Transport Refrigeration Auxiliary Power Interlock for Fast Equipment Swaps
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Solution Overview
Problem
Conventional transport refrigeration units require time-consuming and labor-intensive field wiring for installing and removing auxiliary power circuits to support optional systems, which increases pre-trip and post-trip installation and removal time.
Innovation Solution
A built-in auxiliary power circuit within the transport refrigeration unit that energizes only when the evaporator fan motors are active, with a safety interlock that disconnects power when the auxiliary system is removed, and a seal cap to ensure safe and efficient power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If field wiring is used to provide auxiliary power circuit, then auxiliary system can be powered, but installation and removal time increases
Solution Approach 1:
The auxiliary power circuit is pre-wired and built into the refrigeration unit during manufacturing, with power outlets and interlock circuits already in place. This preliminary preparation eliminates the need for time-consuming field wiring during installation, as the auxiliary system can be connected by simply plugging into the pre-configured outlets.
Solution Approach 2:
The built-in auxiliary power circuit serves multiple functions: it can power various types of auxiliary systems (ozone generators, heating elements, etc.), accommodate different container configurations, and work with both temporary and permanent auxiliary equipment through standardized power outlets.
2Adaptability or versatility
If auxiliary system is removed to de-customize container, then container versatility is improved, but power circuit removal labor increases
Solution Approach 1:
The auxiliary power system is segmented into modular components: the built-in power outlets, the removable auxiliary system, and the seal cap. This segmentation allows the auxiliary system to be easily disconnected and removed without affecting the permanent refrigeration unit, reducing labor for both installation and removal operations.
Solution Approach 2:
The seal cap serves as a temporary protective element that is easily installed and removed. When the auxiliary system is not in use, the seal cap simply covers the power outlet, providing a low-cost, easy-to-deploy solution for maintaining container versatility without requiring complex disconnection procedures.
3Ease of operation
If auxiliary power circuit is always energized, then power availability is improved, but safety risk increases
Solution Approach 1:
The interlock circuit continuously monitors the presence and proper installation of the auxiliary system. When the auxiliary system is correctly connected, the circuit receives feedback that power can be supplied. When the auxiliary system is removed or improperly connected, the interlock detects this condition and automatically interrupts power supply, preventing electrical hazards.
Solution Approach 2:
The interlock circuit acts as an intermediary between the power source and the auxiliary system. It controls the flow of electricity by enabling or disabling power supply based on the auxiliary system's installation status, serving as a safety mediator that prevents direct exposure to electrical hazards while maintaining power availability when needed.
Data Source
AI summary
A pre-wired auxiliary power circuit (45, 47) is built into a transport refrigeration system for supplying electrical power to an optional auxiliary system when installed in connection with the transport refrigeration unit. A low cost safety interlock (70) is provided in association with the auxiliary power circuit.