Modular slip ring motors

The operating conditions for slip ring motors in raw material extraction and preparation are particularly demanding. Motors that drive mills, breakers, or fans, for example, in a cement works, are always exposed to heavy loads due to dust, heat, and vibrations and must also provide exceptional mechanical performance at the same time.

Slip ring motors in the IC 611 cooling class dominate within applications in the cement industry nowadays, which means motors with attached air-air cooler. A few motors, particularly large mill drives, are also designed in the IC 01 cooling class, meaning that they are open circuit-cooled.

The IC 6111 cooling class with air-air heat exchanger that is typical in the cement industry has a major advantage regarding its basic design in that neither cooling water nor a particularly clean environment is necessary. However, regular monitoring and visual checks of the motor are necessary. Frequent checks should take place to ensure that the cooling pipes are not clogged up so that heat dissipation is prevented. This would lead to the motor overheating and the alarm for temperature monitoring being triggered.

MENZEL modular slip ring motors in the MEBSSL series are characterized by a compact design, small dimensions, and low weight. It provides you with complete flexibility and can be delivered in IM B3 and IM v1 construction types pursuant to IEC 60034-7. Special designs that deviate from these can be implemented for you on request at any time.

The modular electric motors have a welded steel housing with integrated footplates. The housing design guarantees maximal torsion resis­tance and optimal cooling. The housing and laminated stator core are processed with low tolerances, which results in particularly low thermal resistance.

Pursuant to the customer’s requirements, the motors are provided with a “right” or “left” terminal box. Special terminal boxes (e.g. with phase separators, special dimensions, etc.) or single-phase plug-in systems are available on request. The terminal boxes can be rotated by 4 x 90°.

Just like all of our three-phase asynchronous motors, MENZEL slip ring motors are produced pursuant to the European Standards IEC 60034 and EN 60034, VDE, DIN and ISO in their current form.

The slip ring motors in the MEBSSL series are designed within the IP 55 protection class. Higher protection classes can be realized at any time.

For insulation, the humidity-protected motor winding is designed to be in thermal class "F" and is produced using the VPI (vacuum pressure impregnation) method. The thermal utilization of our slip ring motors takes place within thermal class “B”. This results in creation of a reserve capacity and the motors do not age as quickly. The insulation on the winding is capable of withstanding the highest mechanical stress, so that restarting against a residual field of 100% following a power failure is possible at any time.

The MEBSSL slip ring motors are designed with high-quality, lubricated rolling bearings incl. lubrication devices. Depending on the application of the motor, we can also deliver custom bearings if desired such as, for example, spherical roller bearings with shredder drives in order to be able to absorb forces arising on the input side within the motor bearing.

Designs with self-lubricated or externally lubricated slide bearings are also available on request. Only high-quality bearings and lubricants from renowned manufacturers are used in the production of our electric motors.

Our MEBSSL modular slip ring motors in the IC 616, IC 616 and IC 666 cooling classes have extremely low vibration values and fulfill the requirements of vibration level N (normal) pursuant to EN 60034-14. The corresponding vibration measurement is carried out in no-load operation, at the nominal voltage and nominal frequency.

The balance quality of the motors is essentially “half-key”, whereas it can also be changed to "full-key" on request.

The compact design of our modular motors with slip ring rotor also ensures extremely low noise emissions. The vibration measurement is also carried out in no-load operation, at the nominal voltage and nominal frequency.

The default paint work on our motors corresponds to the “moderate” climate group pursuant to DIN 600 721-2-1. Several special paints can be delivered on request. The default color is RAL 1016 "sulfur yellow". Special colors deviating from this can be individually realized in our in-house paint shop at any time.

MENZEL MEBSSL modular slip ring motors are typically designed for operation in ambient temperatures between -20°C and +40°C. Motor power must be reduced for higher ambient temperatures up to +60°C. Our team of engineers can calculate this for such special cases in line with your individual requirements. For ambient temperatures lower than -20°C, MENZEL can supply special shaft steel and reinforced standstill heaters on request.

The power rating specifications apply to operating mode S1 (i.e. long-term operation) at nominal voltage and nominal frequency, with an ambient temperature of 40°C and an installation altitude of 1,000 m above sea level. If the installation altitude varies, then a reduction in the power rating must be taken into consideration. With the nominal voltage, the slip ring motors have an overload capacity of up to two minutes with 1.5 times the nominal current.

MENZEL slip ring motors in the MEBSSL series are generally designed with temperature monitoring for the winding and bearing as well as mechanical SPM measurement taps for recording the vibration values:

• 6 x Pt100 resistance thermometers (RTD) in the stator winding
• 2 x Pt100 resistance thermometers (RTD) in the bearing chambers
• 2 x SPM measurement taps

The terminals of the resistance thermometers are implemented into a separate terminal box.

The motors are also equipped with standstill heating (230 V/1~) incl. a separate terminal box. Standstill heaters with deviating nominal voltages are also possible. In addition, we can deliver a wide range of additional accessories, sensors, and transmitters on request.