Julian Oh, congratulations on completing your EX protection qualification! Before you explain what this means now you can implement this qualification: What is actually meant by "EX protection for motors"?
"EX protection for motors" basically means the protection of motors that are used in a potentially explosive environment. For example: a coal mill drive that supplies a coal-fired power plant with finely ground coal in order to be able to burn it efficiently afterwards: Ground coal also settles as conductive dust on the slip rings and brushes of a motor. This causes sparks and can lead to an explosion.
When we at MENZEL talk about "explosion protection for motors", we usually mean large motors that are needed for hazardous areas where harmful gases may be present in an industrial plant. Our family-owned company, which has been operating globally for over 90 years, manufactures these motors for customers in various industries. In the case of explosion-proof motors, we are currently focusing on motors in petro-chemical, gas and dust environments.
Motors can therefore be the cause of a dust or gas mixture igniting, causing an explosion in the area they are situated. How is this prevented?
A risk assessment is carried out in advance. There are various explosion protection categories or defined hazard levels that are assigned to the motor by international standards. The labelling system in explosion protection is really complex. It specifies, for example, the equipment group, equipment category, equipment protection, temperature class, etc. Our customer, or the operator of the industrial plant, specifies which protection class the desired electric motor should have. MENZEL, as the manufacturer of the motor confirms in turn that the newly manufactured motor fulfils all conditions for the designated protection class.
And how is an explosion prevented? Well, the topic is really very complex; I'll expand a little further without going into too much depth. Basically, the following three factors must come together for an explosion to occur:
- A flammable substance
- Sources of ignition
To prevent a possible explosion, there is primary, secondary and tertiary explosion protection.
Primary protection aims to replace the flammable substances or atmospheric oxygen or to reduce their quantities so that the formation of an explosive mixture can be excluded. Such as a well ventilated operating environment or keeping any layer of dust down by cleaning, are basic examples, of primary protection.
If the primary protection is not sufficient or cannot be fulfilled, secondary protection measures take effect. For this purpose, possible ignition sources are identified and evaluated, then subdivided into so-called "zones". The frequency and duration of the occurrence of a possible explosion are also determined and very specific protective measures for the construction of the motor are then derived from this.
If the primary and secondary protective measures are not sufficient, additional measures must be taken. Examples of tertiary explosion protection are: the motor is built to be pressure-resistant, fault rated protection terminal boxes are installed, and in some cases the motor is purged of possible gasses before starting, and much more.
Therefore, it is your role to check compliance with the necessary protective measures, right?
Yes, exactly, as an "explosion protection expert" I know the standards that have to be complied with and check whether they are being met. Ideally, I can then certify that the motor has been manufactured in compliance with the required standards and protection class. Or I explain exactly what still has to be fulfilled by the production department in order to be able to confirm the required explosion protection.
So, how did it come about that you are now an "Explosion Protection Qualified Person"?
Shall I be completely honest? I was asked if I could imagine it, went on holiday and when I came back I had the registration for the training on my desk (laughs).
And the more detailed answer: Since we at MENZEL offer explosion-proof motors, it must of course be ensured that the employees responsible for them are always up to date with the latest knowledge regarding technology and standards. The manufacturer must comply with these comprehensible regulations by continuously training responsible employees or having them certified with regard to explosion protection. That is why I have now undergone this qualification.
Before that, a valued external colleague did this for us, and I am now following in his footsteps. I have been responsible for the so-called Technical Documentation at MENZEL for several years, which is at the interface between sales and production. That's why I had been working closely with our Explosion Protection Officer for a long time: If he found fault with something, I looked for - and found - ways to "iron it out" together with my colleagues. So I have been familiar with the subject for many years.
What is the most exciting and the most challenging thing about this new task for you?
The most exciting and at the same time the most challenging thing is that every motor - and therefore every explosion protection test procedure - is different, because at MENZEL we manufacture customised motors for our customers. In concrete terms, this means that we do not develop a specific motor model, which we have certified once by the certifying authority TÜV and then produce in repetative series. Rather, each motor is an individual item, complete with its own necessary unique additional attachments or temperature conditions that must be observed – along with individual explosion protection requirements in order to function as a reliable and low-risk drive for the customer.
As you progress, what is the next stage in this qualification process?
First of all, my goal is to keep up to date with explosion protection regulations. In addition, I will continue to work on the topic of occupational safety and seek to be certified as an "officially qualified person" at the state level. In my private life, I'm planning to get my boating licence in 2023.
We wish you every success for it!
Interview: Lisa Ernsting; Date: 22.12.2022