# Setting a Motor so that it spins at a certain RPM [closed]

I'm making a record player for a school project and I'm having trouble with the motor that will spin the platter. I'm using a belt drive system, so I have two circles connected by a pulley system. Using the velocity ratio and pulley formula (knowing that the platter had to have a diameter of 100mm and spin at 33.3 RPM, and the motor spindle would be 5.55mm diameter) I worked out that the motor would have to spin at exactly 600 RPM.

I have no knowledge in electronics so any help would be massively appreciated. Could you please suggest a way I could buy a motor online and a way to control the motor so that I could get it to spin at exactly 600RPM? I've been looking at motors like these and adjustable motor speed controllers like these but I am unsure what motors would have the right voltage and amps, and whether the variable controllers would be compatible with them?

If anyone could suggest a combination of motor, and an adjustable motor speed controller and possibly even a way to put them together I would be so grateful. This is for a school project to finish.

## closed as too broad by Daniel Grillo, Voltage Spike, uint128_t, Dave Tweed♦Dec 3 '16 at 16:43

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• how do your power your whole project? I certainly hope you're not plugging in mains. – Christian Dec 1 '16 at 11:40
• You need to define "exactly". "Exactly 600RPM" is not meaningful, does it mean 600RPM ± 10RPM or 600RPM ± 0.0001RPM? – uint128_t Dec 2 '16 at 18:35
• Note that LP records spin at $33\frac{1}{3}$ RPM, not 33.3. – Dave Tweed Dec 3 '16 at 16:42