[AlanD]

Briefly (in responce to a request in another thread) - according to my understanding:

Basically a Harmonic Damper (a sort of rotational shock-absorber) is just an overhung (balanced) compliant-damped-flywheel which is coupled (attached) to the motor shaft with a collet or shaft-clamp through a central boss.

Think of a damper as a phenumatic-wheel with lead replacing the air.

The 'cogging' effects inherent in stepper motors leads them to become 'excited' at certain rotational frequency - this is commonly referreed to as mid-band-resonance and this is what a damper minimises by smoothing out the steps - it does this by adding a critical mass to dampen the 'cogging' - it may have disadvantages regarding acceleration/decelleration of the motor.

This one (below) appears to be a plastic moulded housing into which 'mass' has been added to give the inertia/loading.

Mass: 281gms
OD: 2.5"
Width: 0.75" (excluding the boss)
Inertia: xx?
Other features: it has a 'flag' for an interruptor/counter
Application: Fitted to a 100ozin NEMA 23 motor (as shown)