An International Power Quality Discussion Forum (IPQDF) Technical Resource
Introdução: Motors and Power Quality
Electric motors consume over 45% of global electrical energy. Their selection, operação, and characteristics directly impact power quality through:
- Starting currents (5-10x FLC for standard motors) – perIEC 60034-12 starting performance classifications
- Fator de potência (lagging for induction motors)
- Harmonic injection (VFD-driven motors) – seeIEC 61000-2-4 compatibility levels
- Voltage dip sensitivity – measured perIEC 61000-4-30 Class A or S methods
- Efficiency compliance -IEC 60034-30-1 IE code classes (IE1 to IE5)
Understanding motor types is essential for designing robust electrical systems and mitigating power quality issues.
1. Motor Classification by Power Source & Application
flowchart LR A[Electric Motors] --> B[AC Motors] A --> C[DC Motors] A --> D[Universal Motors] B --> B1[Induction] B --> B2[Synchronous] B --> B3[Special Single-Phase] B1 --> B1a[Single-Phase] B1 --> B1b[Three-Phase<br>IEC 60034-12 Designs N, H, D] B3 --> B3a[Written-Pole<br>IEC 60034-1 Duty Types] B3 --> B3b[Rosenberg<br>Historical] B3 --> B3c[CSCR<br>IEC 60034-26] C --> C1[Brushed DC<br>IEC 60034-30-1 excludes] C --> C2[Brushless DC<br>BLDC - IEC 61800-9 PDS] style A fill:#e1f5fe,golpe:#01579b,curso de largura:2px style B fill:#fff3e0,stroke:#e65100,stroke-width:2px style C fill:#fff3e0,stroke:#e65100,stroke-width:2px style D fill:#fff3e0,stroke:#e65100,stroke-width:2px style B1 fill:#e8f5e8,stroke:#1b5e20,stroke-width:1px style B2 fill:#e8f5e8,stroke:#1b5e20,stroke-width:1px style B3 fill:#f3e5f5,stroke:#4a148c,curso de largura:1px
2. IEC Standards Framework for Motors & Qualidade da Energia Elétrica
Core Motor Standards
Qualidade da Energia Elétrica & Measurement Standards
Supply System Standards
3. Detailed Motor Analysis with PQ Considerations
A. DC MOTORS
B. AC MOTORS – The Industrial Workhorses
Induction Motors (Asynchronous)
Operating Principle: Rotor “chases” rotating magnetic field, always operating at slightly less than synchronous speed. PerIEC 60034-12, starting performance is classified by design letters:
| Design Letter | Starting Torque | Locked Rotor Current | Application | IEC Designation |
|---|---|---|---|---|
| N | Normal | Normal | Fans, pumps, general purpose | IEC 60034-12 Design N |
| H | High | Normal | High inertia loads (centrifuges) | IEC 60034-12 Design H |
| D | Very High | High | Punch presses, cranes | IEC 60034-12 Design D |
| N-E | Normal efficiency-optimized | Normal | Premium efficiency pumps | IEC 60034-12 |
| HE | High efficiency-optimized | Normal | High efficiency applications | IEC 60034-12 |
Single-Phase Induction Motors
| Tipo | HP Range | Starting Current | PQ Concern | IEC References | Aplicações |
|---|---|---|---|---|---|
| Split-Phase | 1/20 – 1/2 HP | 6-8x FLC | Low power factor | IEC 60034-1 duty S1 | Fans, blowers |
| PSC | 1/4 – 10 HP | 5-7x FLC | Capacitor failure modes | IEC 60034-26 unbalanced voltage | HVAC blowers |
| CSIR | 1/4 – 10 HP | 4-6x FLC | Start capacitor switching transients | IEC 61000-4-30 event detection | Compressors |
| ✅ CSCR | 1 – 25+ HP | 4-6x FLC | Dual capacitor PQ issues | IEC 60034-26 | Large compressors, irrigation pumps |
Three-Phase Induction Motors
IEC 60034-30-1:2025 now includesIE5 efficiency class with nominal efficiency values up to1000 kW .
C. Special High-Power Single-Phase Motors for Rural Applications
The Rosenberg Motor (Historical Solution)
Inventor: E.J. Rosenberg & Charles Proteus Steinmetz (DAR, 1920s)
The Rosenberg motor is a repulsion-induction motor with a unique inductor winding projeto. for retrofit projects it is replaced by modern solution such as Written-Pole or VFD + phase converter.
