UL 1004-3:2018 PDF Download

The UL 1004-3:2018 standard is an additional standard that complements and modifies the requirements of the UL 1004-1:2012 standard for Rotating Electrical Machines - General Requirements. This standard is specifically applicable to motors that rely on a thermal motor protector to prevent overheating under specific operating conditions. These motors are designated as "thermally protected motors."

The standard applies to motors that are protected by either electromechanical thermal motor protectors or solid-state thermal motor protectors. It also covers impedance protected motors in cases where the manufacturer includes a supplementary thermal motor protector.

The UL 1004-3 standard is designed to evaluate the specific combination of motor and protector. If there are any changes in either the motor, protector, or the motor/protector combination, the combination must be reevaluated according to this standard.

Additionally, the standard applies to motors equipped with coordinated protection, where one method ensures locked rotor protection, and another method provides running heating protection, as required by section 7.11 of the standard.