188.8.131.52 Mounting. Motor-generator sets are mounted on rigid independent
foundations fabricated from structural steel. They are secured with SAE Grade 5
fasteners or ASTM A325 bolts with matching nuts and hardened steel washers.
Motors. DC motors can be categorized as either industrial or mill duty
type; all AC motors are industrial type.
184.108.40.206 Mill Motors. AISE Standard No. 1 defines the design criteria,
capabilities, and dimensions of DC mill motors.
220.127.116.11 Industrial Motors. NEMA Standards Publication No. MG-1 provides guidance
for the selection and application of motors. It addresses ratings, terminal
markings, dimensions, and testing of AC and DC motors. It also prescribes minimum
requirements for information, which must appear on motor nameplates.
18.104.22.168 Nameplate Data. Both the National Electrical Code (NEC) and NEMA
Standards Publication No. MG-1 require that a motor's nameplate include:
Motor's rated voltage and current (current for each speed if a two
speed squirrel cage AC motor);
Frequency and number of phases (for an AC motor);
Rated full load speed;
Rated temperature rise or the insulation class and rated ambient
Locked-rotor amperes or locked-rotor kVA indicating code letter and
design letter (for a squirrel cage AC motor);
Secondary voltage and full load current (for a wound-rotor AC
Winding type (for a DC motor).
There are additional requirements in NEMA Standards Publication No. MG-1
(MG 1-10.66.3 for DC motors/MG 1-10.40.1 for AC motors), beyond those of NEC
Section 430-7, for information to be provided on a motor nameplate.
To meet NEMA requirements, the following information must be provided for
DC motors in addition to that required by the Code:
Manufacturer's type and frame designation;
Maximum safe speed for series-wound motors and certain compound-
Maximum ambient temperature;