Active bearing temperature control

Abstract

A method of active bearing temperature control.SOLUTION: An electric motor assembly includes a shaft, a bearing, at least one fluid channel, a temperature sensor, a lubricant supply pump, a controller, and a bearing interface. The at least one fluid channel is fluidly coupled with the bearing interface. The temperature sensor detects a temperature of the bearing. The lubricant supply pump transports lubricant from the lubricant supply to the bearing interface via the at least one fluid channel. The controller receives the temperature of the bearing from the temperature sensor, determines a difference between the temperature of the bearing and the lubricant supply temperature, determines a lubricant flow rate based on the difference, and sends a control signal to the lubricant supply pump to cause the lubricant supply pump to transport lubricant to the bearing interface at the lubricant flow rate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims the benefit of and priority to U.S. Provisional Patent Application No. 62 / 712,292, entitled "ACTIVE BEARING TEMPERATURE CONTROL," filed July 31, 2018, the disclosure of which is incorporated herein by reference in its entirety. [Background technology]

[0002] A building may include a heating, ventilation, and air conditioning (HVAC) system. The HVAC system may include an electric motor that drives a compressor, such as the compressor in a chiller assembly. An oil pump may be used to lubricate the electric motor. Summary of the Invention [Means for solving the problem]

[0003] One implementation of the present disclosure is an electric motor assembly. The electric motor assembly includes a shaft, a bearing, at least one fluid channel, a temperature sensor, a lubricant supply pump, and a controller. The bearing defines a bearing interface, and the shaft rotates relative to the bearing interface. The at least one fluid channel is fluidly coupled to the bearing interface. The temperature sensor detects a temperature of the bearing. The lubricant supply pump is fluidly coupled to the at least one fluid channel to deliver lubricant from a lubricant supply source to the bearing interface via the at least one fluid channel. The controller receives the temperature of the bearing from the temperature sensor, determines a difference between the temperature of the bearing and a supply temperature of the lubricant, determines a lubricant flow rate based on the difference, and sends a control signal to the lubricant supply pump to deliver lubricant to the bearing interface at the lubricant flow rate.

[0004] Another implementation of the present disclosure is a method for active bearing temperature control that includes: detecting, by a temperature sensor, a temperature of a bearing, the bearing defining a bearing interface and a shaft rotating relative to the bearing interface; receiving, by a controller, the temperature of the bearing from the temperature sensor; determining, by the controller, a difference between the temperature of the bearing and a supply temperature of lubricant from a lubricant supply source, the lubricant supply source fluidly coupled to a lubricant supply pump and at least one fluid channel fluidly coupled to the bearing interface; determining, by the controller, a lubricant flow rate based on the difference; and sending, by the controller, a control signal to the lubricant supply pump to cause the lubricant supply pump to transport lubricant from the lubricant supply source to the bearing interface at the lubricant flow rate.

[0005] Another implementation of the present disclosure is a controller. The controller includes one or more processors and a memory device containing non-transitory machine-readable instructions. When executed, the instructions cause the one or more processors to: receive a temperature of a bearing from a temperature sensor, the bearing defining a bearing interface relative to which a shaft rotates; determine a difference between the temperature of the bearing and a supply temperature of lubricant from a lubricant supply source, the lubricant supply source being fluidly coupled to a lubricant supply pump and having at least one fluid channel fluidly coupled to the bearing interface; determine a lubricant flow rate based on the difference; and send a control signal to the lubricant supply pump to cause the lubricant supply pump to transport lubricant from the lubricant supply source to the bearing interface at the lubricant flow rate.

[0006] Those skilled in the art will appreciate that this summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features and advantages of the devices and / or processes described herein, as defined solely by the claims, will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 illustrates a chiller assembly according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram of the electric motor of the chiller assembly of FIG. 1. [Figure 3] FIG. 1 is a block diagram of an electric motor assembly that may implement active bearing temperature control according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view of the electric motor assembly of FIG. 3. [Figure 5] 1 is a flow diagram of a method for active temperature bearing control according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present disclosure relates generally to HVAC systems, and more particularly to active bearing temperature control, such as active bearing temperature control in bearings of electric motors. Referring generally to the figures, an electric motor assembly capable of driving a compressor is shown. The electric motor assembly may include a shaft, a bearing, at least one fluid channel, a temperature sensor, a lubricant supply pump, and a controller. The bearing defines a bearing interface relative to which the shaft rotates. The at least one fluid channel is fluidly coupled to the bearing interface. The temperature sensor detects the temperature of the bearing. The lubricant supply pump is fluidly coupled to the at least one fluid channel to transport lubricant from a lubricant supply source to the bearing interface via the at least one fluid channel. The controller receives the temperature of the bearing from the temperature sensor, determines a difference between the temperature of the bearing and a supply temperature of the lubricant, determines a lubricant flow rate based on the difference, and sends a control signal to the lubricant supply pump to cause the lubricant supply pump to transport lubricant to the bearing interface at the lubricant flow rate. By controlling the lubricant flow rate based on the difference between the bearing temperature and the supply temperature, the present solution can ensure that the bearing temperature does not rise above desired operating conditions while reducing or eliminating the possibility of lubricant leaking from the bearing interface into the housing of the electric motor assembly (compared to existing systems that supply oil to the bearing interface at a constant flow rate).

