This glossary covers 40+ terms from industrial motor terminology: efficiency classes, ATEX explosion protection, IP codes, class society approvals, mounting forms and duty cycles. Each definition is technically correct and intended for purchasing managers, superintendents and technical managers.

Efficiency and rendement classes

IE efficiency class
International Efficiency class per IEC 60034-30-1. Ranges from IE1 (standard) to IE5 (super premium efficiency). Since 1 July 2023, IE3 is mandatory in EU for 0.75-1000 kW motors in continuous duty, IE4 for 75-200 kW.
IE3, Premium Efficiency
Mandatory in EU since 2017. Efficiency at 75 kW 4-pole: minimum 95.4%.
IE4, Super Premium Efficiency
Mandatory in EU since 1 July 2023 for 75-200 kW. Efficiency at 75 kW 4-pole: minimum 96.2%.
IE5, Ultra Premium
Not mandatory but achievable via SynRM or PMSM. Typically requires VFD.
IE6, Hyper Premium
Not yet formally defined. Used by manufacturers like ABB for SynRM motors with ~40% loss reduction vs IE3.
SynRM, Synchronous Reluctance Motor
Achieves IE5/IE6 efficiency without rare-earth magnets. Operates only with VFD, not direct on grid.

ATEX and explosion protection

ATEX
European directive 2014/34/EU for equipment in explosive atmospheres. Mandatory for zone 0/1/2 (gas) and 20/21/22 (dust). Marking: II 2G Ex db IIC T4 Gb.
Ex db, Flameproof
Protection method for zone 1 and 2 gas. Enclosure prevents internal explosion from escaping. ABB M3JP, M3KP.
Ex ec, Increased Safety
For zone 2 gas. Prevents arcing and high temperatures under normal conditions. ABB M3GP. Lighter and cheaper than Ex db.
Ex tb, Dust Ignition Proof
For zone 21 and 22 dust. Dust-tight enclosure prevents ignition. IP6X mandatory. For flour, sugar, plastic and coal dust environments.

IP codes and protection

IP code
International classification per IEC 60529. First digit (0-6) = protection against solids, second (0-9) = water. For marine applications, minimum IP56.
IP55
Dust-protected + water jets. Industrial under cover.
IP56
Dust-protected + powerful water jets. Minimum marine deck equipment.
IP66
Fully dust-tight + heavy seas. Open-deck marine and offshore.
IP67
Dust-tight + temporary submersion 1 m / 30 min. Bilge pump motors.
IP68
Dust-tight + permanent submersion. Required for submersible motors like Trident.

Duty cycles and mounting forms

Duty cycle (S1-S10)
Load-time classification per IEC 60034-1. S1 = continuous, S2 = short-time, S3-S6 = intermittent, S7-S10 = special regimes.
S1, Continuous duty
Constant at rated load. Default for pumps, fans, compressors.
Mounting form
Mechanical configuration per IEC 60034-7. B3 = foot mounting, B5 = flange, B14 = small flange, B35 = combined foot+flange, V1 = vertical shaft-down.
B3
Foot mounting horizontal. Most common configuration.
B5
Flange mounting with spigot. No feet. Pump and mixer applications.
B14
Small flange without spigot. Light applications up to ~5.5 kW.
B35
Combined foot + flange. Flexible installation possible.
V1
Vertical shaft-down. For vertical pumps and fans.
Frame size (IEC mounting size)
Per IEC 60072. Frame number = shaft height in mm (frame 200 = 200 mm). Determines bolt pattern, shaft diameter, flange.
Pole count
Determines speed at 50 Hz: 2-pole = 3000 rpm, 4-pole = 1500 rpm, 6-pole = 1000 rpm, 8-pole = 750 rpm.

Class societies (marine certification)

Class Society
Independent organisation that approves marine equipment. Mandatory for essential service motors.
BV, Bureau Veritas (FR, 1828)
Often required for vessels under French flag or Mediterranean operation.
LR, Lloyd's Register (UK, 1760)
Strong in oil & gas and commercial shipping. UK flag, British offshore.
DNV, Det Norske Veritas (NO, 1864)
Market leader offshore and gas tankers. North Sea, Scandinavian flag.
ABS, American Bureau of Shipping (US, 1862)
Required for American port calls under USCG and US-flagged vessels.
RINA, Italian society
Mediterranean and Italian merchant fleet.
ClassNK, Japanese Nippon Kaiji Kyokai
Japanese flag and Asian cargo fleets.

Dredge and submersible applications

CSD, Cutter Suction Dredger
Suction dredger with rotating cutter head for hard bottom. Trident motors up to 5000 kW per cutter shaft.
TSHD, Trailing Suction Hopper Dredger
Trailing-suction hopper dredger. Picks up material while sailing via drag arm. For soft to medium-hard ground.

Procurement and service terms

Essential Service
Class category for critical equipment. Bow thruster, main engine cooling, fire pumps. Requires class survey and certificate.
AVP, Authorized Value Provider
Certified channel partner programme. Van Bodegraven Elektromotoren has been AVP for the Benelux for several years.
OEM, Original Equipment Manufacturer
The manufacturer that supplied the original motor. OEM replacement provides 100% match but typically 3-6 month lead time.
Like-for-like replacement
Replacement by motor with identical dimensions, flange, terminal box, power, voltage, pole count, mounting form. No installation modifications.
Refurbished motor
Fully disassembled, cleaned, tested, possibly rewound. 6-12 months warranty. Dormot Renew up to 1500 kW.
VFD, Variable Frequency Drive
Controls motor speed by varying supply frequency. Saves 30-50% energy on variable load. ABB ACS580/ACS880/ACQ580/ACH580.
Metaalunie terms
General delivery conditions of trade association Koninklijke Metaalunie. 2025 version filed at Rotterdam court. 30-day payment, retention of title, manufacturer warranty.