Motors used within a hazardous location require a higher level of protection against the risk of harmful occurrences. CMG motors are available in the three most common high protection configurations, Ex e, Ex nA (formerly Ex n) and Ex tD (formerly DIP), supplied with protection ratings IP55, IP65 or IP66. CMG Hazardous area motors are available in motor frame sizes 71 to 400. Combinations of protection such as Ex e and Ex tD or Ex nA and Ex tD are also available.
Motor protection types
Ex e motor protection designates Increased safety as outlined in IEC, EN or AS/NZS 60079-7.
The increased safety (Ex e) type of protection describes electrical equipment that does not produce arcs or sparks in normal service in which additional measures are applied so as to give increased security against the possibility of excessive temperatures and of the occurrence of arcs and sparks.
Increased safety (Ex e) motors are suitable for Class I, Zone 1, Group II (A,B&C) hazardous areas, and CMG provides for a temperature class of T3 (200°C) in a 40°C ambient (see next page for explanations of classes, zones and groups).
Ex nA (formerly Ex n)
Ex nA motor protection designates Non-sparking as outlined in IEC, EN or AS/NZS 60079-15. Non-sparking (Ex nA) type of protection describes electrical equipment that, in normal operation, is not capable of igniting a surrounding explosive atmosphere, and a fault capable of causing ignition is not likely to occur.
Non-sparking (Ex nA) motors are suitable for Class I, Zone 2, Group II (A,B&C) hazardous areas, and CMG provides for a temperature class of T3 (200°C) in a 50°C ambient.
Ex tD (formerly DIP)
Ex tD motor protection designates dust-excluding ignition proofing as outlined in IEC or AS/NZS61241 series of standards.
Dust-excluding ignition proofing (Ex tD) type of protection describes electrical equipment which is enclosed so that it excludes dust, and which will not permit arcs, sparks or heat otherwise generated or liberated inside the enclosure to cause ignition of exterior accumulations or atmospheric suspensions of a specific dust on or in the vicinity of the enclosure.
Dust-excluding ignition proofed (Ex tD) motors are suitable for Zone 21 and 22 dust laden hazardous areas, and CMG provides for a temperature class of T4 (135°C) in a 50°C ambient.