Clear screen

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Senior Member
Mar 17, 2008
Vessel Name
Isle of Skye
Vessel Make
Bruckmann trawler
I have a rotating clear screen which is giving up the ghost. If I help start it with a spin it will go for about 30 minutes before stopping, but at nothing like its original speed.
Only data I can find is on a plate with
Centerless Ind Co Ltd Tokyo
CM 300 -H
*I would really like to find an exploded view before I tear it apart (it's probably brushes) so I can either avoid having a 30cm, hole in the windshield, or at least have the plywood ready to fill the hole.
Anyone got any knowledge of this animal?
Will try to add some pics. to see if that stimulates any responses.


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Well, I'll jump in where angels fear to tread - If it were my boat and I didn't know anything about the unit's innards (and I don't), I'd start be taking those two screws out of the back and gingerly loosening the motor. That might reveal the next step, and if not it can probably be reassembled pretty easily.

OTOH, it would be better if someone who has taken one of these apart would respond.

- Peter
This looks like a knock off opf the Kent Clearview screen.

Perhaps some googeling?
Jon,I am with Peter Mc,
12 volt motors should have an armature, commutator and bearings/ bushings on each end, much like a starter. I have had success in the past with similar items by cleaning the commutator with emery cloth, checking for excessive brush wear and downward spring tension, and lightly oiling the bushing area to assure free rotation. Gu sure to mark matching areas of the housing before disassembly. If you need any parts a starter shop may be able provide.


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Ok I give up! what is it? What is a "clear screen".
Spins real fast to throw water / ice, etc. off. Kinda like a fancy windshield wiper.
And when it works it's fantastic. Sure missed it today heading south ino all the slop in St Joseph Sound.
Many thanks for the tip. SO far I'm only finding 110V/220V big ship stuff but I'll keep looking.
sounds like the way to go but I think once I start I'll end up with my 30 cm. hole as to get at the front bearing where the brushes look to live I'll have to pull the screen.Guess it's back to the duct tape and clingwrap.
"SO far I'm only finding 110V/220V big ship stuff but I'll keep looking."

The big boy's stuff has heaters in the disc to help clear the ice!

Not usually a cruising option for small boats.

Could have used it one year as we sailed from NYC to FLL at the end of Jan. Not a bad trip as the bays were ice free , and the hatch could be slid closed (seat below) so only ones head was exposed , and that was washed in warm air from below.

Went with the angels and pulled the back cover off exposing brushes. Pulled the brushes against their springs a couple of times, reassembled it and its working. Seems to be a little more noise than I remember but that might be just a little roughness on the brushes. The screen rotates very easy without power.
Would contact cleaner and q-tips help on the commutator??
Many thanks to all.
Jon,Emery cloth would help on the commutator
- I do it often. You are removing material from the surface to get back to clean brass. Sometimes I use a paint stirring stick with about 1' of 120 or so grit folded in 1/2 to access the commutator between the brush holders on industrial DC motors after replacing the brushes. I have someone operate the motor to make it spin while I insert the wooden paint stick and move it up and down as needed. In your case- if you can remove the brush holders and end of the motor- just wrap 2-3" around the commutator and twist it back and forth till shiny.
Will be in a marina later in the week so will source some emery cloth.
I've always been told 'Do Not Use Emery Cloth On Electrical" equipment. The grit is conductive. Maybe ok at 12v systems but I never tried it so from experience can't say.
I've cleaned lots of motors but never used emery.

There are lots of other grits on the market that are not conductive and readily available
*Running offshore a few miles from Naples with a chop putting spray onto the front windshield, and the Clearscreen doing the job. I used q-tips and contact cleaner to scrub at the comm. I got emery cloth butdidn't want to risk pulling off the brush holder to get at more of the comm. It will not roate with the back bearing cover removed.
Making towards Little Shark River and was planning initially to go around Cape Romano, but think I'' go in at Capri Pass and try the inland route.
Never use emery cloth to polish a commutator. It is conductive and will lead to shorted bars and grounds. Use fine sandpaper or a commutator stone. Wrap a strip of fine sandpaper around the comm with grit up and lower the brushes onto it after you have polished the comm, turn it a few times with the brushes rubbing on the paper and they will be smooth and match the comm radius. This should give you a few more years of use.
Sorry guys- I need more info on emery cloth being conductive. I did a google search and found a couple of "I heard's". I am interested to find out the reason it is conductive. I heard years ago if you placed a charged battery on the ground it would discharge. I found out later that it was due to the case construction materials used at the end of WWII. Of course this no longer applies. Any links??
Magnetite is magnetic and wreaks havoc with electric motors. Non-conductive abrasives abound. For the clear screen you can fortunately clean it easily as Rickb suggests.
Joe has been my starter giuy for most of 30 years. I asked him if he ever uses emery cloth to dress commutators. "Sure" he replied. Is it a special type? I inquired... "180 grit". Conclusive answer from a man that makes a living doing it.


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"or a commutator stone"

Rick has it right , a couple of bucks at NAPA for the right tool , which works on starters and any DC or universal (with brushes) AC motor you come across.

A broken hacksaw blade rubbed on each insulation seperation will lower it enough to usually get rid of the noise and make the brushes last lots longer.

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