Explosion-Proof Servo Motors for Pyrotechnic Equipment: How Wheatstone Safeguards Precision and Safety in Hazardous Production Lines

In the production of propellants, explosives, detonators, and fuzes, every process—from raw material mixing and pressing to filling, inspection, and transfer—demands extreme safety measures. Any electrical spark, mechanical friction overheating, or electrostatic accumulation could lead to catastrophic consequences. The motors driving these critical operations must not only provide high dynamic response and positioning accuracy but also inherently eliminate all potential ignition sources. Jiangsu Wheatstone has developed a full series of explosionproof servo motors for the pyrotechnics industry, combining flameproof enclosures, brushless electronic commutation, widetemperature lubrication, and intelligent condition monitoring—delivering safe, reliable, and precise power for automated pyrotechnic production lines.

I. Four Essential Requirements for Motors in Pyrotechnic Production

1. Complete Elimination of Electrical SparksStandard motors, especially brushed types, generate sparks during commutation—strictly prohibited in pyrotechnic environments. Explosionproof servo motors use electronic commutation, eliminating carbon brushes and commutation sparks at the source.

2. Strict Surface Temperature ControlMotor surface temperatures may rise during prolonged operation or stalling. Pyrotechnic materials are highly temperaturesensitive, so motors must ensure that surface temperatures remain below the autoignition point of the surrounding materials.

3. Extremely High Positioning AccuracyFilling and pressing operations require tight tolerances on charge weight. The motor driving the filling screw or pressing punch must achieve micronlevel displacement control.

4. Frequent StartStop and LowSpeed CapabilityPyrotechnic production is often batchoriented, requiring frequent starting, stopping, reversing, and smooth torque at very low speeds to avoid mechanical shock.

II. Core Technical Advantages of Wheatstone ExplosionProof Servo Motors

1.Intrinsically Safe Flameproof Construction

Wheatstone motors feature II 2G Ex db IIC T4 Gb flameproof enclosures that fully contain internal components capable of generating sparks or arcs. Precisionmachined flame paths (surface roughness ≤6.3 μm Ra) ensure that, even in the event of an internal explosion, flames are cooled and extinguished before reaching the external atmosphere. Ex tb IIIC T130℃ Db dust ignition protection is also available for pyrotechnic dust environments.

In detonator drilling equipment and other defense applications, Wheatstone’s II 2G Ex db IIC T4 Gb rating ensures production safety and prevents accidents. In 2025, King Explorer received a patent for a fully automatic coldcutting case opener for pyrotechnic metal boxes, which uses full explosionproof servo motor control for automatic feeding, positioning, and cold cutting—eliminating risks at the source.-

2.Brushless Electronic Commutation – Zero Spark Operation

Permanent magnet synchronous servo technology eliminates rotor windings; the stator is commutated electronically by the drive without any mechanical contact. This completely removes carbon brush sparks and commutator wear, eliminating the ignition source at its root.

3.HighPrecision ClosedLoop Control for MicronLevel Positioning

A 23bit absolute encoder (approx. 8.38 million pulses per revolution) combined with vector control achieves position accuracy of ±0.005°, translating to micronlevel linear displacement when paired with a gearbox or lead screw. In automatic pyrotechnic pressing machines, Wheatstone motors driving precision screws control charge weight deviation within ±0.5%. The Automation Research Institute’s explosionproof servo press technology, using closedloop control, has solved common problems in pyrotechnic pressing: low pressure accuracy, poor stability, low yield, and safety hazards. Over 150 units are expected to be deployed, generating direct economic benefits exceeding 50 million RMB.-

4.WideTemperature Lubrication and Low Thermal Design

Perfluoropolyether (PFPE)-based hightemperature grease provides an operating range of -40°C to +200°C, resisting volatilization and carbonization under frequent startstop cycles. Optimized electromagnetic design reduces iron and copper losses, keeping motor body heat generation low. The flameproof housing’s cooling fins maintain surface temperature below T4 class (≤135°C), meeting pyrotechnic safety standards.