[0009] Chiller Assembly Referring to FIG. 1, a chiller assembly 100 is shown comprising a compressor 102 driven by an electric motor 104, a condenser 106, and an evaporator 108. A refrigerant is circulated in a vapor compression cycle through the chiller assembly 100. The chiller assembly 100 may also comprise a control panel 114 for controlling the operation of the vapor compression cycle within the chiller assembly 100. The control panel 114 may be connected to an electronic network for sharing various data related to maintenance, analysis, etc.

[0010] The electric motor 104 may be powered by a variable speed drive (VSD) 110. The VSD 110 receives alternating current (AC) power having a particular fixed line voltage and fixed line frequency from an AC power source (not shown) and supplies power having a variable voltage and frequency to the electric motor 104. The electric motor 104 may be any type of electric motor that may be powered by the VSD 110. For example, the electric motor 104 may be a high-speed induction motor. The compressor 102 is driven by the electric motor 104 to compress refrigerant vapor received from the evaporator 108 via a suction line 112. The compressor 102 then delivers the compressed refrigerant vapor to the evaporator 108 via a discharge line 112. The refrigerant is then passed to a condenser 106. The compressor 102 may be a centrifugal compressor, a screw compressor, a scroll compressor, a turbine compressor, or any other type of suitable compressor.

[0011] The refrigerant vapor delivered to the condenser 106 by the compressor 102 transfers heat to the fluid. The refrigerant vapor condenses into a refrigerant liquid in the condenser 106 as a result of the heat transfer with the fluid. The refrigerant liquid from the condenser 106 flows through an expansion device and back to the evaporator 108 to complete the refrigerant cycle of the chiller assembly 100. The condenser 106 includes a supply line 116 and a return line 118 for circulating a fluid between the condenser 106 and an external component of the HVAC system (e.g., a cooling tower). The fluid supplied to the condenser 106 via the return line 118 exchanges heat with the refrigerant in the condenser 106 and is removed from the condenser 106 via the supply line 116 to complete the cycle. The fluid circulating through the condenser 106 can be water or any other suitable fluid.

[0012] Referring now to FIG. 2 , the electric motor 104 is shown in more detail. The electric motor 104 may be a high-speed induction motor configured to directly drive the centrifugal compressor (i.e., compressor 102). The electric motor 104 is shown to include a shaft 212, a rotor 214, and a stator 216. The stator 216 is supplied with AC power (e.g., from the VSD 110) and includes windings capable of generating a magnetic field. The magnetic field can induce an electromagnetic force that produces a torque about the axis of the rotor 214. As a result, the rotor 214 and shaft 212 begin to rotate in a circular motion. The shaft 212 may be connected to an impeller 220 of the compressor 102 via a direct drive mechanism 218. The impeller 220 may therefore rotate at high speeds to increase the pressure of the refrigerant vapor within the compressor 102.

[0013] The electric motor 104 is shown with a first bearing 230 (e.g., a pressure dam bearing) located at the drive end of the electric motor 104 and a second bearing 240 (e.g., a pressure dam bearing) located at the non-drive end of the electric motor. The bearings 230 and 240 support the shaft 212 and may be lubricated with oil or another type of lubricant. When the electric motor 104 is energized and the shaft 212 begins to rotate, the shaft 212 can rotate against the backdrop of a thin film of lubricant coating the inside of the bearings 230 and 240.

