Abstract: A control system is provided that can identify the occurrence of a single surge cycle in centrifugal compressor using various methods and devices. Once the occurrence of a single surge cycle is identified, the control system can take remedial action to respond to the surge cycle, such as by adjusting the position of a variable geometry diffuser, and restore the centrifugal compressor to stable operation.

Abstract: An improved variable geometry diffuser (VGD) mechanism for use with a centrifugal compressor. This VGD mechanism extends substantially completely into the diffuser gap so that the VGD mechanism may be used more fully to control other operational functions. The VGD mechanism may be used to minimize compressor backspin and associated transient loads during compressor shut down by preventing a reverse flow of refrigerant gas through the diffuser gap during compressor shutdown, which is prevented because the diffuser gap is substantially blocked by the full extension of the diffuser ring. During start-up, transient surge and stall also can be effectively eliminated as gas flow through the diffuser gap can be impeded as load and impeller speed increase, thereby alleviating the problems caused by startup loads at low speeds. The VGD mechanism can be used for capacity control as well so as to achieve more effective turndown at low loads.

Abstract: An improved variable geometry diffuser (VGD) mechanism for use with a centrifugal compressor. This VGD mechanism extends substantially completely into the diffuser gap so that the VGD mechanism may be used more fully to control other operational functions. The VGD mechanism may be used to minimize compressor backspin and associated transient loads during compressor shut down by preventing a reverse flow of refrigerant gas through the diffuser gap during compressor shutdown, which is prevented because the diffuser gap is substantially blocked by the full extension of the diffuser ring. During start-up, transient surge and stall also can be effectively eliminated as gas flow through the diffuser gap can be impeded as load and impeller speed increase, thereby alleviating the problems caused by startup loads at low speeds. The VGD mechanism can be used for capacity control as well so as to achieve more effective turndown at low loads.

Abstract: An improved variable geometry diffuser (VGD) mechanism for use with a centrifugal compressor. This VGD mechanism extends substantially completely into the diffuser gap so that the VGD mechanism may be used more fully to control other operational functions. The VGD mechanism may be used to minimize compressor backspin and associated transient loads during compressor shut down by preventing a reverse flow of refrigerant gas through the diffuser gap during compressor shutdown, which is prevented because the diffuser gap is substantially blocked by the full extension of the diffuser ring. During start-up, transient surge and stall also can be effectively eliminated as gas flow through the diffuser gap can be impeded as load and impeller speed increase, thereby alleviating the problems caused by startup loads at low speeds. The VGD mechanism can be used for capacity control as well so as to achieve more effective turndown at low loads.

Abstract: An improved variable geometry diffuser (VGD) mechanism for use with a centrifugal compressor. This VGD mechanism extends substantially completely into the diffuser gap so that the VGD mechanism may be used more fully to control other operational functions. The VGD mechanism may be used to minimize compressor backspin and associated transient loads during compressor shut down by preventing a reverse flow of refrigerant gas through the diffuser gap during compressor shutdown, which is prevented because the diffuser gap is substantially blocked by the full extension of the diffuser ring. During start-up, transient surge and stall also can be effectively eliminated as gas flow through the diffuser gap can be impeded as load and impeller speed increase, thereby alleviating the problems caused by startup loads at low speeds. The VGD mechanism can be used for capacity control as well so as to achieve more effective turndown at low loads.

Abstract: A method for cooling a compressor motor (170) and a cooling circuit utilizing refrigerant that originates in the condenser (30) to cool a motor (170) and electromagnetic bearings (196, 206). The motor drives a compressor (20), while the electromagnetic bearings support the motor rotor (178) during operation of the compressor. Liquid refrigerant from the condenser is expanded into a two-phase mixture, passed over the stator, expanded a second time, passed over the bearings and between the stator and rotor, before being returned to an evaporator (50).

Abstract: A method for cooling a compressor motor (170) and a cooling circuit utilizing refrigerant that originates in the condenser (30) to cool a motor (170) and electromagnetic bearings (196, 206). The motor drives a compressor (20), while the electromagnetic bearings support the motor rotor (178) during operation of the compressor. Liquid refrigerant from the condenser is expanded into a two-phase mixture, passed over the stator, expanded a second time, passed over the bearings and between the stator and rotor, before being returned to an evaporator (50).

