siemens
Siemens SIMOTICS M 1PQ8 Slip-Ring Induction Motor
Model: 1PQ8357-4AF90-Z
4-hour response · Pricing in SAR · Delivery across all KSA regions
1PQ8357-4AF90-Z — Siemens SIMOTICS M 1PQ8 Slip-Ring Induction Motor
The Siemens SIMOTICS M 1PQ8 is a wound-rotor (slip-ring) induction motor covering 75 kW to 3150 kW at 380–6600 V, purpose-designed for applications that demand high starting torque, reduced starting current, or controlled acceleration — characteristics that squirrel-cage induction motors and even variable speed drives cannot always match cost-effectively for very large, high-inertia loads. The slip-ring design inserts external rotor resistance via carbon brushes bearing on three slip rings, allowing the starting torque to reach 200–250% of rated torque while limiting starting current to as low as 150% FLC — a critical advantage in industrial facilities where utility supply capacity limits starting kVA on large motors connected at 6.6 kV or 11 kV.
The 1PQ8 features cast iron construction to IEC frame sizes 355–630, Class F insulation, and robust slip ring and brush gear assembly with accessible maintenance covers. The rotor circuit is designed for connection to external liquid resistance starters (LRS) or stepped metal resistance banks, providing precise acceleration ramp control that is adjustable per application without software changes. Optional forced ventilation (IC511 or IC611) cooling increases the thermal capacity for short-time or duty-cycle loaded applications such as crane hoist motors and rolling mill drives. The motor is available with encoder mounting for speed feedback and with PT100 thermistor protection in windings and bearings.
In Saudi Arabia, the SIMOTICS M 1PQ8 slip-ring motor KSA remains the preferred starting method for large crusher and ball mill drives at phosphate mining operations in Wa'ad Al-Shamal and mineral processing plants in Ras Al-Khair Industrial City. Saudi Cement and YACCO cement plants in the Kingdom specify slip-ring motors for raw mill main drives where the high breakaway torque requirement exceeds what a direct-on-line squirrel-cage motor can achieve. Port crane and hoist operators along the Red Sea and Arabian Gulf coasts use the 1PQ8 for grab crane and container crane drives where the controlled acceleration characteristic prevents load swing and reduces mechanical stress on wire ropes and gearboxes.
Razz Middle East supplies SIMOTICS M 1PQ8 motors with matched liquid resistance starters and stepped resistance banks, providing complete starting system packages with full IEC test documentation, motor performance curves, and on-site commissioning support across Saudi Arabia.
Technical Specifications
Full specifications for the 1PQ8357-4AF90-Z
- Power Range
- 75–3150 kW
- Voltage
- 380–6600 V AC, 3-phase
- Rotor
- Wound rotor with slip rings and brush gear
- Cooling
- IC411 or IC511/IC611 forced vent
- Frame
- IEC 355–630 cast iron
- Insulation
- Class F (155°C)
- Enclosure
- IP54 / IP55
- Starting
- External LRS or stepped resistance
- Standard
- IEC 60034-1, IEC 60034-12
- Options
- Encoder mounting, PT100 windings/bearings
Key Features & Benefits
- Wound rotor with external rotor resistance enables starting torque of 200–250% rated torque while limiting starting current to 150% FLC — critical for large crushers and mills at Saudi mining and cement sites with limited supply kVA.
- External resistance starter connection via slip rings allows acceleration time and torque profile to be adjusted per application by changing resistor values, providing flexibility that software-only solutions cannot match for very large inertia loads.
- Rated voltage range from 380 V to 6600 V in a single motor frame family allows the same motor design to be used at MV distribution voltage levels, avoiding the cost of a dedicated MV VFD for fixed-speed or limited-range applications.
- Robust carbon brush and slip ring assembly with large contact area and accessible maintenance covers allows in-service brush replacement without motor disassembly — reducing planned maintenance downtime at continuous-process Saudi facilities.
- Optional forced ventilation (IC511, IC611) cooling increases thermal capacity for duty-cycle and short-time loaded applications such as crane and hoist motors, allowing a smaller motor frame to handle the thermal demands of intermittent duty.
- PT100 temperature sensors in stator windings and rotor slip ring housing provide continuous thermal monitoring, protecting the motor against the consequences of external resistance controller faults or stalled starts.
- IEC 60034-12 starting category S, D, H available to match the starting requirements of different crusher, mill, and compressor load curves, ensuring motor thermal withstand during the extended start times of high-inertia loads.
Industrial Applications in Saudi Arabia
- Ball mill and SAG mill main drives at phosphate and mineral processing facilities in Wa'ad Al-Shamal and Ras Al-Khair, where starting torque requirements of 180–220% rated and 20–60 second acceleration times exclude squirrel-cage motor options.
- Primary and secondary crusher drives at Saudi mining operations, where the controlled acceleration of the slip-ring motor protects crusher liners and ore feed conveyor mechanical systems from high-inertia impact loading.
- Raw mill and cement mill main drives at Saudi Cement, YACCO, and Al Jouf Cement plants, where breakaway torque requirements for grinding media exceeding 200% rated torque mandate slip-ring motor starting.
- Container and bulk cargo crane drives at Dammam, Jubail, and Jeddah ports, where controlled acceleration reduces load swing on long wire ropes and gearbox shock loading compared to DOL squirrel-cage starts.
- Kiln trunnion drive motors at cement and lime plants, where the external resistance provides precise low-speed starting capability for controlled kiln shell warm-up procedures during commissioning and restarts.
- Large induced draught and forced draught fan drives at power stations and petrochemical facilities, where the reduced starting current protects the MV bus from voltage dip during starts of motors exceeding 2 MW.
- Marine and offshore lifting equipment drives at Saudi Aramco offshore jackets and IKTVA-qualified Saudi offshore service vessels, where the slip-ring motor's precise speed control via external resistance suits variable-speed crane duty.
Industrial Supplier in Saudi Arabia
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