Menzel Elektromotoren GmbH

Menzel Elektromotoren GmbH, Berlin/Germany, has fitted a stock motor for operation at an altitude of 4,200 m AMSL and shipped it to a gold mine in the Andes. This was an urgent order due to the failure of the existing mill motor. The new motor had to be modified so it could smoothly replace the old one (Figure 1). Menzel adapted the performance characteristics and cooling type to the high altitude, changing the cooling to IC 06 with external fans. The motor features a weatherproof design (IP24W / NEMA WPII). Further works included the changeover to double-delta, 4,160 V, 60 Hz, shortening the NDE shaft, re-milling the drive shaft and building base plates to adapt the foot holes and shaft height to the existing connections on site. The squirrel cage motor also had to be equipped for ramp-up on a frequency converter. The motor features 2,980 kW rated output, 894 min^-1 rated speed and a rated torque of 31,833 Nm. Menzel won the contract due to its fast delivery capability. The internationally active manufacturer also supplies the mining industry with custom configurations of fan and conveyor motors etc. The current project came in through Menzel’s Peruvian sales partner, who also travelled to Berlin with the user for final testing and acceptance and who supervised the commissioning.

Further information:
Menzel Elektromotoren GmbH
www.menzel-motors.com

Menzel Elektromotoren GmbH, Berlin/Germany, has configured two modular slip ring motors from its extensive stock for a ball mill in a gold mine in Kazakhstan and shipped them at short notice (Figure 1). The robust motor pair provides the necessary high starting torques for the heavy-duty application and ensures reliable operation under impact loads and voltage fluctuations. The MEBSSL motor series allows for swift individual modifications and the implementation of different features, such as various cooling and protection classes or mounting options. The series is characterized by high efficiencies, minimal operating costs, great robustness and a long service life. The two identical mill motors in size 800 are designed in the increased protection class IP55 and in cooling class IC 611 with an air-to-air heat exchanger. The nominal power is 4,750 kW, the nominal voltage is 10,000 V, the nominal torque is 45,682 Nm, with permissible maximum torques of 290 %. Menzel has manufactured and fitted new shaft ends, added new foot holes, shortened and moved the rotor terminal boxes and added additional auxiliary terminal boxes for the slip ring chamber. The motors reached the customer within a very short time, thus preventing extended, costly mill downtime. Menzel accompanied and supported the installation and commissioning. The German family-run company supplies the mining industry with suitable motors for a wide range of applications.

Further information:
Menzel Elektromotoren GmbH
www.menzel-motors.com

Menzel Elektromotoren has been certified for the production of large squirrel-cage motors in ignition protection type Ex p pressurization for operation in zone 1 hazardous areas where an explosive gas/air mixture is likely to occur in normal operation. The test specimen, a compressor motor for the petroleum industry, underwent a gas displacement test (test of the air purge system), leak test and pressure test. The German technical inspection service TÜV Nord comprehensively tested and certified the construction method. To win the approval, the manufacturer had to prove its ability to control the purging air flow for all its relevant motor series in such a way that no gas pockets remain inside the motor casing. Menzel can apply this manufacturing procedure to stock motors in a wide output range and is thus able to flexibly and quickly provide competitively priced Ex p motors featuring the product categories 2G and 3G. Pressurized motor construction is typically suitable for squirrel-cage motors from 400 mm shaft height. It is available for all voltage ranges and with air-to-air or air-to-water heat exchangers (cooling types IC 611, IC 616 or IC 81W).

An air-purge system allows potentially flammable gases to be removed from the motor frame before the motor is started and to maintain a constant positive pressure during operation to prevent the ingress of explosive gases. The terminal boxes feature the ignition protection type Ex eb increased safety.

Plant operators often face the challenge that they cannot find suitable replacements for obsolete motors. The choice of explosion-proof drive systems in particular is limited. Up until now, the only alternative was to buy a standard motor with the required explosion-protection rating and adapt the installation site and/or driven machine, sometimes at considerable time and expense. Menzel’s certification for the construction and manufacture of protected motors now gives customers more freedom of choice and flexibility. The German manufacturer specializing in large electric motors always configures motors for the individual application and installation conditions. Likewise, the air purge system for pressurized motors is individually calculated and implemented, ensuring that the finished systems meet the highest safety standards.

For a petrochemical company, Menzel has recently manufactured an Ex p compressor motor based on its MEBKSL series, which matches the original motor in all mechanical and electrical interfaces. The compressor motor for an oil refinery is labeled II 3G Ex pzc ec ic IIC T3 Gc for zone 2. It has a rated voltage of 6000 V and a rated output of 1635 kW. Before shipping, the motor was rigorously tested in the company’s inhouse test facility, including load and type testing.

Menzel’s Ex p motors were named the Product of the Year in the 2023 AEMT Awards.

Product website: https://www.menzel-motors.com/pressurized-exp-motors-zone1-operation/

Further information:
Menzel Elektromotoren GmbH
www.menzel-motors.com

At the Expomin trade fair, Menzel Elektromotoren (German pavilion, booth #9-C05) will present its motor range for the mining industry and capability to answer special customer requirements quickly and flexibly. The family-run German manufacturer supplies mines worldwide with large-scale electric motors for conveyors, fans, mills and crushers: high, medium and low-voltage motors, induction motors with slipring rotors up to 15 MW and with squirrel cage rotors up to 25 MW as well as DC motors up to 2 MW. Menzel specializes in customized motor construction and fast supply of replacement motors. The manufacturer’s standard motor series have excellent mechanical and thermal properties, which ensure efficient, low-maintenance operation and long lifespans. Menzel also has one of the largest stocks of motors and accessories, which experienced motor engineers quickly adapt for urgent orders. Special dimensions, electrical properties, cooling types, protection degrees or extreme load characteristics are no problem. Designing its drives, Menzel also observes the climatic locations at the customer’s site.

Menzel references: www.menzel-motors.com/references

Further information:
Menzel Elektromotoren GmbH
www.menzel-motors.com

Menzel Elektromotoren has designed and manufactured three powerful 6600 V squirrel cage motors as integral components for pit fans. The customer specified cylindrical motor casings as compact as possible. The greatest challenge was to implement the required rated power of 1700 kW in cylindrical casings. Menzel therefore designed fin-cooled motors (cooling type IC 411) in frame size 630, an extremely unusual design for motors this large (Figure 1).

The manufacture is complex but the result is optimal for the constricted installation conditions. In order to save additional space, all connection cables are routed out of the motors and the terminal boxes are mounted outside the fans. Since the driven fan wheels are mounted directly on the motor shafts, the motor bearing must compensate additional high loads: radial loads up to 20700 N and axial loads up to 27000 N. For the required bearing service life of 100,000 hours, Menzel implemented a special rolling bearing setup. In addition, the motors have a second shaft end for a holding brake. The three-phase squirrel cage motors are designed for operation on a frequency converter (duty type S9) with speed changes and reversal of the rotation direction. This allows the pit fans not only to ventilate the mine, but also to extract dangerous firedamp if necessary.

Further information:
Menzel Elektromotoren GmbH
www.menzel-motors.com