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Author Topic: Rebuilding Strong Platter Motors James Ness Film Handler Posts: 47 From: Houston, TX, USA Registered: Jan 2008 posted 07-25-2009 06:30 PM                        I wanted to read the tutorial on this in the 'Tips' section, but everything in there seems to be down. Does anyone have this information saved?  |  IP: Logged Adam Martin I'm not even gonna point out the irony. Posts: 3686 From: Dallas, TX Registered: Nov 2000 posted 07-25-2009 06:34 PM                     Define "down". The document appears to be working fine.  |  IP: Logged James Ness Film Handler Posts: 47 From: Houston, TX, USA Registered: Jan 2008 posted 07-25-2009 06:40 PM                        I was getting a 404 page not found error on all browsers. They work now though, that was strange. My bad!  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 07-25-2009 11:26 PM                     Yep, just did two more motors this week with gone brushes ... Let me add an addendum on this above tip that I made for Film-Tech on platter motor replacing: AMTEK/Lamb have now used a different field winding procedure that, on a motor rebuild that I posted back in 2005 which shows using the smaller sleeve on the motor shaft, it will requre the usage of the 1/2" sleeve since this modified winding makes the motor run a bit slower, thus this larger sleeve is needed to compensate for the slower turing motor. thx-Monte  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 07-26-2009 08:01 AM                        The hardest part of the "procedure" is getting the excess parts off of the new motor. I use a bandsaw, but a hacksaw works as well. You make a saw kerf at just the right place, put a flat blade screwdriver in it and twist; thus releasing the unwanted and "sawn" part. Louis  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 07-26-2009 08:40 AM                     Monte, I think there has also been a change in the brushes as well. Just clening up the armature and installing new brushes causes the motor to run the same way a new one does... slower and with less torque. There's more to the problem than just the field winding. Mark  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 07-26-2009 09:12 PM                       The brushes have to be run-in, Monte. Before installing, hook the motor up to a makeup table and run that sum bitch wide open for about an hour or two. Then it'll run faster.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 07-26-2009 11:30 PM                     What I usually do - after putting it back on the tower: I plug the MUT in and let 'er rip for a good while to get them brushes seated to the 'com'. I also leave the back off so I can actually see how the brushes are going and also this lets the air flow from the front impeller be unobstructed when I run the motor at full rip. Tim, still play your banjo? I bet you're good at it... -Monte  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 07-27-2009 09:35 AM                       I wish. No, I haven't had the ol' banjo out for some time (I think my wife even sold it). The strings were too close together on the neck and I could never get my fat fingers to mash down on just one string at a time. I'd always end up pushing one string against a fret just fine, but dull the adjacent strings because my fingers were wider than the distance between them. They say there are banjers with wider necks, but I never saw one. I can't see how anyone could play a mandolin.. their strings are closer together yet! So, I'll just have to remain impressed by anyone who can play a musical instrument. I did get me a harmonica a few weeks ago... don't really know why. The jury's still out on whether I will follow through on that one.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 07-27-2009 02:14 PM                     (not to drift off-topic) I've been in music since early grade school-it's like golf: a relaxing hobby to have-you're own paradise of sorts. Harmonica's are fun to play as well. Just take some time to get used to finding the intervals and making them work when you inhale and exhale along with using the tongue armature. Back on topic - I had help from another tech on how to do these platter motor retrofits - anything to do to go past having to get parts from the factory..in saving the dough. -Monte  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 07-27-2009 03:53 PM                     quote: Tim Reed run that sum bitch wide open for about an hour or two. Then it'll run faster. Actually the instructions that come (or at least one time came with) with the new brushes tell you NOT to do that. They tell you specifically to run it in at a lower speed for the first few hours then gradually increase the speed as the new brushs seat. The reason for this is simple in that the contact area on a new brush is not only smaller but it is also probably uneven if the armature is at all grooved... which they usually are to some extent. The unseated brush just can't transfer as high of current as the motor would draw wide open. Another way to seat the brushes almost immediately is to cut garnet cloth in strips just slightly narrower than the armature and run it back and forth under the brush. The brush will then take on a contour much more like the armature itself. You should still run it in slower but it will seat properly much faster. If you talk to the tech guys at Amtek they will tell you much the same... Mark  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 07-27-2009 05:56 PM                        We assemble, clamp in a vice and run at fairly low speed as Mark describes. At some point the pitch of the brush whine will increase, TWICE. You are now finished. Louis  |  IP: Logged Randy Bowden Expert Film Handler Posts: 146 From: Portland, OR, USA Registered: Aug 2000 posted 07-31-2009 06:26 PM                     I've been doing these for AMC for a little while now. I replace the brushes, armature, bearings, and tires. After all that it's pretty much like a new motor. I run mine in at about 40% of variac full speed.  |  IP: Logged Andy Bajew Expert Film Handler Posts: 136 From: Bellaire, Texas Registered: Jun 2009 posted 08-01-2009 01:50 AM                     quote: James Ness I was getting a 404 page not found error on all browsers. That's the Drafthouse for you, James.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-01-2009 05:56 PM                     Randy, Non need to even replace most armatures unless you're rebuilding these on location... just take a fine cut or two with an extremely sharp small round nosed cutting tool on the lathe. They work like new and will last as long as film does... Mark  |  IP: Logged

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