Refers to a motor that, under normal operating conditions, will not ignite surrounding explosive mixtures and generally will not experience ignition failures. Compared to increased safety motors, except for the insulation dielectric strength test voltage, winding temperature rise, te (the time taken for the AC winding to reach the rated operating final temperature after starting current is applied until it rises to the limit temperature at the highest ambient temperature), and starting current ratio, which do not have special regulations like increased safety motors, other aspects are the same as the design requirements for increased safety motors.

Spark-free motors comply with GB3836.1-83 and GB3836.8-87 "Explosion-proof electrical equipment for explosive environments, spark-free electrical equipment 'n'" regulations. The design focuses on the sealing measures of the motor, with the main housing protection level being IP54 or IP55, and the junction box being IP55. For motors with a rated voltage above 660V, the connection components of space heaters or other auxiliary devices should be placed in a separate junction box.

Domestic YW series spark-free motor products have been developed and produced (with a frame center height of 80~315mm). The explosion-proof mark is nIIT3, suitable for factory areas containing combustible gases or vapors with temperature groups T1—T3 forming explosive mixtures in zone 2. The rated frequency is 50Hz, and the rated voltage is 220, 380, 660, or 380/660V. The motor uses F insulation but is assessed according to B class for the temperature rise limit of the stator winding, providing a large temperature rise margin and high safety reliability, with a power range of 0.55~200kW.