DC motor psu

[kephaudio]

Hi dears,

I have just got a DC motor from Maxon UK. I now start with thinking about the Psu.

What are the points to get here? I want the voltage set by a potentiometer, I don't trust in fixed voltage things, also because I want to play 33,1/3 and 45 on the same deck without boring with double pulley.

So what I have to care about, do you have some schematics to start with? How much caps? Is the LM317 good for this job?

Let me know guys, bye for now

Kepha
Record of the day: King Crimson, "Discipline"

[krishu]

Hi,

speed depends on (mechanical) load, so ordinary LM317 might not be the best choice. I was told that a "fast" LT1086 is better but that depends very much on the motor's specs. the motor must be chosen so that it operates in a speed and load configuration which is optimal. Otherwise the speed will vary across platter radius as well as on the amplutude of the music signal (because the needle in the groove will slow down the platter). This is no theory, I tried hard for several years. If you have a light platter and the rightly chosen motor, the LT1086 configuration might work, but then there is another problem: the voltage deluivered by the voltage regulator is somewhat dependimng on temperature. All that leads to the point that thee must be some feedback, either from the motor itsewlf or - better - from the platter. See the Teres power supply. No easy job.

If you want to succeed in an easier way use a PLL DC motor (e.g. Scheu or modified Papst Variodrive) or synchronous motors and maybe sinus generator for the latter one.

Kind Regards
Christian.

[winggo]

I've found a manufacturer of a good regulated power supply that will give you a constant 12 or 24 volt DC supply to the motor. US Digital in Vancouver. WA. Phone 1(800)736-0194, web site is www.usdigital.com.

I had purchased an Oriental Motor Co. DC motor with controller (24 volt) and when I tried to get it set up with a standard 24 volt power supply it would go into voltage overload fault. It needed exactly 24 volts, no more, no less. The US Digital PS-24 PSU worked great and for only $24.00.

I think that when you start off with a stable power supply you are better off. It seems to me that maintaining a constant speed with what ever motor you are using will be easier with a regulated power supply.

My only problem with my motor set up is that the Orient Motor (Vestra) DC motor is way too noisy. Well, back to the drawing board. What ever I end up using for a motor and speed controller I plan on using a regulated DC power supply.

George

[sreten]

Hi,

as far as I'm aware a basic DC motors speed is dependent on
applied voltage and the loading of the motor is a secondary
effect, you need to look at the slope of the speed torque curve
to predict the effects of the (minimal) turntable loading.

Starting torque is another issue. IMO the "speed" of the regulator
is completely irrelevant, and an LM317 should be fine, though I'm
not familiar with the fine details, e.g. temperature compensation.

/sreten.

[Algar_emi]

Check my thread:

Never Connected HR Supply circuit

I built an upgrade power supply for my turntable dc motor.

It may help you...

Bye.

[spacejay]

Very interesting series.

Has anyone else made one of these and if so what were the results.

[spacejay]

Sorry posted this in the wrong place (I know that I am an idiot)