Brushless motor controller for a tape recorder capstan

[avetius]

Hi everybody,

Trying to replace an old brushed motor with a brusheless one in an old tape recorder. Naturally it requires a controller so I wonder if this could be built on microcontroller board and how complicated would it be. Here is what I have to deal with:

- 24v input power
- about 10W-13W brushless motor with hall sensor
- 2 distinct rotation speeds
- 2 rotation directions
- RPM pitch control with an encoder (±20%)

Being a tape recorder, the rpm accuracy and consistency is of absolute importance, that's why the most important question is "how accuratly a microcontroller can manage the rotation speed?" I met many cases where the rotation adjustments happen too slow resulting in rythmically floating of the sound.

I am a hobbyist, some skills in electronics but almost no knowledge in microcontrollers. So any hint or advise would be great to start with: like what kind of board would fit, are there suitable libraries o codes I could use? etc...

Thanks in advance

 

[KlausST]

Hi,

there are ready to buy ICs doing this for you.

Instead of a (feedacked) regulation loop you may also do forced RPM control (not feedbacked). Then the RPM accuracy can be as good as your XTAL clock.

But please first do a search for an IC, go the the manufacturers and read datasheets and application notes.
This is how I´d do it.

Klaus