Gregory,
I will most likely try new bearings, I have the blws motor so mine are different but I can find some. Thank you.
Update on another part of this build. I purchased both the round belt and flat belt pulley from sdp-si.
Both are concentric and work well.
The round belt one was ment for a 1/8" belt. I purchased that with it and found that it added vibration and did not hold speed as well so I used it with a 1/16" or 2mm belt and it performed great. I found though that the round belt pulley did not fit that great on my motor shaft. It was tight and would get stuck trying to take it on and off even with the set screw removed.
For that reason I also purchased their flat belt pulley and a flat belt. This pulley fit on well and did not have that same issue. It was more finicky in terms of setup and getting it at the right height for the belt to stay on. Overall though it lowered noise, not inaudible but less than before(still going to try bearings), and it runs I think more speed stable although I have no tried a test record or the script that is in another thread here, only based on my tachometer readings.
Both are worthwhile depending on your setup and for their relative inexpensive are worth simply trying.
Here are links to the ones I used. I ended up using the .512 flat belt and I am satisfied.
Product | Designatronics Store | Stock Drive Products/Sterling Instrument
Product | Designatronics Store | Stock Drive Products/Sterling Instrument
Product | Designatronics Store | Stock Drive Products/Sterling Instrument
Both are concentric and work well.
The round belt one was ment for a 1/8" belt. I purchased that with it and found that it added vibration and did not hold speed as well so I used it with a 1/16" or 2mm belt and it performed great. I found though that the round belt pulley did not fit that great on my motor shaft. It was tight and would get stuck trying to take it on and off even with the set screw removed.
For that reason I also purchased their flat belt pulley and a flat belt. This pulley fit on well and did not have that same issue. It was more finicky in terms of setup and getting it at the right height for the belt to stay on. Overall though it lowered noise, not inaudible but less than before(still going to try bearings), and it runs I think more speed stable although I have no tried a test record or the script that is in another thread here, only based on my tachometer readings.
Both are worthwhile depending on your setup and for their relative inexpensive are worth simply trying.
Here are links to the ones I used. I ended up using the .512 flat belt and I am satisfied.
Product | Designatronics Store | Stock Drive Products/Sterling Instrument
Product | Designatronics Store | Stock Drive Products/Sterling Instrument
Product | Designatronics Store | Stock Drive Products/Sterling Instrument
I am driving a subplatter and not an exterior platter so my circumference is not relevant. The belt is .25" tall and .02" thick. sdp-si doesnt have large enough belts for external platter drive but this place does and it is where I purchased mine. Flat Turntable Belts By Size – Turntable Tuneup
If someone has a cheaper source for flat belts I would appreciate that. I can live with the $10-15 but cheaper would always be preferable.
Hi everyone.. looks like I MAY currently have an option for shipping over an AA motor to the UK
Just wondering does anyone in the US happen to have a spare board for sale for the MA-3D and possibly also the SG4 with latest chip (although I know I can get these in the UK from Ralph)
I would just need it posted within the US.
Please PM me if you can help.
kind regards
realjuliano
Just wondering does anyone in the US happen to have a spare board for sale for the MA-3D and possibly also the SG4 with latest chip (although I know I can get these in the UK from Ralph)
I would just need it posted within the US.
Please PM me if you can help.
kind regards
realjuliano
I an considering to try a flat belt, as I see a difference between one and two belts. I think a flat maybe better still. Only If I try will find out.
I have the BLWR motor running for a bit now, and speed seems to be quite good, although there is almost no part of the turntable currently in a "final" state.
That said, I have noticed some unwanted behaviour with the motor - when running at 45rpm, it seems to produce a rattling/scratching noise. Well, mostly rattling.
This comes from the motor only, and is present when I remove the belt and the pulley.
Once back to 33.3rpm, all seems good and the noise vanishes.
The SG4/MA-3D combo is setup meticulously, and the offset is minimal (well within expected limits).
Any thoughts to what I might be doing wrong? I would like to avoid replacing the motor bearings if I can - but will do if it cures the noise.
I would like to eliminate issues with the SG4/MA-3D first.
That said, I have noticed some unwanted behaviour with the motor - when running at 45rpm, it seems to produce a rattling/scratching noise. Well, mostly rattling.
This comes from the motor only, and is present when I remove the belt and the pulley.
Once back to 33.3rpm, all seems good and the noise vanishes.
The SG4/MA-3D combo is setup meticulously, and the offset is minimal (well within expected limits).
Any thoughts to what I might be doing wrong? I would like to avoid replacing the motor bearings if I can - but will do if it cures the noise.
I would like to eliminate issues with the SG4/MA-3D first.