[0014] Active bearing temperature control for HVAC motor bearings 3 and 4, an electric motor assembly 300 is shown that provides lubricant to the bearings of an electric motor. The electric motor assembly 300 may incorporate features of the chiller assembly 100; for example, the electric motor assembly 300 may comprise the electric motor 104 and may be used to provide lubricant to the bearings 230 (and / or bearings 240) of the electric motor 104 to facilitate rotation of the shaft 212 relative to the stator 216. The lubricant may include a fluid such as oil.

[0015] The electric motor assembly 300 includes a bearing 304. The bearing 304 may be used to implement one or both of the bearings 230, 240 described with reference to FIG. 2 . The bearing 304 is located between the shaft 212 and the stator 216. The bearing 304 defines a bearing interface 308 on an inner surface of the bearing 304. The shaft 212 may rotate relative to the bearing interface 308. For example, the shaft 212 may rotate on a film of lubricant on the bearing interface 308. As the shaft 212 rotates relative to the bearing interface 308, heat may be generated and transferred to the bearing 304 (and other components proximate the bearing interface 308). For example, friction between the shaft 212 and the bearing 304 may generate heat that is transferred to the bearing 304.

[0016] In some embodiments, as the speed of rotation of the shaft 212 increases (or decreases), friction The increase (or decrease) in raw velocity and therefore the temperature of the bearing increases (or decreases), such as due to heat transfer to the bearing 304 through the bearing interface 308 .

[0017] In some embodiments, the lubricant supply pump 312 transports lubricant from the lubricant supply source 316 to the bearing 304 (and bearing interface 308) via at least one fluid channel 320. The at least one fluid channel 320 is fluidly coupled to the bearing interface 308. The at least one fluid channel 320 can comprise a first channel 316a that receives lubricant from the lubricant supply source 316 and supplies it to the bearing 304, and a second channel 320b that receives lubricant from the bearing 304 and transports it away from the bearing 304; for example, as shown, the second channel 316b can transport lubricant from the bearing 304 to the lubricant supply source 316.

[0018] The lubricant supply pump 312 may include a variable speed pump. For example, the lubricant supply pump 312 may receive a control signal indicating a speed of operation of the lubricant supply pump 312 and adjust its operation to achieve the indicated speed, e.g., to deliver lubricant at a flow rate corresponding to the indicated speed.

[0019] By transporting lubricant to and from bearing interface 308, lubricant supply pump 312 can reduce the rate of friction-based heat generation between shaft 212 and bearing 304 by at least one of (1) reducing friction between shaft 212 and bearing interface 308 and (2) transporting heat away from the bearing interface due to the flow of lubricant away from bearing interface 308. At the same time, bearing interface 308 can be fluidly coupled to the interior of electric motor assembly 300. For example, lubricant may leak from bearing interface 308 into housing 302 of electric motor assembly 300. The effectiveness of operation of electric motor assembly 300 and / or chiller assembly 100 may be reduced due to lubricant leaking and collecting in undesirable locations in housing 302. As discussed further herein, operation of lubricant supply pump 312 can be adjusted to reduce the rate of friction-based heat generation to maintain a target temperature rise of bearing 304 while reducing or eliminating the possibility of lubricant leaking into housing 302.

[0020] The electric motor assembly 300 includes a temperature sensor 324. The temperature sensor 324 may be attached to the bearing 304 (e.g., on the surface of the bearing 304, within the bearing 304). The temperature sensor 324 may detect the temperature of the bearing 304. In some embodiments, the temperature sensor 324 includes at least one of a thermocouple, a resistance thermometer, and a negative temperature coefficient thermistor. The electric motor assembly 300 may include multiple temperature sensors 324 disposed at various locations of the electric motor assembly 300 including multiple bearings 304 and / or at multiple locations of one or more bearings 304.

[0021] The electric motor assembly 300 includes a controller 330. The controller 330 includes a processor 332 and a memory 334. The processor 332 may be a general or special purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable processing components. The processor 332 is configured to execute computer code or instructions stored in the memory 334 or received from another computer-readable medium (e.g., a CD-ROM, a network storage device, a remote server, etc.).

[0022] The memory 334 may include a memory for completing and / or facilitating the various processes described in this disclosure. The memory 334 may include one or more devices (e.g., memory units, memory devices, storage devices, etc.) for storing data and / or computer code. The memory 334 may include random access memory (RAM), read-only memory (ROM), hard drive storage, temporary storage, non-volatile memory, flash memory, optical memory, or any other suitable memory for storing software objects and / or computer instructions. The memory 334 may include database components, object code components, script components, or any other type of information structures for supporting various activities and described in this disclosure. The memory 334 may be communicatively coupled to the processor 332 via the controller 330 and may include computer code for performing (e.g., by the processor 332) one or more processes described herein. When the processor 332 executes instructions stored in the memory 334, the processor 332 generally configures the controller 330 to complete such activities.

