ZSN4 Series DC Motors for Cement Rotary Kilns – Model Designation
      Taking the SIMO ZSN4 series DC motor model ZSN4-280-11B as an example: “Z” denotes DC motor; “SN” denotes cement rotary kiln application; “N4” indicates the fourth series design; “280” denotes frame center height (mm); the first “1” denotes armature core length code; the second “1” denotes end shield code; “B” denotes with compensating winding.
      Note: Frames 315 and 355 are supplied with compensating windings by default; thus, the suffix “B” may be omitted.
            Numerals “1” and “2” denote short and long end shields, respectively.
            Armature core length codes, in descending order of length, are: 3, 2, 1, 09, 08, 07.

Overview of ZSN4 Series DC Motors for Cement Rotary Kilns
      The SIMO ZSN4 series DC motors are a specialized product line developed based on the Z4 series DC motors, specifically optimized for the operational characteristics of cement rotary kiln loads.
      The ZSN4 series SIMO DC motors feature an octagonal frame structure offering high stator space utilization. The stator yoke is laminated to withstand pulsating currents and high current slew rates. When powered by a three-phase fully-controlled bridge rectifier, no external smoothing reactor is required. The motors employ Class F insulation, enabling higher power ratings. Designed to meet the specific requirements of cement rotary kilns, these motors deliver a starting torque up to 2.5 times the rated torque. A pipe-ventilation cooling system ensures safe and reliable operation in harsh, high-dust environments.

Performance Specifications of ZSN4 Series DC Motors for Cement Rotary Kilns
      1. The motor shall operate continuously at rated output under the following conditions:
      1.1 Altitude not exceeding 1000 m.
      1.2 Inlet cooling medium temperature not exceeding 40 °C.
      1.3 Duty type: continuous duty (S1).
      1.4 Armature and field circuits powered by static rectifier supplies or DC generator sets.
      1.5 For pipe-ventilated motors, airflow and static pressure must comply with the table below. The air inlet is located on the non-commutator-side end shield.

Frame Size	Airflow (m³/h)	Static Pressure (Pa)
ZSN4-225	2880	1400
ZSN4-250	3000	1400
ZSN4-280	4000	1600
ZSN4-315	4680	1600
ZSN4-355	5200	1600

      2. Motor insulation class: F.
      3. Rated armature voltage: 440 V; optional voltages include 400 V, 220 V, or others per customer request. Low-armature-voltage operation enables constant-torque speed control. Under continuous armature current conditions, the minimum speed can reach 20 r/min while maintaining rated torque smoothly.
      4. Rated field voltage: 180 V; other field voltages available upon request. To ensure reliable field circuit insulation, a discharge resistor must be connected across the field winding terminals when interrupting the field circuit, preventing damaging self-induced EMF. For field voltages of 180–220 V, the resistance value should be approximately seven times the cold-field-winding resistance; for 320–370 V, approximately five times.
      5. Efficiency values listed in technical data tables refer to rated power, rated voltage, and rated speed, including field losses but excluding power consumed by auxiliary ventilation equipment.
      6. The ZSN4-225 motor does not incorporate a compensating winding but includes a series field winding.
      7. Motors are provided with a grounding terminal marked accordingly.
      8. All performance specifications comply with national standard GB755–87 “Basic Technical Requirements for Rotating Electrical Machines” and industry standard JB6316–92 “Technical Specifications for Z4 Series DC Motors”. Compliance with IEC 34-1 (International Electrotechnical Commission) is also available upon request.

Ordering Instructions for ZSN4 Series DC Motors for Cement Rotary Kilns
      1. Prior to ordering, consult the SIMO Motor product catalog to confirm required model, specifications, etc. Specify in the purchase contract: motor model, power rating, voltage, speed, excitation method, excitation voltage, communication interface (if applicable), and mounting configuration. Refer to Table 3 for technical data and Figures 1–5 for outline and mounting dimensions.
      2. Special requirements—e.g., dual shaft extensions, reversed terminal box orientation, or integrated tachogenerators—must be explicitly stated in the contract.
      3. For models or specifications not listed in this catalog, or for additional special requirements, contracts and technical agreements shall be executed upon mutual agreement between both parties.