Adler 291 3 phase. Is it worth it?

[HamiltonMike]

Radrider,

I was looking for a walking foot machine for a week or two and after finding these machines on Kijiji I went and bought one. A day later I bought a second one. Apparently, I grabbed the last 2 of 3 he had left. I started searching online and ended up here in this discussion! 

I've been the manuals in some detail and have played with the machine extensively. I hope I can lend some knowledge on this 291. Mine is a 291-164062.

I've removed all cables, EFKA controller/motor, Knee switch and Start/Stop manual motor starter.

1. Single-phase to three-phase VFD and slowing the machine down.

 I had a small 1/2HP VFD -1 phase 240V in-3 phase 240V out kicking around in my garage. I connected the single phase to the VFD input and also connected the Efka controller (also single phase) to these lines from my breaker panel. The output of the VFD powered the motor. All fired up good. I also gave the machine an air supply to try the functions. What I found was rather interesting. Even though I slowed the motor to a crawl-like 5 Hz instead of the norma 60Hz- the Efka controller and clutch, with help from the positioner feedback, kept the motor at the set speed in the controller settings. Even though I feathered the pedal on it's slowest possible setting, the controller commanded the motor to the minimum speed that you can set the Efka control switches and dials to. When I turned the speed to 30Hz and then 60Hz the same thing happened. So I needed to move in a different direction. I bought a Reliable Motors SewQuiet 6000sm and made a speed reducer pulley in the garage. It gave me a 4:1 reduction. The minimum the new servo will run is 200RPM and so I end up with 50 stitches per minute on the machine. Pretty decent but I may attempt a bit slower in the future.

Here are some pics of homemade speed reduction pulley and new servo.

2. There are 4 air solenoid valves and 2 micro switches on board in the head. Valves are Foot Lift, Reverse, Cutter Engage and Speed compensation (I am not worrying myself with this last one). The 2 microswitches are also to do with the last function. These valves are 24VDC powered and so it would be easy (and planned) to make a small control panel to fire these functions without the controller. Currently, I'm finding the leatherwork I'm practicing on doesn't need the valves really so I'm doing things manually.

The Foot Lift is accomplished with a rod pushed into a slot in the of the mechanism that connects the Foot Lift air cylinder to the rest of the mechanical parts that head up into the head. See pic below. For now, I have a test rod shoved in there and it works. I plan to weld a steel plate on the rod and pad it (of course with a leather cover). It appears to be an insert and quarter-turn sort of assembly that goes into this slot.

Be sure when you lift the foot fully that the thread tension gets automatically released or else you can't pull finished parts out properly. I found a loose control arm in my machine that after tightening released the tension and worked great without having to release using the top lever near tensioners. 

Reverse, of course, is done with the lever upfront.

Thread cutter, if timed properly, can be engaged through a small hole in the top of the bed in the area under the elbow of the reverse lever. See pic below. I have not played much with this one as I seem just happy snipping the thread when done. This function is not air powered. It is a mechanical solenoid that engages the cutter in a slot milled in the main lower shaft.

3. Be aware that the German to English translation in the manuals leaves a lot to be desired and sometimes leads to confusing sentences. Persevere through the suffering! I've done a lot of the adjustments in the service manual after taking the timing belt off and hook assembly for cleaning thoroughly. I grew up with German-speaking parents and when looking at the translations I can come up with better wording than what's there.

4. Since the Servo I bought has an aux plug that energizes when you switch it on, I removed the original 6.3V lamp and placed a couple of LED tape light pieces right above the workspace and powered with a 12VDC power supply. Way more light than was produced by the old one and positioned out of the way. This old also dimmed when I slowed the motor down with the original VFD idea because it taps off of the motor winding.

5. Bobbins I have found to work are type M. Apparently there is a JUKI type M and a normal type M. This machine does not take the larger Juki type M. One problem I have yet to solve is that these type M bobbins do not mesh with the mechanism on the bobbin winder and therefore I can't wind properly-yet.

I think that those are the main points I wanted to share. I'm outta time for tonight.

Cheers.