# US 8,541,909 B2 · System having a variable frequency power distribution bus for driving a variable speed motor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,909 B2 - Document ID: US8541909B2 - Status: Granted - Kind: B2 - Application number: 13/169,883 - Filed: 2011-06-27 - Published: 2011-10-20 - Granted: 2013-09-24 - Earliest claimed: 2008-01-17 - Assignees: DRS Power Technology, Inc. - Applicants: Richard Armstrong; Edgar Thaxton - Inventors: Richard Armstrong; Edgar Thaxton - Web page: https://patentgrep.com/patent/US8541909B2 ## CPC - B60L 50/13: using AC generators and AC motors - B60L 2200/32: Waterborne vessels - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A system and method for supplying power to a variable speed motor for rotating a shaft may include generating an A/C output having a variable frequency corresponding to speed of a prime mover, where the speed of the prime mover is equal to or greater than a predetermined speed limit. The A/C output of the prime mover may be distributed to the variable speed motor such that the speed of the variable speed motor is varied relative to the frequency of the A/C output. The variable speed motor may be electrically disconnected from the A/C power when the speed of the prime mover being used to drive the variable speed motor is equal to or within a predetermined range of the predetermined speed limit. An alternate A/C output may be distributed to the variable speed motor after the A/C power is electrically disconnected from the variable speed motor. ## Claims ### Claim 1 A method for supplying power to a variable speed motor for rotating a shaft, comprising: generating an A/C output having a variable frequency corresponding to speed of a prime mover, the speed of the prime mover being equal to or greater than a predetermined speed limit; distributing the A/C output of the prime mover to the variable speed motor such that the speed of the variable speed motor is varied relative to the frequency of the A/C output; electrically disconnecting the variable speed motor from the A/C power when the speed of the prime mover being used to drive the variable speed motor is equal to or within a predetermined range of the predetermined speed limit; and distributing an alternate A/C output to the variable speed motor after the A/C power is electrically disconnected from the variable speed motor. ### Claim 2 (depends on 1) The method according to claim 1, wherein distributing the alternate A/C output includes distributing the alternate A/C output to the variable speed motor when the speed of the prime mover is less than the predetermined speed limit. ### Claim 3 (depends on 1) The method according to claim 1, further connecting the alternate A/C output to the variable speed motor via a different conductive path than a conductive path that delivers the A/C power to the variable speed motor when the speed of the prime mover is less than the predetermined speed limit. ### Claim 4 (depends on 1) The method according to claim 1, further comprising: generating a single frequency A/C output based on the variable frequency A/C output of the prime mover; and driving an auxiliary load with the single frequency A/C output. ### Claim 5 (depends on 1) The method according to claim 1, wherein distributing the alternate A/C output to the variable speed motor includes distributing the alternate A/C output in a parallel manner with respect to the A/C output. ### Claim 6 (depends on 5) The method according to claim 5, further comprising: electrically disconnecting the A/C output from the variable speed motor; and distributing the alternate A/C output to the variable speed motor after the variable speed motor is disconnected from the A/C output. ### Claim 7 (depends on 1) The method according to claim 1, further comprising distributing the A/C output and alternate A/C output to a second variable speed motor. ### Claim 8 (depends on 1) The method according to claim 1, wherein distributing the A/C output and alternate A/C output to the second variable speed motor includes distributing the A/C output and alternate A/C output to the second variable speed motor in series with the variable speed motor. ### Claim 9 A method for supplying power to a variable speed motor for rotating a shaft, comprising: generating a plurality of A/C outputs having respective variable frequencies corresponding to the speed of the respective prime mover, the speed of each of the prime movers being equal to or greater than a predetermined speed limit, selectively varying speed of the variable speed motor relative to the frequency of the combined A/C outputs of the prime movers; electrically disconnecting the variable speed motor when the speed of a prime mover being used to drive the variable speed motor is equal to or within a first predetermined range of the predetermined speed limit; and distributing an alternate A/C output to the variable speed motor after the variable speed motor is disconnected. ### Claim 10 (depends on 9) The method according to claim 9, wherein distributing the alternate A/C output to the variable speed motor includes distributing the alternate A/C output in a parallel manner with respect to the A/C output. ### Claim 11 (depends on 9) The method according to claim 9, further comprising: electrically disconnecting the A/C output from the variable speed motor; and distributing the alternate A/C output to the variable speed motor after the variable speed motor is electrically disconnected from the A/C output. ### Claim 12 (depends on 9) The method according to claim 9, further comprising distributing the A/C output and alternate A/C output to a second variable speed motor. ### Claim 13 (depends on 12) The method according to claim 12, wherein distributing the A/C output and alternate A/C output to the second variable speed motor includes distributing the A/C output and alternate A/C output to the second variable speed motor in series with the variable speed motor. ### Claim 14 (depends on 9) The method according to claim 9, further comprising: generating a single frequency A/C output based on the variable frequency A/C output of the prime mover; and driving an auxiliary load with the single frequency A/C output. ### Claim 15 (depends on 9) The method according to claim 9, wherein distributing the alternate A/C output includes distributing the alternate A/C output to the variable speed motor when the speed of the prime mover is less than the predetermined speed limit. ### Claim 16 A method of manufacturing a power distribution system for supplying power to a variable speed motor for rotating a shaft, said method comprising: providing a variable speed prime mover adapted to generate an A/C output having a variable frequency corresponding to the speed of the prime mover; electrically connecting a power switch to the variable speed prime mover; electrically connecting a power distribution bus to the A/C output of the prime mover and, via the power switch, to the variable speed motor; electrically connecting a variable frequency drive to the A/C output of the prime mover via the power distribution bus; and electrically connecting a transformer to the power distribution bus; and electrically connecting a second variable frequency drive to the transformer to provide for driving auxiliary loads. ### Claim 17 (depends on 16) The method according to claim 16, further comprising connecting a controller to the power switch and to the variable frequency drive, the controller, when operated, is configured to selectably engage and disengage the power switch to apply and remove the A/C output from the variable speed motor. ### Claim 18 (depends on 17) The method according to claim 17, further comprising: electrically connecting a second power switch between the variable frequency drive and the variable speed motor; and electrically connecting the controller to the second power switch, wherein the controller is configured to engage and disengage the second power switch in a substantially opposite manner to that of the power switch. ### Claim 19 (depends on 16) The method according to claim 16, further comprising connecting a second variable speed motor to the power distribution bus.