They're used as replacements for parts that have cracked

NFPA 30 Standards

which are fashioned out of 11-gauge stainless steel

Spring Disc

Dayton 1/4 HP Belt Drive Motor, Split-Phase, 1140 Nameplate RPM, 115 Voltage, Frame 56CZ - 6XH44BG Capacity-Two Jumbo Rolls They're used as replacements forNEMA service factors up to 1. 40 provide a reserve margin for applications where intermittent overloading or fluctuating (high low) voltage conditions may occur. Provides direct replacement in many Jenn Air and similar commercial kitchen exhaust ventilators. For use in exhaust ventilators in commercial cooking areas and other moderate starting torque equipment that can be directly connected to a NEMA 56CZ face mounted motor.