I. Project Background and Key Challenges
1. Current Site Equipment Status
Original Motor: Inner-fed speed control three-phase asynchronous motor, Model YQT630-6G, 900kW, 10kV, commissioned in 2016.
Associated Pump: Wilo centrifugal pump, Model SCPG20/24DV MED1-900/6.
Years in Service: Both the motor and pump have been in continuous operation since 2016.
2. Procurement Objective
To procure one spare inner-fed speed control motor capable of directly replacing the existing motor when required, driving the existing Wilo pump, and maintaining full compatibility with the existing inner-fed speed control system.
3. Risk of Service Life Discrepancy
The existing pump has been in service for nearly ten years. Hidden wear or deformation may have developed in the coupling and foundation over this period. Even though the new motor will be manufactured to theoretical dimensional specifications, shaft alignment deviations may still arise upon installation.
Accordingly, site surveying must not be treated as a simple nameplate verification exercise. It is an essential in-depth compatibility assessment and risk evaluation that must be carried out with full rigor.
II. Site Survey and Interface Investigation Plan
Prior to executing the technical agreement, the motor supplier must be arranged to conduct an on-site dimensional survey of the installed motor and produce formal documentation of all findings. The installation dimensions of the new motor must fully conform to the existing foundation conditions and allow complete like-for-like replacement of the current motor. Electrical connection locations and configurations must, to the greatest extent practicable, match those of the existing motor, so that replacement does not introduce any issues with power cabling or control circuit connections.
2.1 Foundation and Motor Installation Dimensional Survey
The following must be measured on-site:
Actual dimensions of the motor mounting foundation, including peripheral boundary dimensions, hold-down bolt positions, and the distance from the foundation to the pump end.
Actual installed dimensions of the existing motor.
The objective is to ensure that the new motor fits the existing foundation precisely, with no unsupported overhangs or physical obstructions after installation.
Note: The existing motor is a wound-rotor type with an IC611 cooling arrangement. The shaft extension end has a relatively long "C" dimension, and the motor mounting space is compact. On-site measurements must be taken with the highest possible accuracy to provide a reliable basis for subsequent manufacturing and installation.
2.2 Electrical Interface and Control System In-Depth Investigation
Main Terminal Box Position Survey
The motor is fitted with multiple terminal boxes. The spatial position of each box — including its fore-and-aft location and height — must be carefully recorded, along with the terminal hole diameters inside each box. This is essential to ensure that all cable connections remain accessible and feasible once the new motor is installed in position.
Auxiliary Equipment Interface Verification
The following auxiliary devices must be checked for model compatibility and wiring configuration to ensure full instrument system compatibility:
Temperature sensors (PT100 RTDs)
Anti-condensation heaters
Vibration sensors
All interface types, connector specifications, and wiring arrangements must be verified against the existing installation and confirmed compatible before the new motor is manufactured.
