3 Phase Class D amp for DIY BLDC motor Drive

Problem posting photos - please help

Hello everyone.

I promised to post photos of Micro Seiki RX-5000 clone with SG4/PAPST drive. 3 phase BLDC is to be tested with the same turntable.

For some reason I am unable to upload photos. All my attempts failed with the same message stating that 'security token is missing'.

I've contacted forum support and tried what they suggested to fix the problem but it did not work.

Does anybody else have problem uploading/posting photos? Is there a solution for this issue?


Thanks.
 

rif

Member
Joined 2003
Paid Member
I'm looking for a 0.25 inch. Did he give you a price quote for 10?

He's asking $85/piece in a 10 piece batch.

So do we go with an unknown machinist, but human, and pay a lot more. Or emachineshop.com and pay significantly less ($23/piece for 10 pieces).

If we go emachineshop.com, I wouldn't mind fronting the money if someone else handles placing the order and subsequent distribution to individuals. That's what I've been doing with twysted for the sg4 chips and it seems to work.

BTW, I emailed Anaheim automation, the motor is in stock even if the web says it isn't.
 
He's asking $85/piece in a 10 piece batch.

So do we go with an unknown machinist, but human, and pay a lot more. Or emachineshop.com and pay significantly less ($23/piece for 10 pieces).

If we go emachineshop.com, I wouldn't mind fronting the money if someone else handles placing the order and subsequent distribution to individuals. That's what I've been doing with twysted for the sg4 chips and it seems to work.

BTW, I emailed Anaheim automation, the motor is in stock even if the web says it isn't.

If it helps, I could probably have a local machine shop, one that I am working with on my turntable, turn the pulleys for approximately $20/each at 10 pieces. This is white POM (Delrin) and I can front the material for it at no cost (for no more than 10 pieces). Two caveats:

1. Would need to ship the full batch to someone in the USA for further distribution since I can do a flat pack from here (Macedonia) at a small cost.

2. Imperial fitting tolerances might be an issue (mostly metric sized tooling here).

But it is an option if you want to go with a human, albeit unknown to most, machinist.

P.S. Bronze is also an option. Machining would not be much more (if any) but shipping would be more expensive, and there would be extra material cost.
 
Last edited:

rif

Member
Joined 2003
Paid Member
He's asking $85/piece in a 10 piece batch.

So do we go with an unknown machinist, but human, and pay a lot more. Or emachineshop.com and pay significantly less ($23/piece for 10 pieces).

If we go emachineshop.com, I wouldn't mind fronting the money if someone else handles placing the order and subsequent distribution to individuals. That's what I've been doing with twysted for the sg4 chips and it seems to work.

BTW, I emailed Anaheim automation, the motor is in stock even if the web says it isn't.

The machinist made an error - it woukd be $59/piece
 

rif

Member
Joined 2003
Paid Member
If it helps, I could probably have a local machine shop, one that I am working with on my turntable, turn the pulleys for approximately $20/each at 10 pieces. This is white POM (Delrin) and I can front the material for it at no cost (for no more than 10 pieces). Two caveats:

1. Would need to ship the full batch to someone in the USA for further distribution since I can do a flat pack from here (Macedonia) at a small cost.

2. Imperial fitting tolerances might be an issue (mostly metric sized tooling here).

But it is an option if you want to go with a human, albeit unknown to most, machinist.

P.S. Bronze is also an option. Machining would not be much more (if any) but shipping would be more expensive, and there would be extra material cost.

Do you have a good, active relationship with them? In person or just email? I'm assuming you trust them since you've entrusted them to an entire turntable. I'd value that more than my Craigslist machinist.
 
Do you have a good, active relationship with them? In person or just email? I'm assuming you trust them since you've entrusted them to an entire turntable. I'd value that more than my Craigslist machinist.

:)

I live in a small town. For every part that gets machined, we discuss engineering drawings in person. It is mostly a one-man shop.

I could have him machine one and send it off to the US for a sample fit?
 
On the AA motors, it is mentioned they are ball bearing designs.
In what way are they mechanically as quiet as the typical sintered oil style bearings?
One would have to seriously isolate the motor to appreciate the speed benefit gained.
Can,t see how a ball bearing would not transmit some vibration thru its housing

The seperate motor pod type of isolation is the only way to use these correct?

Regards
David
 
On the AA motors, it is mentioned they are ball bearing designs.
In what way are they mechanically as quiet as the typical sintered oil style bearings?
One would have to seriously isolate the motor to appreciate the speed benefit gained.
Can,t see how a ball bearing would not transmit some vibration thru its housing

The seperate motor pod type of isolation is the only way to use these correct?

Regards
David

You'll have to try one of the motors to see just how quiet they are. They use precision sealed bearings that do not need to be lubricated, on both ends of the shaft. There is no end play of the shaft at all and they are totally silent. The bearings can handle much larger radial loads and won't wear like the bronze bearings do, which leads to vibration.

I looked for several years to find a BLDC motor with friction bearings, but I could not find one. I finally decided to buy one of these motors in order to complete the controller and worry about the bearings later. When I received the motor, even turning the shaft by hand, I could not believe how smooth they were. They produce much less noise and vibration than any of the Hurst AC synch motors that I have and would easily be an improvement on a plinth mounted motor ie the VPI Classic series table.
 
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I took apart both BLWS and BLWR motors to check build quality and construction details.

One thing that I did not expect to see is dynamically balanced rotor in both motors. This certainly lowers rotor vibration and level of noise generated.

Next, ball bearings are press fit onto shafts and preloaded with wave washers. There is absolutely no axial movement/play that I could detect mo matter how hard I was pulling/pushing the shaft.

There is barely detectable cogging when shaft is turned by hand in the motor with 4mm shaft and no cogging at all in the motor with 1/4" shaft.

I am trully impressed with the mechanical construction and build quality of AA motors. I cartainly did not expect it in this price category.

In couple of days I will have Maxon DC motor and controller in my hands. Retail price is slightly over $500. Rest assured I will take the motor appart to see what makes it 5x more expensive than one from AA.

My circuit boards are out for delivery today. I will build two amps, one for each type of AA motor, and test over the weekend.

Report will follow in few days...
 
Pyramid, just wondering if you have a finished controller you could post pics of.
Also, what platter diameter are you using to determine pulley diameter?

Thanks, Greg

These photos are in the assembly instructions as well.

The pulley diameter is for use with an 11.5" platter. If you have a 12" platter, it will still work, but the 33 RPM freq then becomes 20.87Hz (41.74Hz for BLWR series) and 28.17Hz for 45 RPM (56.35 hz for BLWR series).
 

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