[0023] The controller 330 includes a communications circuit 340. The communications circuit 340 may include a wired or wireless interface (e.g., a jack, an antenna, a transmitter, a receiver, a transceiver, a wire terminal, etc.) for implementing data communications with various systems, devices, or networks. For example, the communications circuit 340 may include an Ethernet card and port for transmitting and receiving data over an Ethernet-based communications network. As another example, the communications circuit 340 may include a WiFi transceiver for communicating over a wireless communications network. The communications circuit 340 may communicate over a local area network (e.g., a building LAN), a wide area network (e.g., the Internet, a cellular network, etc.), and / or may communicate directly (e.g., NFC, Bluetooth, etc.). In various embodiments, the communications circuit 340 may perform wired and / or wireless communications. For example, the communications circuit 340 may include one or more wireless transceivers (e.g., a Wi-Fi transceiver, a Bluetooth transceiver, an NFC transceiver, a cellular transceiver, etc.). The communication circuitry 340 may be coupled to the temperature sensor 324 to receive the temperature of the bearing 304 from the temperature sensor 324 .

[0024] Memory 334 is shown to include a temperature difference calculator 336. Temperature difference calculator 336 calculates the difference between the temperature of bearing 304 received from temperature sensor 324 and the lubricant supply temperature. Temperature difference calculator 336 may store the lubricant supply temperature as a pre-determined value. Temperature difference calculator 336 may receive the lubricant supply temperature from temperature sensor 342, which may detect the lubricant supply temperature. Temperature sensor 342 may be similar to temperature sensor 324. Temperature sensor 324 may be coupled to the lubricant supply (e.g., located within a housing of the lubricant supply) and may be positioned to detect the temperature of the lubricant before the temperature of the lubricant increases due to heat generated by interaction between shaft 212 and bearing 304.

[0025] The memory 334 is shown to include a control signal generator 338. The control signal generator 338 may generate a control signal based on the difference between the temperature of the bearing 304 and the lubricant supply temperature. The control signal generator 338 may send a control signal to the lubricant supply pump 312 to control its operation. For example, the control signal generator 338 may send a control signal to operate the lubricant supply pump 312 at a target speed.

[0026] In some embodiments, the control signal generator 338 generates the control signal based on a threshold temperature difference. The threshold temperature difference may indicate the maximum amount that the temperature of the bearing 304 can rise relative to the lubricant supply temperature. The threshold temperature difference may indicate the maximum temperature at which the bearing 304 can operate.

[0027] In some embodiments, the difference between the temperature of the bearing 304 and the lubricant supply temperature is used as the threshold temperature. The control signal generator 338 determines the lubricant flow rate to maintain the lubricant temperature below the threshold temperature difference. For example, if the difference is greater than (or equal to or greater than) the threshold temperature difference, the control signal generator 338 can increase the lubricant flow rate, and if the difference is less than (or equal to) the threshold temperature difference, the control signal generator 338 can decrease the lubricant flow rate. The control signal generator 338 may include a control function that, when executed, converts at least one of (1) the temperature of the bearing 304 and (2) the difference between the temperature of the bearing 304 and the lubricant supply temperature to a corresponding value of lubricant flow rate. In some embodiments, the control signal generator 338 may implement a control function using a lookup table or other data structure to map at least one of (1) the temperature of the bearing 304 and (2) the difference between the temperature of the bearing 304 and the lubricant supply temperature to a corresponding value of lubricant flow rate.

[0028] The control signal generator 338 may generate and send a control signal to the lubricant supply pump 312 to cause the lubricant supply pump 312 to deliver lubricant from the lubricant supply 316 to the bearing 304 (e.g., to the bearing interface 308) at the determined lubricant flow rate. For example, the control signal generator 338 may set at least one of the current, voltage, or power of the control signal to a value that causes the lubricant supply pump 312 to deliver lubricant at the determined lubricant flow rate. By adjusting the operation of the lubricant supply pump 312 based on the difference between the temperature of the bearing 304 and the supply temperature of the lubricant, the control signal generator 338 may help ensure that the temperature of the bearing 304 does not rise above desired operating conditions while reducing or eliminating the possibility of lubricant leaking from the bearing interface 308 into the motor housing 302.

