Crane duty motors

Crane motors are often subjected to extreme weather conditions (high humidity, high salt content in the air and high wind speeds). When used in steel and smelting works, the crane motors are also exposed to particularly high temperatures as well as dust, dirt and slag.

MENZEL crane motors are typically designed for ambient temperatures of up to 40°C, optionally up to 80°C. the robust housing is optimally protected against the penetration of dust into the smelting works (protection class IP55).

For special applications (e.g. marine), we are always able to produce special designs which are, for example, protected up to 100% against humidity or particularly salty atmospheres.

The operating modes of electrical machines are described in the international version of IEC 60031-1 and EN 60034-1. The describe the load of an electric motor in terms of size, duration and chronology, including start-up, braking, no-load operation, and pauses.

Operating mode S2 describes the short-term operation of crane motors. According to DIN EN 60034-1, this means operation at a constant load, without the thermal equilibrium being reached, and with a subsequent pause in which the motor temperature decreases to the temperature of the coolant.

The labeling of operating mode S2 is typically supplemented by the indication of the operating time in “min”, for example S2 – 10 min.

Operating mode S3 was previously labeled as AB – periodic duty. According to DIN EN 60034-1, it describes an operation which consists of a series of identical cycles. Each one includes operating time with constant load, and downtime with currentless windings. In operating mode S3, the starting current does not significantly affect the excessive temperature.

The labeling of operating mode S3 is typically supplemented by the indication of the relative duty cycle (ED) of the motor, for example S3 – 40% ED.

Operating mode S4 refers to periodic intermittent operation with the influence of the start process. This means an operation which consists of a series of identical cycles, without reaching the thermal equilibrium. Each cycle consists of significant lead time, operating time with constant load, and downtime with currentless windings.

The labeling of operating mode S4 is typically supplemented by the indication of the relative duty cycle (ED), the moment of inertia of the motor, and the moment of inertia of the load machine, for example S4 – 25%; JM = 0.15 kgm²