Washing Machines: Centrifuges & Vibration

You put your clothes in. The machine spins. Suddenly, it starts walking across the laundry room floor with a deafening THUMP-THUMP-THUMP. You have an Unbalanced Load. Physics is punishing you.

The Centrifuge

A washing machine spins at 1200 RPM to sling water out of the clothes (Centrifugal Force).

• Force = $$Mass \times Radius \times AngularVelocity^2$$.
• If you have a heavy wet towel on the Left side, and nothing on the Right side, the center of mass is off-center.
• As it spins, that off-center mass yanks the entire drum sideways 20 times a second.

The Passive Suspension

Laundry machines hang the drum on massive springs and use concrete blocks as counterweights to absorb this. If the imbalance is too high (>10 lbs), the springs bottom out, and the machine walks.

Robot Flywheels

In robotics, we spin plastic wheels at 5000 RPM to shoot balls. If that wheel is unbalanced (even by 1 gram):

1. Vibration: The entire robot shakes.
2. Blur: The camera vision gets blurry.
3. Loose Screws: The vibration rattles bolts loose.
4. Efficiency: The motor works harder to fight the shake.

We balance our flywheels just like a car tire mechanic balances a tire: We drill holes in the heavy side or add tape to the light side until it spins silently. Silence is efficiency.