Motor assembly with integrated on/off detection with speed profile operation
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Solution Overview
Problem
Refrigeration system motor assemblies face challenges in determining the operational state of a compressor motor, which affects the control of fan motors, as simple voltage measurements are unreliable due to induced voltage responses when the compressor is disconnected from the line voltage.
Innovation Solution
A motor assembly with a state detection circuit that evaluates the external alternating voltage relative to line and neutral connections, using logic output signals to determine the compressor's operational state and control the motor's speed profiles accordingly, allowing for efficient energy management and maintenance operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If simple voltage measurements are used to detect compressor operational state, then the detection method is simple, but the measurement precision is poor due to induced voltage responses
Solution Approach 1:
The voltage detection is segmented into multiple components: the state detector separately measures line-to-neutral voltage, line-to-line voltage, and neutral-to-neutral voltage. By dividing the detection into distinct voltage component measurements, the system achieves accurate compressor state detection while maintaining measurement simplicity.
Solution Approach 2:
The patent introduces an intermediary measurement approach by detecting voltage relative to both line and neutral connections. The state detector uses neutral connection as an intermediary reference point to distinguish between compressor on/off states, eliminating the interference of induced voltage responses.
2Ease of operation
If the motor runs continuously regardless of compressor state, then operation is simple, but energy consumption increases
Solution Approach 1:
The control unit receives feedback signals from the state detector about the compressor's operational state. Based on this feedback, the control unit automatically adjusts the motor's speed profile - running at higher speed when compressor is off and reducing speed when compressor is on, thereby reducing energy consumption while maintaining simple operation through automatic control.
Solution Approach 2:
The motor operates with dynamic speed profiles that change based on compressor state. The control unit adjusts motor speed dynamically - using higher speeds during compressor off periods for maintenance functions like air circulation and condenser cleaning, and lower speeds during compressor operation, optimizing energy usage throughout the system cycle.
3Loss of energy
If the motor speed is reduced when compressor is on, then energy savings are achieved, but maintenance functions like air circulation are compromised
Solution Approach 1:
The motor operates with periodic speed variations synchronized to the compressor cycle. During compressor off periods, the motor runs at higher speed to perform maintenance functions like air circulation and condenser coil cleaning. When the compressor turns on, the motor reduces speed. This periodic action ensures both energy savings and effective maintenance functions are achieved at appropriate times.
Data Source
AI summary
A motor assembly configured to receive an external alternating voltage. The motor assembly includes a motor and a circuit assembly. The motor includes a stator and a rotor rotatable about a longitudinal axis. The circuit assembly includes a state detector and a control unit. The state detector is operable to detect whether an external device is receiving the external alternating voltage The control unit is operable to control the motor based on whether the external device is receiving the external alternating voltage.