One hour CD ROM construction pt 6

continued on from here: http://www.rcgroups.com/forums/showt...83#post2133783

Hows that, my 100th post and the first on part 6! Does anyone know why the gobrushless webpage seems to be down? I've tried to get onto it afew times today with no luck. Maybe an update happening?

Matt.

Its not down from here, I just got access as normal.

Roger

oops

Yep, just did too. Thaught I was going to have to give my credit card a bashing. Hopefully not too much longer for the custom cans so I can go nuts!

Matt.

Originally Posted by Ron van Sommeren

Ssatoru's method

Of course, credit goes to Takao Shimizu-san. All unusual come from him.

Here is another extreme CDROM motor work by Mr. Ono in Sapporo, Japan. Over 1kg thrust!

He uses the bell from Mabuchi EG-530AD-9B motor found in cassette tape player. Stator is from NEC CDR-1400C, dia is 23.9mm. Used several to make it 15 mm thick. Used 12 N35 15x6x2.8 magnets.

0.5mmx2-10T
1200 3S /GWS8040DD/9500rpm/7.5A
1200 3S2P/APC11x5.5/7000rpm/16.5A

Satoru

It is a good motor, the first measurement with the gws 8040 prop shows 78% efficiency (I have accurate measurements with this propeller), the second 58-60% (based on the rpm drop, not accurate because the battery voltage drop unknown)

Originally Posted by ssatoru

Of course, credit goes to Takao Shimizu-san. All unusual come from him.

Do you know if there is any advance in Takao's brushless controller development project, please?

Amos,

For the double ender, I would try to align both the stators on the
bearing tube and the bells (as long as they are identical mag/pole
configurations). If you have remag'ed the bells, aligning shouldn't
be a big task. (Pinpointing the N/S poles on the stock ring mags
can be fun, but it should be possible to get close enough with little
effort.) If everything is reasonably precise you should be able to
parallel the windings on a single controller with no problem. Your
actual output will depend on the precision of the alignment, but
reasonable care should get you in the high 90 percentile of the
sum of the outputs of the individual motors. If separate controllers
are used, you will not be able to attain the same max because of
'firing' variations between the two controllers (there might also be
some obscure non-linear load balance issues between the two
controllers).

John

Originally Posted by mmormota

It is a good motor

Thank you mmormota. I will let Mr. Ono know. He will be happy for the endorsement.

Shimizu-san is still working on development, having difficulty in the quality of development tool. Hope it will be solved soon.

Satoru

what about using two separate but equal motors and one controller. I have receives a wide variety of answers ranging from "death to the controller" to your situation with coupled motors. Please help!!!
Doc

Originally Posted by docnjoj

what about using two separate but equal motors and one controller.
Doc

Hi Doc,

My friend tried once and I heard it was very tricky. He used Jeti Advanced 8A? controller. Needed to try a few times to start both spin. Once they are spinning, it is ok unless you stop them. (cannot restart!) This makes flight very tricky. If he stops and starts the motors in the air, it is likely only one motor spins, creates unballance and resulted in spiral! Need to land without power.

I do not think you damage the controller unless you force it run continuously with one motor stalled.

Satoru

Hi Mr Satoru
Could the restart problem be due to lack of power (parallel vs series)?
thanks doc

Originally Posted by docnjoj

Hi Mr Satoru
Could the restart problem be due to lack of power (parallel vs series)?
thanks doc

No, it is synchronization issue. Both motors needs to spin synchonized. It is rare both motor starts completely synchonized. Brushless motors needs to be connected parallel to run, by the way.

Hope this helps.

Satoru

Many thanks Mr Satoru
Particularly for parallel vs series. I have a Phoenix 25 which should be able to handle two 5-8 amp motors!
Doc