u/Illustrious_Hope5465

Hi everyone! I’m a student doing an experiment in involving a Pololu 25D gearmotor (5A stall), a 30V/10A bench PSU, and spinning carbon fiber rods with N52 magnets. I’m setting up a dedicated lab in a small back house room and need an table to function as my electronics workbench. I am looking at using IKEA furniture now, so I am looking for suggestions.

1. I need a surface that won't vibrate like crazy when the motor hits high RPM and mess with the tachometer readings.
2. I will be ordering from the UK as my dad tends to prefer getting things from there.

Hi, I’m setting up a small physics experiment where I attach a neodymium bar/cylindrical magnet to a DC motor so it rotates as a magnetic dipole.

A coil is placed nearby to measure induced voltage as the magnet rotates.

My question is about the mounting:

• The motor I am looking at has a steel 4 mm diameter shaft
• I would likely glue the magnet directly onto the shaft
• I’m worried the steel shaft (and possibly gearbox parts) might distort the magnetic field of the magnet

What I’m trying to avoid is unintentionally changing the magnetic field geometry in a way that affects measurements. I also don't know whether to use epoxy or a mechnical method.

So I’d like to know:

1. Does a steel motor shaft noticeably distort the field of a small neodymium magnet mounted on it?
2. At a few cm distance (where the coil would be), is this effect negligible?
3. Would it be better to use a non-metallic coupling (plastic hub / spacer) instead of direct mounting?
4. Or is direct mounting generally fine for this kind of setup?

I’m mainly trying to preserve a clean “rotating dipole” field as much as possible.