5.BuiltIn Temperature and Vibration Monitoring

Optional PT100 winding temperature sensors and vibration sensors enable realtime health monitoring. If temperature or vibration exceeds preset thresholds, the control system can alarm or shut down, enabling predictive maintenance and preventing equipment operation with potential faults.

III. RealWorld Application Cases

Case 1: Rotary Indexing Table for Detonator Assembly

A detonator assembly line required frequent indexing of workstations for shell feeding, filling, and pressing, with positioning time ≤0.5 seconds. A Wheatstone 90EX explosionproof servo motor (750W, 2.4Nm) directly driving a cam indexer, paired with a 23bit absolute encoder, achieved positioning accuracy of ±0.02° and reduced cycle time from 1.2 seconds to 0.8 seconds per piece. The system has operated for two years without failure or safety incidents.

Case 2: Screw Drive for Automatic Explosive Weighing and Filling Machine

A pyrotechnic facility required filling explosive powder into cartridges with an accuracy of ±0.1g, with screw speed precisely adjustable from 10 to 200 rpm. A Wheatstone 60EX explosionproof servo motor (400W, 1.3Nm) directly connected to the metering screw, with closedloop speed and torque control, achieved filling accuracy of ±0.08g—exceeding national standards. The motor operates reliably in a dust explosionproof environment with a measured surface temperature of only 78°C.-

Case 3: Main Drive for Fuze Automatic Screwing Machine

A fuze assembly line required tightening of housings and internal components to a specified torque with ±3% error, and the process must be shockfree. A Wheatstone 80EX explosionproof servo motor (750W, 2.4Nm) with a torque sensor, operating in torque control mode, achieved torque accuracy of ±2% and a pass rate of 99.8%, with smooth startstop and no overshoot.

Case 4: Fully Automatic ColdCutting Case Opener for Pyrotechnic Metal Boxes

King Explorer’s fully automatic coldcutting case opener is used for automatic feeding, positioning, and cold cutting of pyrotechnic metal boxes. Controlled by full explosionproof servo motors with screw and gear power transmission, it achieves automatic material feeding, positioning, and cold cutting—automating the lidcutting process, eliminating manual cutting, ensuring operational safety, and improving product consistency and safety.

IV. Wheatstone ExplosionProof Servo Motor Selection Guide for Pyrotechnic Equipment

Series	Frame (mm)	Power (kW)	Rated Torque (Nm)	Peak Torque (Nm)	Explosion Protection	Ingress	Recommended Applications
60EX	60	0.2-0.75	0.6-2.4	1.8-7.2	II 2G Ex db IIC T4 Gb	IP65/IP66	Small filling machines, metering screw drives
80EX	80	0.75.2	2.4-4	7.22	II 2G Ex db IIC T4 Gb	IP65/IP66	Fuze screw drivers, pressing punch drives
90EX	90	1.0-2.3	3.3-7.3	9.9-21.9	II 2G Ex db IIC T4 Gb	IP65/IP66	Detonator assembly indexing tables, indexing mechanisms
110EX	110	2.3-4.0	7.32.7	21.9-38.1	II 2G Ex db IIC T4 Gb	IP66	Large pressing machines, mixing equipment
130EX	130	4.0-7.5	12.7-23.9	38.1-71.7	II 2G Ex db IIC T4 Gb	IP66	Heavyduty pressing presses, largecharge pressing

V. Conclusion

In the pyrotechnics industry—a true “restricted zone”—equipment safety and reliability are paramount. Jiangsu Wheatstone explosionproof servo motors deliver safety with Ex d IIB T4 Gb flameproof construction, precision with ±0.005° positioning accuracy, and durability with 3× overload capacity—providing reliable power across the entire pyrotechnic production process, from detonator assembly to explosive filling, fuze screwing to coldcutting automation. From detonator assembly to explosive weighing, from fuze screwing to coldcutting automation, Wheatstone motors are quietly guarding every process in pyrotechnic production.

For explosionproof servo motor selection needs for pyrotechnic production lines or defense and industrial explosive applications, contact the Wheatstone technical team for fullprocess support – from explosion protection assessment and motor selection to onsite commissioning.