Power Quality Perspective (Outdated use modern solution):
- Advantage: Enabled high-power farming on limited single-phase grids
- Desafiar: Commutator arcing, brush maintenance, power factor variation
- IEC Context: Predates modern standards but aligns withIEC 60034-1 duty type S1 for continuous operation
Written-Pole Motor (Modern Solution)
Developer: Precise Power Corporation (1990s)
PQ Advantages:
- Starting Current: 2-3x FLC (vs. 6-8x standard)
- Voltage Dip Ride-Through: Superior to induction motors
- Grid Impact: Minimal startup disturbance on weak feeders
IEC Compliance:
- Duty type S1 perIEC 60034-1
- Ambient temperature rating perIEC 60034-30-1 (-30°C to +60°C)
- Altitude rating up to 4000m perIEC 60034-30-1 Nota 5
Aplicações: Standby generators, irrigation pumps (até 50 HP), off-grid systems
D. Synchronous & Specialized Motors
4. Power Quality Impact Comparison Table
| Motor Type | Starting Inrush | Fator de Potência | Conteúdo Harmônico | Voltage Sensitivity | IEC Standards for Mitigation |
|---|---|---|---|---|---|
| Standard Induction | 6-10x FLC | 0.85 atraso (full load) | Minimal (without VFD) | High (stalls at 80-85%) | IEC 60034-12 starting design |
| Written-Pole | 2-3x FLC | 0.92 atraso | Minimal | Low (rides through dips) | IEC 60034-1 duty S1 |
| BLDC with VFD | Limited by controller | Near unity (controlled) | High (5ª, 7ª, comutação) | Medium | IEC 61800-3 EMC IEC 61800-9-2 eficiência |
| CSCR | 4-6x FLC | 0.90-0.95 | Minimal | Medium | IEC 60034-26 unbalance |
| SynRM with VFD | Controlled | 0.98+ (optimized) | VFD-dependent | Low (controlled) | IEC 61800-9-2 PDS class |
Harmonic Compatibility Levels (IEC 61000-2-4)
| Harmonic Order | Class 1 (Sensitive) | Class 2 (Geral) | Class 3 (Industrial) |
|---|---|---|---|
| 3rd | 3% | 5% | 6% |
| 5ª | 3% | 6% | 8% |
| 7ª | 3% | 5% | 7% |
| 11ª | 3% | 3.5% | 5% |
| THD | 5% | 8% | 10% |
| Desequilíbrio | 2% | 2% | 3% |
5. Motor Selection Guide for PQ-Sensitive Applications
Consideration Matrix:
quadrantChart title Motor Selection for Power Quality x-axis "Poor Power Quality Tolerance" --> "Excellent Power Quality Tolerance" y-axis "Low Efficiency/Cost" --> "High Efficiency/Cost" "Written-Pole<br>IEC 60034-1": [0.8, 0.7] "SynRM + VFD<br>IEC 61800-9-2": [0.9, 0.9] "Standard Induction<br>IEC 60034-12 N": [0.3, 0.3] "PMSM<br>IEC 60034-30-1 IE5": [0.7, 0.95] "CSCR<br>IEC 60034-26": [0.5, 0.6] "BLDC<br>IEC 61800-1": [0.6, 0.8]
Application-Specific Recommendations:
- Weak Grid / Rural (Single-Phase):
- Industrial with PQ Standards:
- Critical Process / HVAC:
6. Emerging Trends & PQ Implications
7. Motor Testing & Efficiency Verification (IEC 60034-2-1)
PerIEC 60034-2-1, efficiency testing follows this sequence:
| Passo | Test Description | Purpose |
|---|---|---|
| 1 | Stator winding resistance at ambient temperature | Baseline measurement |
| 2 | Remove drive end sealing elements | Access for testing |
| 3 | 6.4.4.1 Rated load temperature test | Thermal performance |
| 4 | Second stator resistance measurement | Post-load resistance |
| 5 | 6.4.4.2/6.4.5.3 Load curve with torque measurement | Performance mapping |
| 6 | Third stator resistance measurement | Final resistance |
| 7 | 6.4.2 No-load test | Core losses |
| 8 | Fourth stator resistance measurement | No-load resistance |
| 9 | 8.2.2.3 Constant losses determination | Friction, windage, iron |
| 10 | 8.2.2.4 Load losses | Stator/rotor copper |
| 11 | 8.2.2.5 Additional load losses | Stray load losses |
| 12 | 8.2.2.2 Calculate total losses | Summation |
| 13 | 8.2.2.1 Calculate efficiency | Final result |
8. Standards Reference Table forIPQDF.com
9. IPQDF Discussion Topics with IEC Context
- Estudo de Caso: IEC 61000-4-30 Class A measurement of Written-Pole vs. Induction motor starting
- Standards Update: IEC 60034-30-1:2025 – What IE5 means for motor selection
- Measurement Challenge: Supraharmonics (2-150 kHz) perIEC 61000-4-30 Annex D from SiC VFDs
- Field Report: Retrofit of Rosenberg motors to modern IE3 designs
- Research Opportunity: Motor starting in weak grids – aligningIEC 60034-12 comIEC 61000-4-30 event detection
- Compliance Guide: MeetingIEC 60038 voltage requirements for international projects
10. Resources & Referências
Official IEC Standards (Purchase Required)
- IEC 60034-30-1:2025 – Efficiency classes (IE1-IE5)
- IEC 61000-4-30:2025 – PQ measurement methods
- IEC 60038:2009+AMD1:2021 – Standard voltages
- IEC 60034-12:2024 – Starting performance
- IEC 60034-2-1 – Efficiency test methods
- IEC 61800-1:2021 – DC power drive systems
Complementary IEEE Standards
- IEEE 519-2022 – Harmonic control in power systems
- IEEE 3002.7 – Motor starting considerations
- IEEE 115 – Synchronous machine testing
Industry References
- NEMA MG-1 – Motors and Generators (aligned with IEC 60034 série)
- EPRI Power Quality Manual – Motor starting guidelines
About IPQDF: The International Power Quality Discussion Forum brings together utility engineers, facility managers, consultants, and researchers to address global power quality challenges. Share your motor-related PQ experiences atwww.ipqdf.com.
*Document Version: 2.1 • Last Updated: Abril 2024 • IEC References: 2024-2025 Editions • Contributors: IPQDF Technical Committee*