Found good CDROM brushless donor

[brogers]

I feel like I hit the jackpot. I found a CDROM motor that has a 3mm shaft, ball bearings, e-clip on the shaft with thrust washers, etc. I've been contemplating buying one, but this looks like too good of a donor to pass up. The motor came out of a Hitachi CDR-7930.

Notice the brass bushing on the bell housing is hollowed out. It also has a step so that it is always resting on the inner sleeve of the ball bearing.

[3d4me]

That's good information. It would be highly beneficial to start a thread identifying all the drives that would contribute to good quality cd motors and what those components are. hats off to you brogers. ty.

[brogers]

I added a picture.

[stirlingnut]

hey,could we get the diameter and depth of the bell,and stator diameter?
thanks

[brogers]

Bell Housing
OD: 23.7 mm
ID: 22.7 mm
total heigth: 8.0 mm
magnet width: ~6 mm

Stator
OD: 20.3 mm
ID: 8.2 mm
thickness: 5.8 mm

[WreckRman2]

That's a very popular motor for the CDROM conversions. Many guys already use that motor.

[stevem1928]

I made a brushless conversion of that exact motor. It works great with 5 x 5 x 1 magnets. If I remember right; it is 8 or 9 turn of 26 g. It draws 9 amps on 2 lipo cells w/ 4.75 x 4.75 apc prop.

[stevem1928]

By the way, be careful getting the existing magnet ring off. I nearly ruined the can trying to get it off. I had read to soak it in acetone overnight. That did not help me any. I also had trouble with this stator shorting out. The insulation seems thin. Wind carefully. I have no troubles with shorts on Gobrushless stators.

[brogers]

Steve,

I have a couple of questions. Did you leave the brass piece inside the stator or did you replace it? Right now I'm researching different ways of securing the stator using the existing brass insert that houses the ball bearings.

At my local electronics store they didn't give me much of a choice on the gauge size of the magnet wire. I ended up buying 24 gauge. I was thinking about putting the max number of turns that will fit.

[stevem1928]

I left everything just as it is. I just changed the magnets, and re-wound the stator. I left mine on the PC board. I don't know how you are going to mount it. My motor came from a CD ROM. I see yours came from a CDR. Maybe yours was not atached to the board. I will send a picture of the mount.

You may want to try a Bic pen. They work OK for the bearings and 22.7 mm stators. I think the 20 mm stators have a smaller ID. You may try a brass shell casing from a 30.06. I have used both. I will upload some pictures to help explain.

[brogers]

I see... Mine was mounted to a PC board. For some strange reason I thought it would be better to take it off. I think I could attach another plate to it and recrimp the brass to fasten it down.

[stevem1928]

Here is how I have mounted the same motor. I just trimmed the PC board, and drilled a couple of holes in it, then screwed it to a 3/8" sq dowl on the back of the plane.

[brogers]

Awesome! Thanks for the pics. :)

[stevem1928]

Here are a couple of other ways I have mounted the motors. One method uses the existing GoBrushless bearing assembly. I epoxied a plastic tube (I found an old pen with just the right ID) to the brass bearing assembly.

I have also soldered a brass shell casing to the bearing assembly. A 30.06 works perfect. Make sure to solder before youhave any heat sensative parts installed.

I have also used a Bic pen. The ID of the pen is just a hair too large. I was able to glue the bearing in place, and also use a spacer inside between the bearings. This seems to work well. The OD, is just a hair too large for the 22.7 stator. I just sanded it lightly. No bearing assembly is needed for this mount. The triple stator motor (Bic pen) in the picture in not finished. It uses a speed 400 can. The first magnets I tried, were a little too big. I tried 6 x 6 x 1.5. I think 6 x 4 x 1.5 should work. This motor requires 2 sets of 12 magnets. I have not seen anyone use a speed 400 can. It may not be possible.

[stevem1928]

Let us know how the magnet ring comes out.

[lensrc]

Heat the bell with a heat gun while holding the front of the shaft in a pair of plyers. When it gets hot enough, tap the back end of the shaft on a hard surface. The mag will fall out.

Len

[Ron van Sommeren]

An overnight/day soak in acetone will loosen the ring too.

Groeten ;) Ron

[Sonic1]

Brogers, I thought I had hit the jackpot too when I found them. Here's mine. I've since changed the collar for a C clip because it was in the way of the IPS mounting stick.

http://www.rcgroups.com/forums/showpost.php?p=2751384&postcount=67

Here it is mounted in my Pico Stick F...

http://www.rcgroups.com/forums/showpost.php?p=2755743&postcount=87

Jeff.

[Sonic1]

You can see how to take it apart here....

http://www.rcgroups.com/forums/showthread.php?t=235885&page=5&pp=50

Starting at post #216.

[Sonic1]

Here's some pics of one mounted on a Razor Saver Man mount...

[Sonic1]

Art Newland's CDR7930 EPS drive....

http://www.rcgroups.com/forums/showpost.php?p=2422903&postcount=38

http://www.rcgroups.com/forums/showpost.php?p=2394448&postcount=422

[brogers]

Thanks Sonic1 for the pictures! That is a very clean setup you're using. I was thinking about using a thin metal plate as a mount and soldering it to the brass that is pressed into the stator.

[Opie818]

Does anyone know of a quick way to get the shaft and bell true??

[Sonic1]

Does anyone know of a quick way to get the shaft and bell true??

On a CDR7930?

[two-hill]

So, where do you get a CDR 7930?

[Sonic1]

I got mine on eBay.

Jeff.

[Sonic1]

There's also a Lite-On drive out there with the same motor. I don't have a clue what model drive it's from. Probably the same vintage as the CDR-7930.

[Littlescreamers]

That motor is well known on this site and has threads for it. I have built countless motors from the 7930 and the best way to remove a ring magnet is to heat it up with a heat gun and remove it with a hobby knife,
17 turns of 26g wire star will turn a 7035 at around 4 amps. 12 turns of 26 delta will do w 4x4 at over 20,000 and I think 7-8 amps
Its a great motor.
Scott

[Sonic1]

I've had good luck with soaking it in thinner overnight and removing it with a hobby knife. I like the heat gun idea because you don't have to wait 8 hours! I'll give it a try. Scott, what rpm does that motor turn the 7035 at?

Jeff.

[Littlescreamers]

11,400
~s

[Littlescreamers]

Here is one from june 6th.
Scott

[two-hill]

Scott,
Where do you get your 7930 motors? I got 14 drives from a friendly computer repair guy. There were only two duplicates and no 7930s. Of the ones I've taken apart so far most don't look very suitable. Several have the can bearing integral with the disc drive plate.

Is a 7035 a 7x3.5 inch prop?

Phil