Question 1

IE3 and IE4 - what do these efficiency classes mean in practice?

Accepted Answer

IE (International Efficiency) is the classification in the IEC 60034-30-1 standard for the efficiency of induction motors: IE2 is the historical minimum level, IE3 (Premium Efficiency) reduces thermal losses by about 10-15% compared with IE2, and IE4 (Super Premium Efficiency) adds a further 10-15% saving, usually through a permanent-magnet rotor or an optimised winding. The difference shows in the energy bill, not in the purchase price - an IE4 motor costs more initially, but in continuous operation (over 4000 hours/year) it pays for itself through lower consumption. For pumps and fans running non-stop we recommend at least IE3.

Question 2

How do I choose the right power of an electric motor for an application?

Accepted Answer

The rated power must cover the maximum resisting torque of the driven machine, not just normal operation - for pumps and fans the starting torque matters, for conveyor belts the torque at maximum load. Also check the duty type (S1 for continuous operation, S2-S9 for intermittent duty), the required speed, the available supply voltage and the ambient temperature in the hall - above 40°C or at high altitude, the motor must be derated. An undersized motor overheats and repeatedly trips its thermal protection; an oversized one costs more and has lower efficiency at partial load.

Question 3

What does ATEX certification mean for an electric motor?

Accepted Answer

ATEX classifies equipment by the zone in which it can operate safely: zones 1 and 2 for flammable gases and vapours, zones 21 and 22 for combustible dust. An ATEX-certified motor carries a marking such as II 2G Ex db eb IIC T4, which indicates the equipment group, the category, the type of protection (flameproof, increased safety), the gas group and the maximum surface temperature class. Choosing the wrong category or temperature class for the real hazardous zone is a safety issue, not just a compliance one - which is why we always ask for the project's zone classification before quoting.

Question 4

What is the difference between a plain motor and a gear motor?

Accepted Answer

A plain motor delivers the rated speed of the rotor (usually 1000-3000 rpm at 50 Hz) directly on the shaft. A gear motor integrates a speed reducer (gears, worm gear or planetary) that reduces the speed and multiplies the available torque, expressed by the transmission ratio (for example 1:20). For conveyors, mixers or freight lifts, where high torque at low speed is needed, the gear motor is the standard solution - fitting a plain motor with a separate gearbox is possible, but it takes more space and requires additional coupling alignment.

Question 5

What data do I send to receive a correct quotation for a motor?

Accepted Answer

The safest is a clear photo of the nameplate of the existing motor: power (kW), speed (rpm), rated voltage and current, IE class, IP protection degree and mounting type (B3 foot-mounted, B5 or B14 flange-mounted). For a new application, we need the required torque, the desired speed, the installation environment (normal, damp, dusty or ATEX) and whether the motor will be controlled through a variable frequency drive. Without this data, any quotation remains only a rough estimate.

Question 6

How long does delivery of an industrial electric motor take?

Accepted Answer

The lead time depends on the type of motor. For standard induction models, in the usual powers and speeds, it is 24–72 h when the item is available locally or at the supplier. ATEX motors, specially configured servo motors or gear motors with a particular transmission ratio are made to order, usually 1–4 weeks; it can take longer depending on the brand and the specifications. For production lines that are stopped, we check availability before confirming the lead time.

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