Motor Starting
Motor starting studies evaluate system voltage dips, motor acceleration torque, starting duration, and running load stability during the startup of large medium-voltage and low-voltage electric motors. MEPCO identifies voltage sag mitigation strategies and verifies starting methods to prevent motor stall, contactor drop-out, and generator tripping.
Figure 1: MEPCO electrical engineers evaluating medium-voltage motor control center (MCC) starting performance.
Technical Scope & Engineering Capabilities
MEPCO Engineering Projects brings specialized domain knowledge, rigorous modeling standards, and practical site experience to every assignment. Our scope covers:
- Dynamic Voltage Sag Analysis: Calculating transient voltage dips at the motor terminals, auxiliary buses, and Point of Common Coupling (PCC) during motor startup.
- Motor Acceleration Simulation: Evaluating motor speed vs. torque, acceleration time, load torque curve, and thermal withstand limit curves under reduced voltage conditions.
- Starting Method Optimization: Evaluating and comparing Direct-On-Line (DOL), Star-Delta, Auto-transformer, Soft Starter, and Variable Frequency Drive (VFD) configurations.
- Running Load Impact: Assessing the impact of motor inrush currents on already-running motors, sensitive electronic equipment, and lighting networks.
- Generator-Fed Starting: Evaluating voltage and frequency response when large motors are started on emergency diesel generator supplies.
Software Platforms & Computational Tools
Primary Tool: ETAP Dynamic Motor Acceleration & Starting Analysis Module.
Simulation Modes: Static Motor Starting (locked-rotor impedance method) and Dynamic Motor Acceleration (torque-slip curve and mechanical load model).
Applicable Standards & Grid Codes
Standards: IEEE 399 (Brown Book), NEMA MG-1 (Motors and Generators), IEC 60034-12 (Starting performance of single-speed three-phase cage induction motors).
Methodology & Project Delivery Workflow
Our engineering delivery aligns with MEPCO’s structured 6-stage project execution framework, ensuring quality throughout input verification, design modeling, and client handover:
- Stage 01 — Scope & Criteria Definition: Establish study boundaries, utility tie-in data, single-line diagrams, and client objectives.
- Stage 02 — Data Audit & Modeling Assumptions: Collect, verify, and validate manufacturer datasheets, impedance tolerances, and site operating configurations.
- Stage 03 — Simulation Model Development: Build detailed, validated mathematical digital models in specialized power software.
- Stage 04 — Computational Analysis & Verification: Execute base-case and contingency scenarios, conducting rigorous internal peer reviews.
- Stage 05 — Client Review & Approval: Present study findings, address technical comments, and participate in technical clarification sessions.
- Stage 06 — Final Handover: Deliver formal certified engineering reports, executive summaries, and native simulation model files.
Figure 2: Medium-voltage motor feeder switchgear with soft starter and protection interfaces.
Completed Project References (From MEPCO Profile)
Selected project assignments delivered by MEPCO demonstrating our technical execution and regional client trust:
| Project Name | Client / Authority | Location | Tools / Mode | Scope Executed |
|---|---|---|---|---|
| SPCO (North & South) Plant | Saudi Chevron (S-Chem) | Saudi Arabia | ETAP | Dynamic Motor Starting Analysis for heavy process compressor and pump induction motors. |
| JCP Plant | Saudi Chevron (S-Chem) | Saudi Arabia | ETAP | Motor Starting & Acceleration Studies under multiple operating configurations. |
| SCP Plant | Saudi Chevron (S-Chem) | Saudi Arabia | ETAP | Large MV Induction Motor Acceleration and System Voltage Recovery Analysis. |
| GAS-Jubail Industrial Plant | National Industrial Gases Company | Saudi Arabia | ETAP | Process Motor Starting and Voltage Dip Mitigation Study. |
| Air Liquide Industrial Plant | Air Liquide | Egypt | ETAP | Industrial Gas Compressor Motor Starting and Bus Voltage Drop Evaluation. |
Key Engineering Deliverables & Outputs:
- Motor Acceleration Study Report with transient voltage and current profiles vs. time.
- Motor Speed vs. Torque Acceleration Curves compared against load torque requirements.
- Voltage Drop Summary Sheets at motor terminals and upstream distribution buses.
- Starting Method Comparison Matrix and Soft Starter / VFD sizing recommendations.
- Thermal Stall Withstand Verification Curves.
Inquire About This Service
Contact MEPCO’s engineering team for technical proposals, study scope definition, or project consultations:
Email: m.khaled@mepco-tds.com | Phone: +20 11 2696 7082 | HQ: 5 Al-Ibrahimia Street, Cairo, Egypt