N
NAMEPLATE
The plate on the outside of the motor describing the motor, HP, voltage, RPM’s, efficiency, design, enclosure, etc.
NAVY SERVICE “A”
Motors designed to meet requirements of MIL M-17059 or MlL M-17060 for high shock and service and are essential to the combat effectiveness of a ship. These motors are usually made of nodular iron.
N.E.C. TEMPERATURE CODE (‘T’ CODE)
An index for describing maximum allowable “skin” (surface) temperature of a motor under any normal or abnormal operating conditions. The “T” codes are applicable to U.L. Listed explosion-proof motors. The skin temperature shall not exceed the minimum ignition temperature of the substances to be found in a hazardous location. The “T” code designations apply to motors and other types of electrical equipment subject to hazardous location classification.
SKIN TEMPERATURE IDENTIFICATION NUMBERS
| Maximum Surface | Degrees F | T-Codes ID Numbers | U/L Requirement for Class & Group |
|---|---|---|---|
| 450 | 842 | T1 | |
| 300 | 572 | T2 | |
| 280 | 536 | T2A | Class I Group D w/Cautionary Label |
| 260 | 500 | T2B | |
| 230 | 446 | T2C | |
| 215 | 419 | T2D | Class I Group D |
| 200 | 392 | T3 | Class ll Group E & F |
| 180 | 356 | T3A | Class I Group C w/Cautionary Label |
| 165 | 329 | T3B | Class ll Group G |
| 160 | 320 | T3C | Class I Group C |
| 135 | 275 | T4 | |
| 120 | 248 | T4A | |
| 100 | 212 | T5 | |
| 85 | 185 | T6 |
NEMA
The National Electrical Manufacturers Association (http://www.nema.org) is a non-profit organization organized and supported by manufacturers of electric equipment and supplies. NEMA has set standards on:
- H.P. ratings
- speeds
- frame sizes and dimensions
- standard voltages and frequencies with allowable variations
- service factors
- torques
- starting current & KVA
- enclosures
NODULAR IRON (DUCTILE IRON)
Special cast iron with a crystalline formation which makes it capable of handling high shock.