American Standard Inc.

Trane International Inc.

American Standard International Inc.

Robert M Swanson

Michael G Lunacek

David Marshall Foye

Dennis R Dorman

Paul C Rentmeester

Jeffrey A Moore

Lunxi Peter Xia

Rolf M Hanson

Nels R Ebbesen

Joel C VanderZee

Robert E Krocker

Merle A Renaud

Terence D Baier

Joel S Duga

Patrick J Wilson

Kirk W Johnson

Paul C Pentmeester

To protect the bearings, lubricant and seals of a refrigerant compressor, the compressor includes one or more inductors for mitigating a high frequency common mode current that produces a high frequency shaft voltage. Each inductor is a ring of magnetic material encircling three insulated cables that convey three-phase power from an adjustable frequency drive to the compressor's motor. Without the inductors, the high frequency shaft voltage can become damagingly high due to the length of a cast iron housing that can be particularly long if the housing contains both a motor and several centrifugal impellers. The high frequency shaft voltage is just one component of a composite adverse shaft voltage. Another component, known as an operationally induced shaft voltage, can be reduced by a grounding contact, so instead of using just an inductor or just a contact, both can be used to provide a total solution to the problem.

System for protecting bearings and seals of a refrigerant compressor

A system for servicing a computer controlled machine comprising: a computer controlled machine including a device operable to perform a function, a controller controlling the operation of that device, and a data access port for transferring data and commands from the controller; and a service tool operably connected to the data access port, the service tool including a remote communications capability, a computer, and diagnostics and graphing software; and an expert observer system operably linked to the remote communications capability of the service tool and including historical machine data, machine sales information, software revisions for the controller, additional diagnostics software, and an expert observer capable of providing a mentor capability to the operator of a service tool.

HVAC service tool with internet capability

A communications protocol for a communications bus wherein messages are transmitted to a plurality of devices communicating by a bus. Each message includes a unique code indicating the end of the message and that same unique code triggers a transfer of communications control to another device of the plurality of devices.

Multiple device communications

A method of measurement. The method comprises the steps of (a) measuring a value, (b) forwarding the measured value as an analog signal, (c) dithering the analog signal to improve resolution and (d) converting the analog signal to a digital signal.

Dithering an analog signal to improve measurement

A device for monitoring and modulating the admission of fresh air into a building. The device comprises a housing; a sensor associated with the housing and operable to measure airflow through the housing; and a damper including at least two damper blades. Each damper blade includes a shaft rotatably attached to the housing at least at a first shaft end. The shaft is located on the surface of the damper blade so as to divide the surface into first and second substantially equal areas.

Fresh air flor modulation device

Fresh air flow modulation device

A method of protecting the compressor motor of a refrigeration system using a multiphase AC power source. The method comprises the steps of monitoring each phase of the power supply to the compressor motor; calculating the average phase for the phases of the AC power supply; determining a maximum phase unbalance deviation from the average phase; determining if a first level of phase unbalance protection is active; setting a system protection level as the first level of phase unbalance protection if the first level is active; setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and initiating a compressor motor shutdown if the system protection level is exceeded by the maximum unbalanced phase deviation.

Multilevel phase unbalance compressor motor protection system

A method, and apparatus, for protecting a compressor motor in a refrigeration system from overload comprising the steps of setting a first overload trip point; setting a second overload trip point; comparing the first trip point setting with the second trip point setting; and shutting down the compressor motor if the first trip point setting is not substantially equal to the second trip point setting.

Compressor motor protection system

Growing community of inventors

La Crosse, WI, United States of America

Robert M Swanson