Explosion proof motors, otherwise referred to as EX motors or ATEX motors are a special type of motor that are designed to be used in hazardous environments where the risk of an explosion is higher.
Whether it’s high humidity, extreme temperatures or dust in the air, an explosion proof motor has safety features in line with the ATEX directive to keep the environment safe.
At Bay Enterprises in Ireland, all of our specialist engineers are ATEX certified and can work on all types of EX rated motors. The Training is to the requirements of IEC 60079-19 Explosive Atmospheres Part 19 Equipment repair, overhaul and reclamation. An ATEX certification is required in order to work safely on explosion proof motors.
What Is a Potentially Explosive Atmosphere?
Under the ATEX (ATmosphere EXplosible) directive which covers equipment used in potentially explosive atmospheres, a potentially explosive atmosphere exists when “a mixture of air gases, vapours, mists, or dusts combine in a way that can ignite under certain operating conditions”.
With electric motors, the most common causes of explosion are the surface becoming so hot during operation that it causes ignition or a single arc from a motor malfunction causing ignition.
For this reason, equipment such as motors that are used in these atmospheres must be specially designed so that they will not cause the atmosphere to ignite, with protections against environmental hazards such as dust, fire and, moisture.
ATEX Directives (European Union)
There are two ATEX directives, one for the manufacturer and one for the user, relating to what equipment and work is allowed in an environment with an explosive atmosphere.
-ATEX 95 Equipment Directive: this concerns the standards of equipment and protective systems that are going to be used in potentially explosive atmospheres. It has become
-ATEX 137 User Directive: this directive imposes the minimum requirements for improving health & safety for workers who may be at risk from explosive atmospheres.
Types of Explosion Proof Motor
There are several types of explosion proof motor for use in different environments. The most common types of protection offered by ex motors are:
Dust ignition proof (Ex t) – When dust enters a motor, it can cause damage and potentially ignite. Dust ignition proof motors have a high ingress protection rating meaning that they can prevent any dust from entering the motor.
Flameproof (Ex d) – A spark or flame from a motor can result in an explosion in hazardous environments. Flameproof motors have flame paths built into their shaft and inner bearing covers, joints with long spigots to prevent the flames escaping and are encased with a motor housing developed to withstand internal explosions.
Increased safety (Ex ec & Ex eb) – Previously called ‘non sparking’ motors, these motors do not spark during normal operation or on start up. There are also no hot surfaces within the motor during running or starting.
The most suitable motor for your operation will be dependent on the hazards present within the environment and the job the motor is required to perform.
Ingress Protection (IP) Ratings
A key property of ex motors that makes them suitable in potentially explosive atmospheres is that they can protect against moisture and solid foreign objects.
If dust, water, or a larger foreign object enters a motor it can cause, damage, motor failure or even a spark or flame that could result in an explosion.
The degree of protection offered by ex motors is shown by the IP rating which will be found on the motor nameplate. The IP rating is made of two digits which show how well the motor is protected against both water and solid foreign objects.
Certification Markings
On an ATEX motor nameplate, you will also find the information relating to the motor’s construction and level of protection. Under the ATEX directive, the following will be present on an ex motor:
-CE marking
-ID of the body responsible for approval
-European Commission mark
-Equipment group
-Equipment category
To see the EX register of certified EX Repairers please click the link below.
https://www.theaemt.com/members-directories/full-member-directory.html?certificates=aemt-ex-registered-repairer
To find the Bay Enterprises company listing, please select the below link.
https://www.theaemt.com/full-member/bay-enterprises-munster-limited.html
Please reach out to enquiries@bayenterprises.ie for more information on any ATEX EX rated Motor enquiries.