Efficient solution for draft machines: EF high-voltage electric motors in action

Project / Customer

Project: An effective solution for draft machines: development, production and supply of high-voltage electric motors of our own brand “EF” for new CHP units.
Customer: Large Russian energy generating company
Equipment: Draft installations (smoke exhausters and fans)
Product: Asynchronous high-voltage electric motors of our own brand "EF"
Geography of production: China (own certified site)

Introduction

As part of the construction of new CHP units, the customer needed to select electric motors for draft machines (TDM) types VDN-31.5K-0.95, DN-32x2-0.62K-0.97 and DRG-32-100.

EnergoFront engineers were faced with a complex task: in a short time, to develop and supply a batch of asynchronous electric motors with a power of 1250 kW, 2000 kW and 1600 kW, ensuring their reliable direct start and operation in extreme climatic conditions.

Main difficulties at the start:

• Equipment heterogeneity: 3 non-standard machine sizes with different aerodynamic and torque curves.
• Strict requirements for direct starting: from a cold state - 2 starts in a row, from a hot state - 1 start.
• Extreme climatic version: outside air temperature range from -60°C to +40°C.
• Short delivery times.

Objective and technical requirements

Develop, manufacture and supply a batch of asynchronous electric motors with the following parameters:

Key Engineering Challenge: calculate and design electric motors with specified starting characteristics, taking into account direct start and operation in conditions of low outdoor temperatures, ensuring the start of the TDM in the required time, in order to avoid overheating.

Custom engineering solutions

1. Aerodynamic analysis

EnergoFront engineers requested the characteristics of draft machines and recalculated the given aerodynamic curves (the dependence of the mechanism resistance on performance). Based on these data, the characteristics of the motors (the shape of the electromagnetic torque) were adjusted, which made it possible to eliminate “failures” when reaching the operating mode.

2. Engineering and design adaptation

Motors have been designed with the following technical features:

• Aluminum rotor – to ensure the required starting properties for electric motors of 1250 and 2000 kW.
• Class F reinforced insulation with a heating margin up to class H - for reliability during operation in conditions of UHL3, -60°C...+40°C.
• Housing protection IP54 – protection from dust and moisture, which is inevitable in the area of draft installations.

Taking into account the moments of inertia of the rotor of the mechanism:

• For 1250 kW motor – J = 3900 kg/m²
• For 2000 kW ED – J = 8000 kg/m²
• For 1600 kW ED – J = 3500 kg/m²

3. On-site production in China

Production was launched at a certified site in China. Why this was an advantage:

• Optimized purchasing electrical steel and copper (cost reduction without loss of quality).
• Availability of a test bench with a power of up to 5 MW – allowed for 4-hour testing under rated load.

Testing and quality control

All electric motors have passed a full cycle of factory tests according to the GOST methodology (analogous to IEC):

1. Insulation resistance measurement (2500 V megger).
2. High Voltage Test (Usp = 2Unom + 1000 V) for 1 minute.
3. Removing Load Characteristics (operation under rated load with measurements of current, active power, temperature of windings and bearings).
4. Vibroacoustic diagnostics – the vibration level did not exceed 2.8 mm/s (class A according to GOST ISO 10816-3).

Test result: Actual deviations in no-load current and efficiency did not exceed the rated values (+0.5%). The engines successfully worked for 2 hours at forced mode (10% overload). Locked rotor tests: 5.54 In, 1.62 Tn.

Sales at the customer's site

Delivery of electric motors with a set of accompanying documentation (Drawings, operation manuals, Passports, test reports, quality certificates, installation instructions) was completed within a strictly specified time frame.

Summary of results achieved

Conclusion

The project to supply high-voltage electric motors "EF" confirmed the ability of the EnergoFront team to solve complex engineering problems at the intersection of aerodynamics, electromagnetic design and adaptation to extreme climatic conditions.

Successful direct launch of various draft machines, ensuring high efficiency and significant savings in the customer’s budget (reduction of contract costs by 48%) demonstrate the company’s systematic approach:

• Deep technical expertise - aerodynamic analysis and accurate calculation of the electromagnetic torque to eliminate “failures” during startup.
• Adaptation to extreme conditions - use of reinforced insulation and special design solutions for operation at -60°C.
• Production optimization - use of a certified site in China to reduce costs without loss of quality.
• Multi-level quality control - full cycle of tests according to GOST, including 4-hour loads and vibroacoustic diagnostics.

The implemented project ensured the reliable launch of new CHP units and contributed to increasing the energy efficiency of Russian generation.