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Who is interested in a groupbuy of Mark Kelly's DC controller PCB and related parts

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#41
Mark Kelly said:


Both of the Maxon motors I mentioned will suit. The 226764 will give better performance at 300 rpm but will require a 35mm diameter pulley for 33 1/3 RPM. The 110191 would allow you to use a smaller pulley or run both 33 and 45 rpm.
Click to expand...


OK.

Sign me up for PCB with deluxe parts, and a pulley.


Alternativly point me to a pulley source. I am not able to find anything, maybe I should get it made at some shop..

hk
 
#42
I'm going to throw a fly in the ointment here because my conversations with a Maxon engineer verified that the self lubricating bronze bushings are ineffective at such a low RPM of 300. He said his best guess would be 600 RPM minimum.
I also spoke with a sintered bronze comany about the same thing and was told that they work best with high rpm applications and need heat to draw the oil. This is what I was told.

superhkm said:



OK.

Sign me up for PCB with deluxe parts, and a pulley.


Alternativly point me to a pulley source. I am not able to find anything, maybe I should get it made at some shop..

hk
Click to expand...
 
#44
Vinyl-Addict said:
I'm going to throw a fly in the ointment here because my conversations with a Maxon engineer verified that the self lubricating bronze bushings are ineffective at such a low RPM of 300. He said his best guess would be 600 RPM minimum.
I also spoke with a sintered bronze comany about the same thing and was told that they work best with high rpm applications and need heat to draw the oil. This is what I was told.

Click to expand...
That's interesting but it differs from the classic Morgan / Cameron analysis of lubricant flow in sintered bearings as explained here:

Tribology ABC on Sintered Bearings

I haven't found an online source for the original paper by Morgan and Cameron but my understanding is that sintered bearings with pressure load are very effective at slow speeds. Certainly the sintered thrust bearing in my TT moves lubricant into and out of the pores at very slow relative speeds.
 
#45
Mark Kelly said:


Both of the Maxon motors I mentioned will suit. The 226764 will give better performance at 300 rpm but will require a 35mm diameter pulley for 33 1/3 RPM. The 110191 would allow you to use a smaller pulley or run both 33 and 45 rpm.
Click to expand...

Forgive my ignorence; but have I got it right ?

A 20mm pulley will require ca530rpm for 33 1/3 and 715rpm for 45 and this will be fine running a Maxon 110191 on 12VDC.
 
#48
Re: Maxon 110189

superhkm said:


Forgive my ignorence; but have I got it right ?

A 20mm pulley will require ca530rpm for 33 1/3 and 715rpm for 45 and this will be fine running a Maxon 110191 on 12VDC.
Click to expand...

Close enough and the motor controller's adjustability will take care of the rest.

To be exact you need to add the product of the belt's thickness and the material's Poisson's ratio to both radii before calculating the drive ratio. In the case of rubber the Poisson's ratio is 0.5 so the easy rule is to add one belt thickness to both diameters

superhkm said:



Please let me know if I´m stepping on anyones toes, but I'm offered Maxon 110191, $96 for one, $90 for five or more.

How does these prices compare ?
Click to expand...

They are the best prices I've seen. Care to act as motor provider to the Europeans in the group buy? Depending on postage cost, maybe the US citizens too.

we416b said:
Mark,

Would this controller work with an 110189 (1st generation diy Teres)?
This motor has less than half the resistance of the 110191.

Fred
Click to expand...

Yes.

The 110189 was included in the table that somehow didn't make it into the article, but it's on my website:

Web page on DC drives

The last row in the table is roughly the performance expected using the current controller at 300rpm. As you can see the 110189 isn't quite as good as the 110191. At 600 RPM the performance of each is about 4 times as good, but belt creep gets worse.
 
#49
I made mine out of scrap stainless pipe and the machine work costs about 25 bucks for the lid to be attached. I could see if i can get some made like mine (see completing my turntable post most recent). The cap does screw on so you would just have to counter turn it to not over twist the wires
fortytwo
 
#51
Re: Re: Maxon 110189

Mark Kelly said:




They are the best prices I've seen. Care to act as motor provider to the Europeans in the group buy? Depending on postage cost, maybe the US citizens too.
Click to expand...



Only too happy to contribute! I'll get the shipping cost east coast and west coast USA (and the european) in a day or two.
 
#53
IZHAKKATZ said:
in my motor (110182) the pulley is 5 mm Dia.
That means about 2000 RPM for 33.3
Would the voltage still be too low for the controller?
Click to expand...


To be honest, I do not know how it would perform.

Three things worry me - the very low run voltage, the very high speed / voltage characteristic and the very low winding resistance. Each of these will reduce the performance of the motor drive combination, all of them together probably mean that it will not perform satisfactorily.

Even if it did, you would need to make changes to accomodate the much higher start currents this motor will pull.
 
#56
dc motor and controller

Hi Bas

please put me down for dc motor, deluxe controller and pulley. Could you advise on exact platter diameter for this pulley and controller as i am currently in the process of designing a new turntable. Also do you know anyone who can supply a very good quality inverted bearing. I may need about 5 sets in total.

sorry if this is slightly off thread but has anyone machined a platter from Acetal (better machanical properties than acrylic).
 
#58
Re: dc motor and controller

kevinchampion said:
Hi Bas
Could you advise on exact platter diameter for this pulley and controller as i am currently in the process of designing a new turntable.
Click to expand...

There is no real anwer to this as we have not standardised a pulley as yet. Vinyl Addict may care to advise on this but we will probably end up with a pulley of 15 - 20 mm diameter. With a pulley of say 15 mm diameter the controller can be adjusted to give 33 1/3 rpm for any platter diameter from 50mm to 700mm.

Speed variation due to belt creep increases with the inverse of the driven diameter of the platter so if you are starting from scratch go with edge drive.
 
#60
DC Controller, motor & parts.

Please please put me down for dc motor, deluxe controller and pulley.

I'm interested in using it with a Fairchild platter/bearing that I have rebuilt. It is a 30cm dia platter and I would like to use a tape drive pully if possible.

Please advise me of costs and approximate timing of delivery.

Cheers

Bryce
 
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