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Apr 26, 2005, 08:06 PM
Just Keeping UP
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Stock CDRom Rebuild


I've built and recommended these stock CDRom motors from GoBrushless and have been asked a number of times for help from others. Thus, I'm posting this thread on how to go about rebuilding these motors.

It's possible this has already been done, but here goes anyway.

Below is a photo of a couple of GoBrushless stock CDRom motors and a finished rebuilt one.


Step 1: Grab the plastic disk and magnet bell in one hand and the metal plate in the other and pull the motor apart. It should now look like the second photo below.

Nick
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Apr 26, 2005, 08:23 PM
Just Keeping UP
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Step 2: Removing the plastic disk: Look inside the magnet bell and you will see three black plastic dots. These are the 'heads' of three plastic posts that have been 'heat staked' to the magnet bell. See first photo below:

Take a 3/32" (or there about) drill bit and BY HAND 'drill' the plastic dot off. I use a pin vise to hold the drill bit and use it like I'm trying to drill a hole at the dot. When done, it should look like the third photo below.

Now take a small flat screwdriver and insert gently between the plastic disk and the front of the magnet bell, as shown in the fourth photo, and gently pry the plastic disk off. See photo five below.

Use some Acetone on a paper towel to clean the glue residue off. Feel free to toss the plastic disk.

Nick
Apr 26, 2005, 08:36 PM
Just Keeping UP
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Step 3: Removing the stock magnet ring. Some people use these motors with the stock magnet ring. If you want to do this, skip this step. There is supposed to be a thread in this forum about this but I don't know where it is. Perhaps someone will post a link to it.

The magnet ring is glued in place. The ring may be pried out in pieces. You can soak the bell in Acetone for a while to desolve the glue. Or, you can apply heat to soften the glue and remove the ring. I find this the easiest and quickest way to remove the stock magnet ring. (But then, I own a micro-torch) I apply heat with a micro-butane torch as shown below.

Hold the motor shaft in a large pair of pliers and gently apply the torch flame around the bell until the glue begins to smoke. Set the torch down and gently pry the magnet out. It it doesn't come out very easily, use more heat.

Now let the bell cool. Now remove EVERY TRACE of glue from the inside of the bell where the new magnets will be glued in. If there is any glue left here, the magnets will end up too close to the stator and may rub.

If you like, you can chuck the bell in a drill motor and polish to a nice shine with fine sandpaper.

Nick
Last edited by nfhill; Apr 26, 2005 at 08:51 PM.
Apr 26, 2005, 09:14 PM
Just Keeping UP
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Step 4: Removing the metal plate and PCB from the bearing holder and stator.

This is the easiest part. Place the stator inside a 15/16", or 24 mm, socket and sgueeze gently with a vise or C-clamp as shown in the photo. With just a little preasure, the bearing holder and stator will pop loose.

Carefully cut, or desolder, the three wires from the PCB. Handle these wires VERY carefully. They break easily. If they break, this project will immediately become more complex because you will need to rewind the stator.

Of course, you may wish to strip and rewind the stator to customize the winds and motor specs to your use. If you do this, count the turns and post the count so the rest of us will know how many turns of wire are 'stock' for this motor.

When done, you will have the magnet bell and stator/bearing holder ready to begin reassembly.

Nick
Apr 26, 2005, 09:29 PM
Just Keeping UP
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Step 5: Preparing the magnets.

Place 12 each 5mm x 5mm x 1mm magnets is a single stack as shown below.

One by one, mark the SAME face of each magnet with an indelible marker. Let each mark dry before handling so you don't rub the ink off. Then place it on a knife blade or metal ruler.

If you place the magnets in a row on a metal ruler or knife blade, they will NOT STICK TOGETHER when the orientation is the same. This is the way you want them to be.

Nick
Apr 26, 2005, 10:05 PM
Just Keeping UP
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Step 6: Gluing the magnets in the bell.

This is the hard part. Fortunately, if you mess up, the glue can be loosened with Acetone and the magnets removed so you can start over.

This is a 22.7mm stator motor and the magnets need to have a gap of 0.04", or 1.1mm, between each one. You can do this by eye, by making a spacer, or by buying a special magnet spacer tool from GoBrushless or Strong Motors. I've done it each way and I now have a spacer tool! This makes this step easy! The proper tooling always makes the job easier.

The Goal: Place the magnets neatly around the inside wall of the bell, evenly spaced, with the dots alternating visable and not visiable (dot to the inside, dot to the outside). The top of the magnets should be even with the top of the bell wall: this makes the height easy to hold consistant and easy to keep the magnets straight. I use the tip of a screwdriver to pull the magnets even with the top of the bell wall. Without a spacer, the magnets WILL attract each other and the proper spacing will be hard to hold. However, even without a spacer, the magnets will stay properly separated due to friction with the can. The photo below without the spacer was made with NO glue holding the magnets. Of course, I put the spacer back in before gluing because I always manage to touch and move the magnets otherwise. (My hands shake.)