[0029] 5, there is shown, among other things, a method 500 of active bearing temperature control. The method 500 may be performed using the electric motor assembly 300.

[0030] At 505, the temperature of the bearing is detected by a temperature sensor. The bearing defines a bearing interface relative to which the shaft rotates. The temperature sensor may be attached to the bearing. The temperature sensor may include at least one of a thermocouple, a resistance thermometer, and a negative temperature coefficient thermistor. The bearing may rotate the shaft relative to a stator, such as a stator that outputs a magnetic field to rotate a rotor coupled to the shaft.

[0031] At 510, the temperature of the bearing is received by a controller. The controller may include communication circuitry to receive the temperature of the bearing wirelessly or via a wired connection.

[0032] At 515, the controller determines a difference between the temperature of the bearing and a lubricant supply temperature of the lubricant supply source. The lubricant supply source is fluidly coupled to the lubricant supply pump, and at least one fluid channel is fluidly coupled to the bearing interface. The controller may at least one of store the lubricant supply temperature as a pre-determined value and receive the lubricant supply temperature from a temperature sensor coupled to the lubricant supply source or positioned to detect the lubricant supply temperature. The lubricant supply pump may include a variable speed pump.

[0033] At 520, the controller determines a lubricant flow rate based on the difference. The controller may determine the lubricant flow rate to maintain the difference at or below a threshold temperature difference. The threshold temperature difference may represent a threshold above which the temperature of the bearing becomes undesirable for operation of the chiller assembly including the bearing. If the difference indicates that the temperature of the bearing is greater than (or equal to or greater than) the threshold temperature difference, the controller may increase the lubricant flow rate. If the difference indicates that the temperature of the bearing is less than (or equal to) the threshold temperature difference, the controller may decrease the lubricant flow rate.

[0034] At 525, the controller sends a control signal to the lubricant supply pump to cause the lubricant supply pump to transport lubricant from the lubricant supply source to the bearing interface at the lubricant flow rate. The controller may identify a target speed of operation corresponding to the determined lubricant flow rate and generate the control signal to adjust the speed of operation of the lubricant supply pump, such as by setting at least one of a current, a voltage, and a power of the control signal to indicate the target speed. The controller may generate the control signal to reduce the lubricant flow rate based on the difference being greater than the threshold temperature difference.

[0035] References to "or" may be interpreted as inclusive, such that terms described using "or" can refer to either a single, a plurality, or all of the described terms. References to at least one of a list of consecutive terms may be interpreted as a disjunction, indicating either a single, a plurality, or all of the described terms. For example, a reference to "at least one of A and B" can include A only, B only, and both A and B. Such references used in combination with "comprising" or other open terminology can include additional items.

[0036] The structure and arrangement of the systems and methods shown in the various exemplary embodiments are merely illustrative. While only exemplary embodiments are detailed in this disclosure, many modifications are possible (e.g., changes in the size, dimensions, structure, shape and proportions of various elements, parameter values, mounting arrangements, amounts of materials used, colors, orientations, etc.). For example, the positions of elements can be reversed or otherwise changed, and the nature or number or location of distinct elements can be altered or changed. Accordingly, such modifications are intended to be included within the scope of this disclosure. The order or sequence of any process or method steps can be changed or resequenced according to alternative embodiments. Other substitutions, modifications, variations, and omissions can be made in the design, operating conditions, and arrangements of the exemplary embodiments without departing from the scope of this disclosure.

[0037] The present disclosure contemplates methods, systems, and program products on any machine-readable medium for performing various operations. Embodiments of the present disclosure may be implemented using an existing computer processor, by a special-purpose computer processor for a suitable system incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or storing machine-executable instructions or data structures. Such machine-readable media may be any available medium that can be accessed by a general-purpose or special-purpose computer or other machine with a processor. By way of example, such machine-readable media may comprise RAM, ROM, EPROM, EEPROM, CD-ROM, or other optical disk storage, magnetic disk storage, or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures and that can be accessed by a general-purpose or special-purpose computer or other machine with a processor. Combinations of the above media are also included within the scope of machine-readable media. Machine-executable instructions comprise, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.

[0038] Although the figures show a particular order of method steps, the order of steps may differ from that depicted. Also, two or more steps may be performed in parallel or with partial parallelism. Such variations depend on the software and hardware systems selected and the designer's choice. All such variations are within the scope of this disclosure. Similarly, software implementations may be implemented to perform various connecting steps, processing steps, comparing steps, and determining steps. This can be accomplished by standard programming techniques with rule-based logic and other logic to accomplish certain steps.

