Basic Information
Product Description
1. Overview: Modular Slip-Ring Motors (NMK Series)
The NMK series modular slip-ring motors are engineered specifically for heavy-load inertia applications. They are the ideal solution for systems requiring high starting torque combined with low starting current. These motors are especially suitable for demanding environments such as mill drives or situations where network power conditions are weak.
Key Benefits:
-
Reduced Mechanical Stress: Minimizes mechanical stress during startup, significantly extending the lifetime of both the motor and the driven equipment.
-
Maximized Availability: Provides high torque over the entire speed range, ensuring reliable continuous operation.
Typical Applications:
-
Mining & Cement: Mills, crushers, fans, and conveyors.
-
Water Industry: Reliable pumping solutions.
-
Petrochemical Industry: Safe-area pumps, compressors, and mixers.
Design & Customization:
NMK slip-ring motors are available in shaft heights ranging from 400 to 710 mm, with standard cooling and protection combinations of IC611/IP55 and IC81W/IP55. Rated power reaches up to 10,000 kW.
The motors feature a robust welded steel frame. The slip ring unit (SRU) can be supplied with permanent contact brushes or brush-lifting gear. In both configurations, the slip rings are enclosed in a separate housing at the N-end, isolated from the main motor frame. A Liquid Resistance Starter (LRS) is also available upon request.
Note: While this catalog highlights typical technical data for 6kV and 11kV at 50Hz (4, 6, and 8-pole configurations), our complete product scope covers 60Hz options, pole numbers up to 16, and voltage ratings up to 13.8kV. Please contact us for detailed technical data and customized configuration solutions.
2. Mounting Arrangements
The standard mounting arrangements for NMK motors are:
-
Code I: IM B3 (Horizontal foot-mounted)
-
Code II: IM 1001
-
Other mounting options, such as IM1002, are available upon request.
3. Enclosure and Cooling Systems
Standard cooling and protection combinations for NMK motors are IC611/IP55 and IC81W/IP55. Other cooling methods (e.g., IC616, IC86W) can be customized upon request.
-
IC611/IP55 (Air-to-Air Cooling):
Features a fully enclosed air-to-air heat exchanger mounted on the motor. Shaft-mounted fans are fitted both inside the motor frame and the slip ring housing, as well as outside the casing, to supply independent internal and external cooling circuits. The motor is fully protected against dust and splashing water from any direction.
-
IC81W/IP55 (Air-to-Water Cooling):
A totally enclosed design featuring machine-mounted and SRU-housing-mounted air-to-water heat exchangers. A shaft-mounted fan inside the casing supplies the internal cooling circuit. Like the IC611 design, it offers IP55 protection against dust and splashing water from any direction.
4. Packaging
-
Standard Export Packaging: Seaworthy plywood or wooden fumigation-free packages.
-
Transport: Fully suitable for long-distance transportation by sea or land.
5. Warranty Policy
-
Standard Warranty: 12 months after successful commissioning, or 18 months after delivery, whichever comes first.
-
Extended Warranty: Extended warranty periods are available. Please contact us for further details and customized terms.
