Pre-StartPurge
and MotorPurge
Expo's Pre-StartPurge and MotorPurge systems provide explosive
protection for HV motors in flammable atmospheres.
An explosion risk can exist within Ex n and Ex e electric machines
on 'start-up' from the existence of flammable gas that has entered
the machine casing due to:
- Ingress through inward leakage caused by the
circulating/cooling fan
- Ingress during cooling following shutdown
- Ingress due to thermal cycling
Expo’s Pre-Start and MotorPurge systems have been developed
to allow clients to comply with IEC/EN 60079-15 [Ex n] and IEC/EN
60079-7 [Ex e] standards where there is a requirement to purge
(ventilate) the machine enclosure to remove any hazardous gas prior
to the machine being energized or re-energized.
Ex n and Ex e electric machines should not be energized if there
is a potential explosive atmosphere within the machine enclosure. The
gas may have entered the machine prior the starting or during the
normal operation of the machine and prior to the machine being
stopped. In both instances the Pre-Start system should be operated
before the machine is energized.
IEC/ATEX equipment designed to this concept is suitable for use in
Zone 1 and Zone 2 hazardous locations.
For USA equipment designed to this concept is suitable for use in a
Class I, Division 2 hazardous location.
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