45 RPM should have higher running voltage than 33. Can you confirm that the DC supply is adequate to prevent clipping of the signal. It would be quite helpful if you have access to a scope. Alternatively, try reducing the running voltage and see if that makes any difference. It could just be a faulty motor, but I've bought over a dozen motors from AA of different sizes and mounting types, without a problem in any of them.
I've acquired an adjustable PSU (adjustable in fixed increments) to power the MA-3D and SG4. It can be set to anything between 12V and 24V.
Currently set at 15V as per the original BOM. At 15V it deliveres 2.2A.
What would be the parameters for an adequate PSU?
Reduce voltage via the SG4?
I will try to make arrangements to have it reviewed on a scope.
Reduced voltage to ~4VPP (for 45rpm) via SG4 and the noise is somewhat reduced - but still noticeable.
I will try to have it looked at through a scope.
Is the MA-3D using 2.2A when the motor is running or is the PSU capable of 2.2A.
If the current consumption is 2.2A, that's 33W, that is way too high. At 12VPP (4.25VRMS) to the motor, the total current consumption (MA-3D and SG4) should be less than 750mA.
Something else to try:
If the motor is vibrating, there may be a slight imbalance in the rotor. If the motor is not mounted to anything, the vibrations can build until they are audible and can be felt by holding the motor in your hand. In most cases, mounting the motor to a case with some mass will dissipate the vibration before it can build. You can test this by holding the motor tightly to a bench top and see if the vibrations subside.
If the motor is vibrating, there may be a slight imbalance in the rotor. If the motor is not mounted to anything, the vibrations can build until they are audible and can be felt by holding the motor in your hand. In most cases, mounting the motor to a case with some mass will dissipate the vibration before it can build. You can test this by holding the motor tightly to a bench top and see if the vibrations subside.
Motor is mounted to an aluminium pod, with a Delrin cap, and a steel base. Weighs approximately ~5kg, and in 33.3 mode, is absolutely silent.
Pyramid, I managed to get a bronze pulley with 3/8'' (9.525mm) of diameter. Your calculations to determine the right freq to the motor are:
Motor RPM/Platter RPM= (Platter Dia + 1/2 T)/(Pulley Dia +1/2 T) Where T=Thickness of belt.
33.3 = (11.8 + 1/2 0.07) / (0.375 + 1/2 0.07)
If I'm not mistaken the result is 961,23RPM. So the freq is:
Motor RPM=60*Freq/pole pairs
Freq = 961,23RPM*2/60
Freq = 32.04HZ
Do I need to make any changes on the voltage of the motor amp?
Thank you!
Motor RPM/Platter RPM= (Platter Dia + 1/2 T)/(Pulley Dia +1/2 T) Where T=Thickness of belt.
33.3 = (11.8 + 1/2 0.07) / (0.375 + 1/2 0.07)
If I'm not mistaken the result is 961,23RPM. So the freq is:
Motor RPM=60*Freq/pole pairs
Freq = 961,23RPM*2/60
Freq = 32.04HZ
Do I need to make any changes on the voltage of the motor amp?
Thank you!
I'm getting 962.195 motor RPM for 33.3333 platter RPM which is a frequency of 32.073Hz for the BLWS series motor. The voltage should be ~14.32VPP or 5.06VRMS. A 15VDC supply will still work for this.
For 45 RPM, I get 1299 motor RPM, 43.3Hz and 17.4VPP or 6.15VRMS. You will need a higher voltage power source for 45 RPM (18-24VDC).
Both of those motor voltages are with the SG4 at maximum (128) for start up. The running voltage should be reduced by 8-10% for both 33 and 45.
Thank you!!
So from the MA-3D Assembly Instructions pdf file, the changes are: 1) preset the right freq 32.07hz/43.3hz (33/45rpm); 2) adjust the SG4 Reduced for 5.06VRMS to 33rpm and 6.15VRMS for 45rpm (BLWS)?
So from the MA-3D Assembly Instructions pdf file, the changes are: 1) preset the right freq 32.07hz/43.3hz (33/45rpm); 2) adjust the SG4 Reduced for 5.06VRMS to 33rpm and 6.15VRMS for 45rpm (BLWS)?
Both of those motor voltages are with the SG4 at maximum (128) for start up. The running voltage should be reduced by 8-10% for both 33 and 45.
The frequencies are approximate, but a good starting point. Adjust them using a strobe or tach.
The frequencies are approximate, but a good starting point. Adjust them using a strobe or tach.
Using a Arduino Tach I managed to get 33.33/33.34 with ~33.10hz (33rpm), not very stable tho.
Here's a picture using the motor with a TT Project 1xperience.
Dropbox - IMG_4901.JPG
Here's a picture using the motor with a TT Project 1xperience.
Dropbox - IMG_4901.JPG