Claims

1. A shaft, a bearing defining a bearing interface about which the shaft rotates; at least one fluid channel fluidly coupled to the bearing interface; a temperature sensor for detecting the temperature of the bearing; a lubricant supply pump fluidly coupled to the at least one fluid channel for transporting lubricant from a lubricant supply source through the at least one fluid channel to the bearing interface; a controller that receives the temperature of the bearing from the temperature sensor, determines a difference between the temperature of the bearing and the lubricant supply temperature, determines a lubricant flow rate based on the difference, and sends a control signal to the lubricant supply pump to cause the lubricant supply pump to deliver the lubricant to the bearing interface at the lubricant flow rate; An electric motor assembly comprising:

2. the controller determining, based on the difference, a flow rate of the lubricant to maintain the difference at or below the threshold temperature difference. The electric motor assembly of claim 1 , comprising:

3. the controller generating the control signal to increase the flow rate of the lubricant based on the difference being greater than a threshold temperature difference. The electric motor assembly of claim 1 , comprising:

4. the lubricant supply pump includes a variable speed pump; The electric motor assembly of claim 1 , comprising:

5. The temperature sensor is attached to the bearing. The electric motor assembly of claim 1 , comprising:

6. the temperature sensor includes at least one of a thermocouple, a resistance thermometer, and a negative temperature coefficient thermistor; The electric motor assembly of claim 1 , comprising:

7. The bearing interface is fluidly coupled to the interior of the electric motor assembly. The electric motor assembly of claim 1 , comprising:

8. the controller generating the control signal to regulate the speed of the lubricant supply pump; The electric motor assembly of claim 1 , comprising:

9. determining, with a temperature sensor, a temperature of a bearing, the bearing defining a bearing interface relative to which a shaft rotates; receiving, by a controller, the temperature of the bearing from the temperature sensor; determining, by the controller, a difference between the temperature of the bearing and a supply temperature of lubricant from a lubricant supply source, the lubricant supply being in fluid communication with a lubricant supply pump; coupled, and at least one fluid channel fluidly coupled with the bearing interface; determining, by the controller, a lubricant flow rate based on the difference; sending, by the controller, a control signal to the lubricant supply pump to cause the lubricant supply pump to transport the lubricant from the lubricant supply source to the bearing interface at the lubricant flow rate; A method for active bearing temperature control, comprising:

10. determining, by the controller, a flow rate of the lubricant based on the difference to maintain the difference at or below the threshold temperature difference; 10. The method of claim 9, comprising:

11. generating, by the controller, the control signal to reduce the flow rate of the lubricant based on the difference being greater than a threshold temperature difference; 10. The method of claim 9, comprising:

12. the lubricant supply pump includes a variable speed pump; 10. The method of claim 9, comprising:

13. The temperature sensor is attached to the bearing.

10. The method of claim 9, comprising:

14. the temperature sensor includes at least one of a thermocouple, a resistance thermometer, and a negative temperature coefficient thermistor; 10. The method of claim 9, comprising:

15. generating, by said controller, said control signal to regulate the speed of said lubricant supply pump; 10. The method of claim 9, comprising:

16. one or more processors; When executed by the one or more processors, the one or more processors receiving a temperature of a bearing from a temperature sensor, the bearing defining a bearing interface and a shaft rotating relative to the bearing interface; determining a difference between the temperature of the bearing and a supply temperature of lubricant of a lubricant supply source, the lubricant supply source being fluidly coupled to a lubricant supply pump and at least one fluid channel being fluidly coupled to the bearing interface; determining a flow rate of the lubricant based on the difference; sending a control signal to the lubricant supply pump to cause the lubricant supply pump to transport the lubricant from the lubricant supply source to the bearing interface at the lubricant flow rate; a memory device containing non-transitory machine-readable instructions for causing the A controller comprising:

17. instructions for determining a flow rate of the lubricant based on the difference to maintain the difference at or below the threshold temperature difference; 17. The controller of claim 16, comprising:

18. instructions for generating the control signal to reduce the flow rate of the lubricant based on the difference being greater than a threshold temperature difference; 17. The controller of claim 16, comprising:

19. Instructions for generating the control signal to adjust the speed of the lubricant supply pump.

17. The controller of claim 16, comprising:

20. instructions for receiving the supply temperature from a supply temperature sensor; 17. The controller of claim 16, comprising:

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