|May 24, 2006, 04:45 AM|
Tektronix Phasor 740 Laser Printer Teardown
A few months ago, we got several new Color Laser printers in at work. They replaced a couple old-school units that were about 8 years old, and had seen the end of their useful life. They were going to throw the printers away, so I grabbed them and took them home to tear down for parts. The two printers were an HP Color Laser and a Tektronix Color Laser. Man, these things are real beasts! They each weigh a little over 100 pounds, so it is quite a strain to lift one up onto a table to work on it!
I was cleaning the garage today, so I decided to tear down the Tektronix printer. I had heard before that there were a couple nice brushless motors inside with 50mm stators! I brought my camera down to the garage and tore into the puppy and documented my teardown.
First, here is a photo of the unit with a close-p of the control panel. It is a Tektronix Phaser 740 model.
The back side of the unit had a removable panel, so I popped out the 6-7 screws that held it on and pulled off the cover. Here is what I found inside.
There they were! The two 50mm brushless motors I had heard about! Each one was held into place with 4 screws, so I unplugged the wiring harnesses, took out the 4 screws, and pulled out the motors. Here is the first one I took out.
The circuit board is about 4.5" long by 2.25" wide. The outer can of the motor is about 2.4" in diameter (61mm) as you can see in the photo below.
After I pulled out the second motor, I noticed that they were a little different. The second motor was only about 3/4 the thickness of the first one. Here is a photo showing the two motors side by side.
I started wondering if there were any more useable parts inside this thing, so I started pulling the rest of the printer apart. I figured that the motherboard and controller boards inside this thing might bring some mone on eBay, so I started pulling all the circuit boards out as well. I pulled the rear cover off that covered up the motherboard, and look what I found.
Yep, that's right, there was another 50mm brushless motor back behind the motherboard. There was also a couple nice ball bearing cooling fans in the way, so I pulled out the fans and the motherboard to gain access to the 3rd motor. Here is is after removing the other parts.
Now the big question, was it one of the smaller ones, or one of the larger ones. After I got it out, I was happy to see that it was a reverse rotation version of the larger motor.
After I got that motor out, I remembered hearing somewhere that there was another brushless motor up in the top that held the spinning mirror for the laser head. I took the top section off and flipped it over and sure enough, it looked like there was a brushless motor in there at the end of a ribbon cable.
I quickly pulled out the screws holding the aluminum plate in place and flipped it over and there was indeed another brushless motor to be found!
I then moved on to the input feeder tray, I figured that there might be something good in there. When I pulled off the side panel, I found 4 more motors! These are 24 volt brushed Mabuchi RS-385RN motors. They are used to turn camshafts that push the toner cartridges into position as they sequentially put the 4 tonor colors onto the print drum. Here is a shot of those motors.
When I pulled off the top cover of the feed tray, I noticed that there were a bunch of polished hardened 6mm steel shafts inside. These would make nice motor shafts for the 50mm brushless motors, since they currently have a built-in helical cut gear on the output shafts. Here are the steel shafts I found.
I started pulling out the shafts and the motors out of the input tray, and found even more inside. Here are the 4 brushed motors I spoke of earlier.
By the time I was done, I had a whole table full of cool parts to play with. Here is a photo of all the stuff that I eventually took from the printer.
All together I ended up with the following:
Three 50mm brushless motors
One ~35mm brushless motor
One stepper motor
Five magnetic clutches
Three 24 volt cooling fans
One 10mm steel shaft
Two 8mm steel shafts
Eight 6mm steel shafts
One 5mm steel shaft
Plus a whole box of nice screws, bushings, washers and E-clips.
I popped open the big brushless motors and found some nice stators inside. The 2 larger ones are 50mm diameter by 18mm thick, and the smaller one is 50mm diameter by 13mm thick. The motors have dual ball bearings that look to be around 6mm ID x 14mm OD x 5mm thick. Here is a photo of one of the larger stators.
And here is a shot of the stator with the tape measure, it's just a tad under 2 inches (50 mm)
So there you go! If you get a chance to pick one of these up at an auction or yard sale or company scrap pile, you know that there is a bunch of stuff good stuff inside!
|May 24, 2006, 07:36 AM|
I have at least 4 of those 50mm big ones as well as 15+ from the laser prisms. You're right, the large laser do yield alot of good stuff. I haven't found time to tinker with mine yet.
I may try just the remag first and run it up. The stock wire is pretty thick and may be fine. With the right mags and/or a rewind, they should produce quite alot of wattage.
|May 24, 2006, 12:57 PM|
Joined Nov 2003
Wow lucien talk about a jackpot.
What lam thickness are those stators, as best you can tell... also, what winding scheme. From the pictures it looks like a little deceptive. Can't tell if 7 adjacent poles are wound the same direction or maybe they soldered everything to the board and terminated 'em afterwards...?
|May 24, 2006, 01:53 PM|
The motor appears to be a standard ABCABCABCABC wind terminated in a Wye configuration. I took a couple more close-up photos and they show a lot more detail. Here is the first one.
