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Post by chocogeek on Sept 12, 2008 20:03:16 GMT -5
I am firing up a Spectra 40 (the big one) for the first time and it seems to rotate awfully fast. I roughly calculate 200-300 RPM. If I put a piece of tape on the bowl and count the rotations it is about 4-5 per second.
This is rotating so fast that it throws material against the walls and up onto the inside of the lid and then leaks out the lid and splatters onto nearby walls. You must have the lid on or you will get a huge mess. I am just breaking it in with sugar and vegetable oil for now and the consistency is similar to chocolate. I am wondering if this speed is normal. Does anyone have experience with this or exact specs on RPM so I can tell if this is normal?
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Post by chocogeek on Sept 13, 2008 1:08:38 GMT -5
OK, I did a more accurate measurement and got 260 RPM. I am thinking this is how fast this thing is supposed to run. It may behave better with a full load, and right now I don't have much in it. Anyone else using the Spectra 40?
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Post by kellymon on Sept 14, 2008 16:04:42 GMT -5
I don't have a Spectra 40, that does sound way fast.... A load shouldn't slow it noticably unless the belt is slipping, AC motors run at a specific speed +- a few percent based on the number of poles and the frequency of the electricity. Or else they overload..... Is it possible that your unit was designed for 50hz (common in some countries) instead of the 60 hz the USA uses? That would make it run about 17% faster. Otherwise, it would have to be a pully ratio issue. Keep us posted please. robert
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Post by chocogeek on Sept 15, 2008 21:59:43 GMT -5
Thanks Robert, I think you are correct. The unit is built for use in India where the frequency of the line is 50 hz. and it is an induction motor so the frequency of the line would affect it like you suggest. If you are correct that the difference is 17% and with my estimate of 260 rpm now, that would suggest it was built to rotate at about 215 rpm.
I thought about changing the pulley too, but the small pulley on the motor is already quite small and the big pulley (sheave) attached to the base could be changed out if I could find a replacement. What I have found online so far is fairly expensive and could be hard to retrofit. Will keep you posted if I decide to change it out.
For now I think I will use it as is and keep close watch on it for the first batch, check motor temp, smell and sounds for any problems.
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Post by kellymon on Sept 17, 2008 17:29:06 GMT -5
Actually, I mispoke a bit.... 50hz is 17 % slower than 60hz, but what concerns you is that 60hz is actually 20hz faster than 50hz...make sense? So actually it would be turning at 208 rpm if it was in India There are small variable frequency drives available but you would need to change your motor to a 3 phase motor. Someplace like Automation Direct has units that will run on 120 volts single phase (household type power) and convert to 3 phase and you could easily run at half speed and anywhere in between. But the motor and VFD would probably cost about $300-$400 total so that's kinda expensive, but might be worth it in a commercial enterprize. Someplace like Graingers Supply, or McMaster Carr might have pully options that would work. Still, it doesn't seem like you should have to re-invent a machine you just bought...... Do keep us informed how it goes robert
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Post by jeffpzena on Feb 20, 2009 14:29:47 GMT -5
I have the same problem with my Spectra 40. It is set up for single phase 220 right now, but I'm open for changing anything to make this thing work right.
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Post by benvt on Jun 4, 2010 16:26:50 GMT -5
Has anyone fixed this? We finally moved up to our 40 and it does the same thing. New Spectra 40s come with a speed controller. Can you purchase the speed controller separately? Is the controller something you can buy at a hardware store or online? Any other solutions? I guess you could seal the top better, but I'd like to be able to run it open sometimes., and condensation may be troublesome.
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