The Drive Solution for Tooth Roll Crushers: Wheatstone Flameproof Mining Servo Motor

Tooth roll crushers are widely used in coal mines, mineral processing plants, and aggregate production facilities to reduce large coal and rock lumps to sizes suitable for transport. The crushing process generates significant mechanical shocks and vibrations due to uneven hardness and random interbedded rock layers, with instantaneous impact loads reaching up to 3× the rated torque of the drive motor [8†L7-L8].

In tooth roll crushers, drive motors are typically arranged in independent dual-motor configurations, each driving one crushing roll. Motor power ratings in this application commonly range from 55 kW to 400 kW, coupled with gearboxes that reduce speed to 20–60 rpm while multiplying torque by up to 150 times [8†L5-L7].

WHEATSTONE Flameproof Mining Servo Motors offer a purpose-engineered solution for this demanding application, delivering 3× peak overload capability, wide speed control range, and compliance with international hazardous area certifications including IECEx, ATEX, and CCCEx.

Three Key Performance Requirements for Crusher Drive Motors

① High Overload Capacity – When the crushing rolls encounter hard nodules or rock interlayers, torque demand rises instantaneously. The motor must withstand these transient peaks without stalling or overheating, requiring sustained overload performance well above rated torque.

② Wide Speed Regulation Range – Rotational speed of the crushing rolls must be adjustable to match material hardness and target output particle size. Low-speed, high-torque operation is required for hard materials, while higher speeds can be applied for softer feeds.

③ Frequent Start-Stop with Fast Dynamic Response – Production lines start and stop regularly, and the crusher system requires rapid dynamic response to adapt to material feed variations. Motor dynamic performance directly influences overall system throughput.

WHEATSTONE Flameproof Mining Servo Motor – Technical Advantages

1. 3× Peak Overload Capacity for Impact Handling

Through optimized electromagnetic design and high-grade magnetic materials, WHEATSTONE servo motors achieve a peak torque of 3 times the rated torque [15†L15-L16]. This capability prevents motor stalling during shock loading and ensures continuous crusher operation when hard material nodules are encountered. The motor incorporates a low-inertia rotor design for rapid torque build-up, and a peak torque envelope that meets the 5–7× start-up torque multiplier demands typical of mining extraction machinery [16†L15-L16][17†L21-L22].

1. Wide Speed Range from 1 to 3000 rpm

Hard material requires low-speed, high-torque crushing; softer material can be processed at higher speeds for increased throughput. WHEATSTONE servo motors maintain stable operation across a full 1–3000 rpm range while delivering rated torque at low speeds – eliminating the need for additional speed reduction components across different process stages [15†L17-L18].

1. Millisecond-Level Dynamic Response for Frequent Start-Stop

The motor features a short mechanical time constant, yielding rapid acceleration from zero speed to rated speed – enabling the fast response required for production line start-stop cycles [15†L18-L19]. When the control system detects foreign material or overload, it can initiate an emergency stop or reverse within milliseconds, protecting both the crusher and the drive motor.

1. Flameproof Enclosure (Ex d I Mb / Ex d IIB T4 Gb) with IP66 Protection

WHEATSTONE flameproof mining servo motors are certified for use in hazardous atmospheres in accordance with international and Chinese standards:

Coal mine atmospheres (methane gas): Ex d I Mb, designed to GB 3836 series standards (China) and equivalently tested to IEC 60079-1

Non-coal gas atmospheres: Ex d IIB T4 Gb, gas group IIB with temperature class T4

Dust atmospheres: Ex tb IIIC T130℃ Db for combustible dust environments [17†L14-L16]

The flameproof enclosure is constructed from high-strength cast steel or cast iron with wall thickness optimized by finite element analysis. Flameproof joint surfaces are machined to a surface roughness of Ra ≤ 6.3 μm, and joint clearances strictly conform to IEC 60079-1 and GB 3836.2 requirements, ensuring that any internal explosion is contained and the flame is cooled as it passes through the flameproof gap [17†L16-L17].

Environmental protection: The motor is rated IP66 as standard, with double-sealed terminal boxes and explosion-proof cable glands. The enclosure is coated with a heavy-duty anti-corrosion finish capable of withstanding underground humidity (≥90% RH), salt spray, and mildly acidic mine water conditions. For highly aggressive environments, a 316L stainless steel enclosure and A4-80 stainless steel external fasteners are available as options [17†L18-L20].

Electrical insulation: H-class (180℃) insulation system with vacuum pressure impregnation (VPI) processing fills all winding voids with solvent-free resin, eliminating partial discharge pathways. Under full load conditions, winding temperature rise is maintained within 80K, providing a significant operational safety margin [17†L20-L21].

1. Compliance with International Hazardous Area Certification Systems

WHEATSTONE flameproof mining servo motors are designed and tested to meet the following international hazardous area certification requirements:

IECEx Certification – Based on the IEC 60079 series of standards. The IECEx system is an international mutual recognition framework covering 46 member countries. IECEx certification serves as a foundational entry requirement for multiple national markets. Certificate validity is five years with annual surveillance audits [9†L8-L9][10†L7-L8].

ATEX Certification (EU) – Compliant with the EU CE marking system under Directive 2014/34/EU and the EN 60079 series of standards. ATEX is mandatory for products placed on the market within the European Union for use in potentially explosive atmospheres [9†L5-L7].

CCCEx Certification (China) – Certified to GB 3836 series standards which are technically equivalent to IEC 60079. WHEATSTONE motors have obtained flameproof certification from the China National Quality Supervision and Testing Centre for Explosion-Protected Electrical Products (CQST) [6†L4-L6][6†L11-L12].

North America (UL / CSA) – Available upon request to UL 1203 (ANSI/UL standard) for the US and CSA C22.2 No. 30 for the Canadian market, with area classifications to Class I Division 1 & 2 and Class II Division 1 & 2 configurations for gas, vapor, and dust hazardous locations.

EAC 012 (Eurasian Customs Union) – Available upon request for the markets of Russia, Belarus, Kazakhstan, Armenia, and Kyrgyzstan under Technical Regulation TR CU 012/2011, with standards equivalent to IEC 60079 and certificate recognition among member states [9†L12-L14].

Field Validation

WHEATSTONE flameproof mining servo motors have been deployed in tooth roll crusher installations across multiple coal mining and mineral processing operations. Under long-term high-impact and frequent start-stop operation, the motors demonstrated 3× peak overload handling and stable speed regulation from 1 to 3000 rpm – matching the high shock tolerance and multi-stage speed adjustment requirements of the tooth roll crusher application, resulting in improved system stability and increased throughput.

Typical Motor Specifications (Representative Model)

About WHEATSTONE

Jiangsu WHEATSTONE Electromechanical Technology Co., Ltd. has 20 years of expertise in specialized control motors. The company is ISO 9001 and IATF 16949 certified, with flameproof motor products certified to explosion-proof standards, CE, and RoHS. Applications include mining underground extraction equipment, tooth roll crushers, conveyor machinery, high-speed rail, and new energy vehicles [18†L14-L17].