430.7 Marking on Motors and Multimotor Equipment
- Manufacturer's name.
- Rated volts and full-load current. For a multispeed motor, full-load current for each speed, except shaded-pole and permanent-split capacitor motors where amperes are required only for maximum speed.
- Rated frequency and number of phases if an ac motor.
- Rated full-load speed.
- Rated temperature rise or the insulation system class and rated ambient temperature.
- Time rating. The time rating shall be 5, 15, 30, or 60 minutes, or continuous.
- Rated horsepower if 1/8 hp or more. For a multispeed motor 1/8 hp or more, rated horsepower for each speed, except shaded-pole and permanent-split capacitor motors 1/8 hp or more where rated horsepower is required only for maximum speed. Motors of arc welders are not required to be marked with the horsepower rating.
- Code letter or locked-rotor amperes if an alternating-current motor rated 1/2 hp or more. On polyphase wound-rotor motors, the code letter shall be omitted.
Informational Note: See 430.7(B).
- Design letter for design B, C, or D motors.
Informational Note: Motor design letter definitions are found in ANSI/NEMA MG 1—1993, Motors and Generators, Part 1, Definitions, and in IEEE 100—1996, Standard Dictionary of Electrical and Electronic Terms.
- Secondary volts and full-load current if a wound-rotor induction motor.
- Field current and voltage for dc excited synchronous motors.
- Winding — straight shunt, stabilized shunt, compound, or series, if a dc motor. Fractional horsepower dc motors 175 mm (7 in.) or less in diameter shall not be required to be marked.
- A motor provided with a thermal protector complying with 430.32(A)(2) or (B)(2) shall be marked "thermally protected." Thermally protected motors rated 100 watts or less and complying with 430.32(B)(2) shall be permitted to use the abbreviated marking "T.P."
- A motor complying with 430.32(B)(4) shall be marked "impedance protected." Impedance-protected motors rated 100 watts or less and complying with 430.32(B)(4) shall be permitted to use the abbreviated marking "Z.P."
- Motors equipped with electrically powered condensation prevention heaters shall be marked with the rated heater voltage, number of phases, and the rated power in watts.
- Motors that are electronically protected from overloads in accordance with 430.32(A)(2) and (B)(2) shall be marked "electronically protected" or "E.P."
The code letter indicating motor input with locked rotor shall be in an individual block on the nameplate, properly designated.
Table 430.7(B) Locked-Rotor Indicating Code Letters
|Code Letter||Kilovolt-Amperes per Horsepower with Locked Rotor|
|V||22.4 and up|
Exception: Constant horsepower multispeed motors shall be marked with the code letter giving the highest locked-rotor kilovolt-ampere (KVA) per horsepower (hp).