Some of the couplings in used world wide
Two coupling standards (Biostat and Applikon) have been designed that smart they became a standard and allow some kind of interchangeability among various PCS manufactures.
Walter-Flender PowerGrip WK-PG21 combined with the ID39-B servo motor adapter as used on: Kollmorgen by Sartorius (Biostat), Kollmorgen by CerCell, and Kollmorgen by Finesse. Walter-Flender PowerGrip 43 SF combined with the ID50-B servo motor adapter for larger Biostat PCS.
Spring coupling OD14x33 with nylon grip for OD8 mm axle as used by Applikon, Broadley-James, DASGIP and others for the ID25-A size.
Magnetic coupling as used on MagMotor C21-K175
magnetic coupling for 6SM 27LL+27M
magnetic coupling as on Kollmorgen 6SM
Some brands use magnetic couplings working great for SUBs with limited power requirements like <10 watt. The black Magnetic coupling as used by NBS on the servo motor MagMotor model C21-K175. The shining magnetic coupling as used on Biostat with the Kollmorgen model 6SM servo motor.
Guardian 18PG used on MOOG servo motor by NBS for older BioFlo STR bioreactors. Red Rotex rubber element as used by Pierre Guerin STR bioreactors with Animatics servo motor.