Condenser Motor Load for HVAC Compressor Backspin Inhibition

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In HVAC systems, compressor motors can backspin due to high refrigerant pressure, generating excessive voltage that can damage electrical components, and existing solutions like mufflers and chopper resistors are not always effective in preventing damage.

Innovation Solution

The condenser motor is electrically coupled to the compressor assembly to dissipate the electric power generated during backspinning, using it as an electric load to inhibit reverse rotation and prevent voltage spikes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If permanent magnet compressor motors are used to compress refrigerant, then compression efficiency is improved, but the motors become susceptible to backspinning which generates excessive voltage that can damage electrical components

Engineering Contradiction:

Improvecompression efficiencyVSAvoidvoltage damage to electrical components

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful backspin energy into a beneficial braking force. When the compressor motor backspins due to high refrigerant pressure, the condenser motor (operating as a generator) converts this reverse rotation into electrical energy that creates a counter-torque, effectively using the harmful backspin motion to create a braking force that prevents damage to electrical components.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The condenser motor serves as an intermediary between the backspinning compressor motor and the electrical system. Instead of allowing the backspin energy to directly damage electrical components, the condenser motor intercepts this energy, converts it to electrical power, and dissipates it through the electrical load, thereby protecting the system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If mufflers and check valves are used to inhibit reverse refrigerant gas flow and backspin, then backspin is reduced, but device complexity and component count increase

Engineering Contradiction:

Improvebackspin inhibitionVSAvoidcomponent count

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The condenser motor performs multiple functions: it drives the condenser fan during normal operation and simultaneously serves as an electrical load and brake during compressor backspin events. This multi-functionality eliminates the need for separate mufflers and check valves, reducing component count while maintaining backspin inhibition capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of the condenser motor with the backspin inhibition system. Instead of having separate components for fan drive and backspin protection, the condenser motor is integrated to perform both roles, thereby simplifying the overall system architecture.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If chopper resistors are used to produce braking torque and inhibit backspinning, then backspin is prevented, but device complexity and additional components are required

Engineering Contradiction:

Improvebackspin preventionVSAvoidcomponent count

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The condenser motor is self-sufficient in providing braking torque during backspin events. It generates its own electrical load and braking force through its normal operation as a motor-generator, eliminating the need for external chopper resistors or additional braking components.

Inventive Principle:

Principle #25Self-service

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

This solution effectively prevents damage to electrical components by safely dissipating the generated power, eliminating the need for additional components like chopper resistors and mufflers, thereby enhancing the reliability of HVAC systems.

Implementation Method 1

the compressor motor may cease operating. If the compressor is, e.g, a scroll or screw compressor, the high pressure of the refrigerant may force the compressor motor to rotate in reverse, sometimes referred to as backspinning. Many compressors employ permanent magnet compressor motors (i.e., motors having surface and/or embedded permanent magnets). A backspinning permanent magnet motor becomes a generator.

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

using the condenser motor as an electric load to dissipate electric power generated by the compressor motor when the compressor motor backspins

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS8855474B2Inhibiting compressor backspin via a condenser motor

Publication Date: 2014.10.07 COPELAND LP

AI summary

Assemblies for HVAC systems and methods of operating HVAC systems are disclosed, including a method of operating an HVAC system having a compressor assembly and a condenser assembly. The compressor assembly includes a compressor having a compressor motor that is susceptible to backspinning and capable of generating electric power when backspinning. The condenser assembly includes a condenser motor operatively coupled to a fan. The condenser assembly is electrically coupled to the compressor assembly. The method includes using the condenser motor as an electric load to dissipate electric power generated by the compressor motor when the compressor motor backspins.