Abstract: An improved variable geometry diffuser (VGD) mechanism for use with a centrifugal compressor. This VGD mechanism extends substantially completely into the diffuser gap so that the VGD mechanism may be used more fully to control other operational functions. The VGD mechanism may be used to minimize compressor backspin and associated transient loads during compressor shut down by preventing a reverse flow of refrigerant gas through the diffuser gap during compressor shutdown, which is prevented because the diffuser gap is substantially blocked by the full extension of the diffuser ring. During start-up, transient surge and stall also can be effectively eliminated as gas flow through the diffuser gap can be impeded as load and impeller speed increase, thereby alleviating the problems caused by startup loads at low speeds. The VGD mechanism can be used for capacity control as well so as to achieve more effective turndown at low loads.

Abstract: A cooling system for a motor powering a compressor in a vapor compression system includes a housing and a cavity within the housing. A first fluid circuit has a first connection to receive a refrigerant into the cavity, and a second connection to deliver refrigerant from the cavity to a heat exchanger for a heat transfer relationship with a heat-generating component.

Abstract: A cooling system for a motor powering a compressor in a vapor compression system includes a housing enclosing the motor and a cavity located within the housing. A fluid circuit circulates a cooling fluid in the motor, and includes a first connection in the housing to receive cooling fluid and a second connection in the housing to remove cooling fluid. The fluid circuit includes a passageway for cooling fluid positioned in an internal chamber formed in a motor shaft.

Abstract: A motor coolant method and system is used to cool a compressor motor (36) in a refrigeration system having a multi-stage compressor (38). The compressor includes a first compressor stage (42) and a second compressor stage (44), the first compressor stage providing compressed refrigerant to an input of the second compressor stage. The motor coolant system has a first connection with the refrigerant loop to receive refrigerant into the motor cavity for cooling, the received refrigerant provided from a system component having a high pressure, and a second connection with the refrigerant loop to return refrigerant to an intermediate pressure greater than an evaporator operating pressure. The pressure inside the motor cavity may be approximately the pressure within the first stage discharge and second stage suction to minimized seal leakage between the motor cavity and the internal pressures of the first and second stage compressors.

Abstract: A control system is provided that can identify the occurrence of a single surge cycle in centrifugal compressor using various methods and devices. Once the occurrence of a single surge cycle is identified, the control system can take remedial action to respond to the surge cycle, such as by adjusting the position of a variable geometry diffuser, and restore the centrifugal compressor to stable operation.

Abstract: A motor coolant method and system is used to cool a compressor motor (36) in a refrigeration system having a multi-stage compressor (38). The compressor includes a first compressor stage (42) and a second compressor stage (44), the first compressor stage providing compressed refrigerant to an input of the second compressor stage. The motor coolant system has a first connection with the refrigerant loop to receive refrigerant into the motor cavity for cooling, the received refrigerant provided from a system component having a high pressure, and a second connection with the refrigerant loop to return refrigerant to an intermediate pressure greater than an evaporator operating pressure. The pressure inside the motor cavity may be approximately the pressure within the first stage discharge and second stage suction to minimized seal leakage between the motor cavity and the internal pressures of the first and second stage compressors.

Abstract: A cooling system is provided for a motor powering a compressor in a vapor compression system. The cooling system including a housing and a cavity within the housing. A first fluid circuit has a first connection to receive a refrigerant into the cavity, and a second connection to deliver refrigerant from the cavity to a heat exchanger for a heat transfer relationship with a heat-generating component.

Abstract: A cooling system is provided for a motor powering a compressor in a vapor compression system. The cooling system includes a housing enclosing the motor, and a cavity located within the housing. A fluid circuit circulates a cooling fluid in the motor, the fluid circuit having a first connection in the housing to receive cooling fluid, and a second connection in the housing to remove cooling fluid in fluid communication with the loop. The fluid circuit includes a passageway for cooling fluid positioned in an internal chamber formed in a motor shaft.