This is a photo of the one with the 18mm thick stator. I counted the stator laminations, and there are 36 of them, so that means that they are 0.5mm thick each. A little on the thick side, but still pretty common for this size motor. You can see the wires coming down off the stator and soldering into the PC board. If you look real close, at the bottom right end of the stator, you can see the common point for the 3 winding ends. I took another photo from a different angle and circled the termination point to make it more visible. Take a look at this one.
The 7 poles that look strung together are simply the ends of the windings zig-zaging their way back to the spot of the motor where they need need to be soldered together. I suppose I could energize the coils with a small DC voltage and use my flux meter to see which poles are energized and the polarity of each to determine the exact winding scheme.
This motor is wound with wire that has a diameter of 0.024", which makes it 22 AWG. It might be good for a high voltage hi Kv application, but it is a little thin to be pumping much current through. The can says that it is a 24 volt motor, so I guess you could run it on 6-8 Li-Po cells, as long as you kept the current down. There is enough wire left over on the starts, so I could probably re-configure it as a Delta wind if I wanted to.
I looked at the 13mm thick motor as well, and it is wound with 0.020" wire, which is 24 AWG according to my wire charts. It has 26 laminations, making them 0.50 mm thick as well. I also took my digital calipers and measured across 2 opposite pole in several places, and the OD of the stator is exactly 50.25mm.
It is hard to say what the winding count on the motor is without un-winding one of the poles. It looks like there are 4 levels of wire on each pole with 12-13 wraps per layer, with the last layer only half wound, so I would have to guess that there are somewhere between 40-45 turns per pole. This would make sense, since the motor is designed for rather low speed, very high torque operation, feeding paper throught a laser printer.
The motor driver chip on this board is a Sanken SLA6024, which is a 3-phase NPN-PNP Darlington transistor array. The part has a typical gain of 5000, and has a maximum voltage rating of +/- 60 VDC, and a maximum current rating of +/- 8 Amps DC. Based on this, I would guess that the part was running on 24V DC and probably no more than 5-6 amps putting the motor in the 120-140 watt range. This seems right, since the magnet in the can is the rubber variety like you see in PC Case Fans, and is about 4mm thick.
To get any real power out of this stator, you would have to re-wind it and re-mag the can with some stronger NdFeB magnets. I would guess that you could probably get more that 1000 watts from a stator this size, but with the thick laminations, you would have to watch the stator temperature closely at first.
|May 24, 2006, 02:47 PM|
I just finished running some tests, and I have determined the winding scheme and magnet poles for the motor. I hooked up a battery with a dropping resistor to run about 500ma of current through the windings on the motor. I then took my Flux Probe and measured the magnetic field of each pole. The results were exactly what I had expected.
The stator is wound with a standard ABCABCABCABC wind. The weird thing was the magnet configuration. Usually with 12 teeth wound the way they are, you would expect 10 or 14 magnet poles, but the magnet ring inside the can had 8 poles. Looking at the winding charts, this makes sense from a manufacturing standpoint. Both 10-pole and and 14-pole designs require more complex winding schemes, namely AabBCcaABbcC. With either 8 or 16 magnet poles, the ABCABCABCABC winding scheme is used, and that is a lot easier to manufacture. The 8 magnet pole would provide a higher Kv that 10 or 14 poles would, so that could be a plus, since these big motors turn rather slow to begin with.
I measured the actual thickness of the magnet ring, and it is 3.7mm thick. This will make it a little hard to re-magnet the rotor can and maintain a good airgap. I am sure I would have to play with stacking different sizes together to get something close to fitting. Has anyone else come up with a good size magnet to use, or has anyone used the stock magnet ring with any success?
I would like to hear from anyone else that has done this.
|May 24, 2006, 05:50 PM|
Definately worth it to give George a call at engconcepts.
I'm sure he could come up with something, he has saved my butt
on numerous crazy BL motor builds.
Great find Lucien!
|Jan 24, 2007, 10:15 PM|
USA, OH, Cincinnati
Joined Sep 2006
Another facsinating, and well documented article!
ive recently extracted an almost Identical motor (50mmx14mm)
from an Brother Laser printer.
Was wondering if you had (actually) or had intended further
building of this stator?
It's most impressive after stripping so many CD and HDD sized motors,
....just wondering of its potential.
Appreciate any recommendations or further thoughts you (or anyone)
would care to share.
ps- Congrats + Best Wishes with Innov8tive!
|Jan 26, 2007, 11:39 AM|
the scene of the crash
Joined Mar 2005
how mucgh do you want for one of the big ones shipped with stator bearings and can. i would like one. pm me if you are interested in selling one to me.
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