I've bit the bullet and bought a replacement motor for my Unimat 3. The original motor, despite being repaired a couple of times had a habit of tripping the mains, and of course Unimat motors are not continuously rated, so cannot be used for more than 8 minutes without rest. The lowest speed is 130rpm, a little too fast for some of the work that I intend to do. I do have a decent spare, but I wanted something better.
I found this one on eBay;
Another view of it fitted;
Speed range using one belt (no idler pulley) is a claimed 20 to 2400rpm, although I'm not sure if that's at the motor or spindle.
So, is it any good. Well, yes and no. It's nicely put together and smooth running, and adjusting the speed without swapping belts is nice (although swapping belts didn't bother me) as is the ability to work without worrying about the motor overheating. But, at low speed under heavy load the motor has a habit of 'pulsing' or stuttering, which is a nuisance when using profile tools. As I wanted a low speed motor for such work I'm unsure just how useful this motor is going to be, time will tell. This is the second motor that I've had from the seller, the first one displayed the same characteristics so I had it swapped (I should point out that the seller was extremely helpful). It may be that I only use it for general work and try to find another solution when using profile tools.
Paul.
Have you tried using the pullys to gear a higher motor speed to a lower spindle speed? This should help the motor stability, since it'll be running faster, and create with greater torque on the shaft, while still being 'slow', relatively speaking
ReplyDeleteNot yet, but the thought has crossed my mind. The U3 is currently packed away (it lives under the stairs and gets used on the dining table) but I'll be using it again soon.
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