The 350C and 350CD chopper heads come encased in a protective box and thus no additional protector is available. The 300HF high frequency accessories use the Moir fringe effect to enable light beams of larger size to be chopped. The 300HF consists of a fixed blade on a mounting plate which bolts onto the standard 300H chopping head. When the two blades are out of phase, almost the entire beam is blocked. The 360C system, a miniature OEM chopper, uses the 360H head.
Reduction gearing greatly extends the lower range of chopping frequencies.
The motor runs at its normal speed, and the reduction gearing slows the turning off the boss on which the disk is mounted. The 300-series disks are mounted on this boss. Other Parts All rotating blade choppers, including the miniature systems, use the 300S optoswitch . This is included as an item in the head and is also available separately. The 300I-A has 2 cylindrical DIN connectors, and is found on older 300C and 300CD systems.