Draft Inducer ECM Torque Range Control for Multistage Furnaces
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Solution Overview
Problem
Existing non-condensing furnace draft inducers lack efficient torque and rotational speed control, leading to suboptimal operation and potential inefficiencies during normal operation.
Innovation Solution
A permanent magnet electrically commutated motor with a controller that selectively operates in specific torque and rotational speed ranges, ensuring the motor operates within defined parameters during normal operation and transitions between states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor operates without restricted torque ranges, then the motor has greater operational flexibility, but the motor may operate in suboptimal conditions leading to inefficiency and potential damage
Solution Approach 1:
The controller dynamically adjusts the motor's operational parameters by implementing restricted torque ranges that change based on operating conditions. The controller monitors motor operation and enforces different torque limits during various operational states, allowing the system to adapt between reliability-focused and flexibility-focused modes as needed.
Solution Approach 2:
The system changes the torque parameter restrictions based on operational context. The controller implements specific torque ranges (first and second torque ranges) that are enforced during different operating conditions, transforming the motor's operational characteristics to prioritize reliability when needed while maintaining flexibility when conditions permit.
2Productivity
If the motor operates at variable speeds continuously, then the motor can adapt to varying load conditions, but the motor may experience wear and inefficiency during transitional states
Solution Approach 1:
The controller implements periodic operation between two distinct rotational speed ranges rather than allowing continuous variable operation. The motor alternates between a first rotational speed range and a second rotational speed range, with controlled transitions between them, reducing time spent in inefficient intermediate states while maintaining adaptability to load conditions.
Solution Approach 2:
The system dynamically switches between discrete speed ranges based on operational needs. The controller monitors load conditions and transitions the motor between the first and second rotational speed ranges, optimizing productivity while minimizing energy waste during transitions by making deliberate, controlled speed changes rather than continuous adjustment.
3Use of energy by moving object
If the motor operates in discrete torque ranges with gaps, then the motor operates more efficiently in defined states, but the motor loses continuous control capability
Solution Approach 1:
The controller changes the torque parameter enforcement based on operational mode. During normal operation, the controller enforces discrete torque ranges (first torque range and second torque range) to optimize energy efficiency. During transitionary periods, the controller temporarily allows operation between these ranges to maintain ease of operation and enable smooth state changes.
Solution Approach 2:
The system periodically alternates between enforced torque ranges and transitionary periods. The controller implements a rhythm of operation where the motor spends most time in efficient discrete torque ranges, with brief controlled transitions allowing operation in intermediate states when needed for state changes or load adjustments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances operational efficiency and prevents destructive condensate formation by maintaining precise torque and speed control, improving furnace performance and reliability.
Implementation Method 1
a permanent magnet electrically commutated motor... The motor comprises a stator, a rotor... The rotor is rotatable relative to the stator
Implementation Method 2
The motor cooling fan is configured and positioned to move air in a manner to cool at least some components of the motor
Data Source
AI summary
A furnace assembly comprising a non-condensing furnace with a draft inducer. The draft inducer includes a permanent magnet electrically commutated motor and a draft inducer blower fan. The motor includes a stator, a rotor, a motor cooling fan, and a controller. The rotor being rotatable relative to the stator, the fan being operatively coupled to the rotor such that rotation of the rotor causes rotation of the fan, the controller being configured to selectively operate the motor in first and second different torque ranges of the rotor, with the first and second torque range operating within a fixed percentage and within a fixed percentage of each other. The controller being configured such during normal operation, the motor is not operable at any torques between the first torque range and the second torque range except during transitionary periods.