Each magnet should be glued in place with a SMALL drop of thin CA. To much CA and you'll glue the spacer in place and get glue on the inside face of the magnet where you don't want it. Once all of the magnets are in place, the spacer is removed and a little more glue may be added.

A word about quality: While you want the magnets to be perfectly spaced and aligned, they don't have to be perfect for the motor to run. Close is good enough: you be the judge of how close is good enough for you. The important thing is to have the magnet orientation ALTERNATING.

There's really nothing more I can say about this step. Just do the best you can. (easy for me to say, I know. )

Nick
Apr 26, 2005, 10:28 PM
Just Keeping UP
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Step 7: Inspect.

After the magnets are all glued in place, inspect them to be sure that the magnets alternate dot visable and dot not visable. Also check to see if there is glue on the inside face of the magnets. If there is, carefully clean it off with Acetone on a paper towel.


Step 8: Wires and connectors.

I use servo wire to make a connection pigtail. Carefully solder a wire to each of the magnet wire ends. Insulate with a piece of heat shrink tubing and secure the wires so that you CAN NOT FLEX the magnet wire. If you can flex the magnet wire when handling and using the motor, it's only a matter of a SHORT time before the wire will break and the motor will not run properly. If this happens, you will most likely have to strip the stator and rewind it. Therefore, I use epoxy to stabilize the wire connections and prevent any movement of the magnet wire.

Add connectors of your choice. The finished motor shown uses 0.1" spaced header and socket strips cut to length. These can be hard to obtain if you don't have a good electronics supply store available, but they work well at these low current levels and are light weight.


Step 9: Motor mount.

There are a number of ways to make a mount. A tube mount is common. You can use a short piece of 11/32" tubing, or even a 9mm shell casing (no live primer please!). Or, you can cut a custom shaped piece of plywood or plastice sheet and glue to the back of the bearing holder. It's up to you.


Step 10: Final Assembly

Oil the shaft and snap the motor together. You are ready to go!

If you ever break the nylon washer that holds the motor together, don't worry about it. The motor will hold together without it.

Go fly and have fun! I use these motors on 3S Li-Poly and a GWS EP6050 prop on my OV-10 at about 1.75 amps. I'm sure other combinations will work well. This motor is a 'star' or 'Y' wind. Keep the motor current under 4 amps and have fun.

Nick
Apr 26, 2005, 10:30 PM
Just Keeping UP
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Performance


I haven't explored the full application range for these motors. Feel free to post your own experiences!

Nick
Apr 26, 2005, 11:32 PM
"Experienced-Crasher"
Demon-Leather's Avatar

Wow!....


When I get my motors (probably tomorrow, or the next day) I'm gonna have LOTS of dumb questions to post here!... What I know about electricity.. Wrong wire...Fire.. touch here,.. ZAP.. that smarts!...Be careful NOT to let the smoke out of motor...Anyone have an extra can of smoke?... I think I may need it... Bob
Apr 26, 2005, 11:47 PM
Just "PLANE" crazy
Spy king's Avatar
Are these the motors you are talking about??
http://www.gobrushless.com/ccp51/cgi...tr=HOME:motors
-Ashwin
Apr 27, 2005, 12:10 AM
Registered User
bass3587's Avatar
Quote:
Originally Posted by Spy king
Are these the motors you are talking about??
http://www.gobrushless.com/ccp51/cgi...tr=HOME:motors
-Ashwin
I just checked out that link and this is what it had to say
"Also, check out the EZone and read about some folks who have flown using just this stock motor with no modifications at all!"
Can you actually run this type of motor with no modifications? If so what size plane and battery (lipo)?
Apr 27, 2005, 01:47 AM
Just Keeping UP
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Spy King,

Yes, those are the motors I'm describing.

I always upgrade the magnets, so I've never really looked for a thread about using them with the stock magnet ring. If you find this thread, post a link here.

Nick
Apr 27, 2005, 03:09 AM
Just "PLANE" crazy
Spy king's Avatar
what magnets do you use??
-Sry new to thins and want to get in but a little aprihensive of the price...
Apr 27, 2005, 03:13 AM
Just Keeping UP
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Quote:
Originally Posted by Spy king
what magnets do you use??
-Sry new to thins and want to get in but a little aprihensive of the price...
I used the 5mm x 5mm x 1mm. I bought a package of 50 from GoBrushless. That's enough for four motors.

Nick
Apr 27, 2005, 03:14 AM
Just Keeping UP
Thread OP
By the way, both Balsa Products and Cool Running have BL ESC's for $30 now. The Cool Running is receiving very good comments here in Power Systems.

Nick


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