth Chorale with this little unit. Motors stayed as cool as a cucumber too! But when trying to switch from fast to slow, or vise versa....it cant get the job done.

[jazzjourneyman]

Hi JoeyB3... thanks for your response! it's encouraging you could get a nice Chorale. How were you switching from slow to fast and back? Were you using the dial on the unit? If this unit can indeed do slow well, maybe there's still potential here. I was thinking the gadget would remain "preset" at an optimum setting for slow speed with its output going in to one side of a relay, and the other side of the relay receiving full line level voltage. So the relay when activated would toggle between providing the motors with the preset modulated "slow" voltage or the standard line level AC voltage. What do you think? Also, was it this same exact unit you tried?

[Drawbar Dave]

Benton Electronics does the best one AFAIK

[jazzjourneyman]

Hi Drawbar Dave! Yes, the Benton MTCLogic system looks excellent. Why do you like it better than the Hamptone?

[JoeyB3]

Hi JoeyB3... thanks for your response! it's encouraging you could get a nice Chorale. How were you switching from slow to fast and back? Were you using the dial on the unit? If this unit can indeed do slow well, maybe there's still potential here. I was thinking the gadget would remain "preset" at an optimum setting for slow speed with its output going in to one side of a relay, and the other side of the relay receiving full line level voltage. So the relay when activated would toggle between providing the motors with the preset modulated "slow" voltage or the standard line level AC voltage. What do you think? Also, was it this same exact unit you tried?

Alas - all of your ideas I have tried and resulted in failure. Yes....I tried this using the same type of regulator you refer to.

I attach below my simple schematic for this experiment. I used relays to switch between the full AC voltage and the adjusted voltage of the regulator. The problem, as I previously mentioned...is that after you achieve a nice Chorale speed by setting the knob on the voltage regulator....when you switch to Tremolo it's fine....however, when you go back down to Chorale...the drum (or horn) simply stops. You then have to "ramp up" the cheap voltage regulator to get the drum (or horn) again to move, and then back down to the desired chorale speed.

The cheap voltage regulator does a fine job of holding the drum (or horn) at the Chorale speed once you set it. But it cannot get to that speed without you nudging up the voltage on the regulator first.

I had a video of this posted on the FB group for Hammond techs....but I cannot seem to find it.

This is a novel idea that many of us have tried...it seems however that none of us believes the previous guy when he says it does not work!!!

[KC9UDX]

You don't get switching noise in your audio from this?

Someone added a light dimmer to a Leslie I have. I don't know what they were thinking. No matter how you adjust it, it's either full speed or stop.

[JoeyB3]

You don't get switching noise in your audio from this?

Someone added a light dimmer to a Leslie I have. I don't know what they were thinking. No matter how you adjust it, it's either full speed or stop.

Nope no noise - it was as quiet as a church mouse....it just didn't work the way I had hoped, LOL!!

[Jyvoipabo]

Last night I found this on amazon and ordered one in for experimentation. https://www.amazon.com/SMAKN®-0-220V...eed+Controller
[ATTACH=CONFIG]29536[/ATTACH]

This is not a frequency controler. This is a rudimentary dimmer with well known hysteresis problems.

Amazon say :

Answer:

Yes, this device can control the speed IF the motor is a universal type. Universal motors have brushes and field coils. Inductance motors cannot be reliably controlled with this device as speed is a function of frequency while in the universal motor, speed is a function of voltage.

It don't work with asynchronous motors, but you can use it with some workshop and household equipments.

This one seems to be better :
https://www.--------/itm/AC220V-Variable-Frequency-Drive-Single-Phrase-VFD-Speed-Controller-Inverter-zg/332591009849?epid=9016759619&hash=item4d6ff81039:g :1~YAAOSwqpha2AKv
This model is 230V and there are a lot of buttons on the front and can be so many problems to configure it, but i think it should work.

JP

[jazzjourneyman]

I received the controller yesterday and tested it tonight. So far the test results look very good. I wired the controller inline using a standard standard extension cord with both motors plugged into the 3 outlet pigtail. Like JoeyB, I was able to dial in a nice, smooth Chorale speed and let it run for a half an hour - motor temperature remained slightly warm - never not. Then I unplugged the extension cord and allowed both rotors to come to a compete stop. When I plugged it back in, both rotors immediately returned to a stable Chorale speed. So it seems logical that using a relay to switch between full line level AC for fast and regulated voltage for slow will work. I will post pics and video once this is confirmed.

That JoeyB and I did not have the same experience is likely because we were working with different iterations of a similar type of "cheap controller" technology. For whatever reason, the one I tested worked as I hoped it would [and yes I was surprised]. So if anyone else has a single speed Leslie, an adventurous spirit and an extra $16.66 to spend, please feel free to purchase this specific controller and see if you can replicate my results - and please report back here as I will as this project continues.

And Jyvoipabo... You are correct, it is not a frequency controller. It is a pulse width modulator which is a bit more sophisticated than a rudimentary dimmer. The amazon answer you cited was just an opinion written by an amazon user, not the manufacturer/vendor. I have no idea whether Leslie motors would be classified as inductance, universal, or asynchronous. I only know that so far, this controller works with the standard motors in my Leslie 45. Will this gadget offer a long term, cost effective solution to a common problem? I have no idea, but I plan to find out. Half the fun is the process of discovery... right?

[Jyvoipabo]

Hello,

I am curious to know what is inside.
If it looks like this :
https://www.amazon.com/uniquegoods-5.../dp/B00QLH8530
So it's a dimmer.
Otherwise I was wrong and i apologise.

Leslie motors are asynchronous with starting coil (Frager).
They work with dimmer but not properly.

JP

[JoeyB3]

I received the controller yesterday and tested it tonight. So far the test results look very good. I wired the controller inline using a standard standard extension cord with both motors plugged into the 3 outlet pigtail. Like JoeyB, I was able to dial in a nice, smooth Chorale speed and let it run for a half an hour - motor temperature remained slightly warm - never not. Then I unplugged the extension cord and allowed both rotors to come to a compete stop. When I plugged it back in, both rotors immediately returned to a stable Chorale speed. So it seems logical that using a relay to switch between full line level AC for fast and regulated voltage for slow will work. I will post pics and video once this is confirmed.

Yup - that was exactly the point where I thought I had a winner!!
Give it a shot, Jazz....if you are able to do multiple switchings back and forth between Tremolo and Chorale, please post a detailed video showing every aspect of your experiment. You will have succeeded where many (myself included) have failed. And you will have provided an substantial cost savings when compared to the Hamptone / MTC Logic / etc.

If you should be successful - then after that initial victory, the next hurdle would be stability over the long haul. Good luck!

[joecool240]

Other parameters to consider with this controller setup are 1) is chorale speed correct, and 2) is the slow to fast speed spin up time and fast to slow spin down time correct, especially on the bass rotor. A properly working Leslie with two speed motor stacks definitely has a "factory correct" sound for chorale speed and spin up/spin down time.

Joe

[KC9UDX]

If it's too quick that's a job that a simple microcontroller could solve.

[toomanytoyz]

Quick question: Can you vary the speed from fast to slow and back again using the speed control knob?
BTW, KC9UDX, I used to live two miles due east of you on Guthrie Rd.
Kurt K9KES