NUWC_851903-1 Defiant Motor Magnetics Specification.docx

NUWC_851903-1 Defiant Motor Magnetics Specification

14 April 2020

Prepared by:

John Raposa Naval Undersea Warfare Center (NUWC) Division Newport

DISTRIBUTION STATEMENT D: Distribution authorized to the Department of Defense and U.S. DoD contractors only; Critical Technology, November 2017. Other requests shall be referred to Naval Undersea Warfare Center, Division Newport, Code 85.

RECORD OF CHANGE

i

NUWC_851903-1 Defiant Motor Magnetics Specification

A. Stator/Rotor Dimensions

a. The stator and rotor components shall be fabricated per the dimensions listed in the 851903-1 Drawing Package supplied in Appendix A.

B. Stator Fabrication

a. Stator Backiron

i. The outer diameter of the stator lamination stack shall be ground for a precision shrink fit per the lamination assembly drawing 851903-1-4102 included in Appendix A.

b. Stator Lamination

i. The laminations shall be fabricated be per the lamination drawing 851903-1-4112 included in Appendix A.

c. Stack Height Tolerance

i. The stack height tolerance shall meet the dimensions listing in the lamination assembly drawing 851903-1-4102 included in Appendix A.

d. Slot Liner Material

i. The stator slot liner material and requirements are provided in the stator assembly drawing 851903-1-4103 included in Appendix A.

C. Stator Windings

a. Stator Configuration

i. The stator phases shall be connected in a wye-configuration.

ii. The 7 coils that make up each phase shall be wound in a single path. The path will consist of seven coils in series. This topology is shown in figures 1-3 and tables 1-3 for each of the three phases (A1, B1, and C1). The motor phases shall be driven by a single three-phase set of power electronics.

iii. One lead end of each of the phases shall be brought out of the motor through the forward end turn. Therefore, a total of 3 phase leads shall be brought out the forward end turns of the magnetics. A phase lead exit drawing is supplied in the stator assembly drawing 851903-1-4103 included in Appendix A. The other end of each phase shall be connected to a single neutral which will reside in the forward end turns.

iv. The winding tables for each phase are shown in Tables 1-3.

1. The green slot number listed in the Go column in each winding table, indicates the coil lead that needs to be brought out of the motor.

2. The red slot number in the Return column in each winding table indicates the coil lead that needs to be connected to the motor neutral for that specific phase.

3. Each slot contains two layers of windings. Each layer contains three turns.

Figure 1: Phase Winding Diagram for Phase A

Figure 2: Phase Winding Diagram for Phase B

Figure 3: Phase Winding Diagram for Phase C

Table 1: Winding Table (Phase A)

Table 2: Winding Table (Phase B)

Table 3: Winding Table (Phase C)

v. The following provides further description as to how each phase is wired. The green numbers indicate the end of each phase that needs to be brought out the front of the motor via the forward end turn. The red numbers indicate the end of each phase that need to be connected to the motor neutral inside the forward end turn.

1. Phase A1:

a. Enters slot 9 and returns from slot 5 (Connected to Neutral N)

2. Phase B1:

a. Enters slot 15 and returns from slot 11 (Connected to Neutral N)

3. Phase C1:

a. Enters slot 21 and returns from slot 17 (Connected to Neutral N)

vi. Coil Placement in the slot

1. The coils shall be placed in the slot in the locations supplied in figure 4.

2. As stated earlier, the slot contains two layers. Each layer will occupy either the slot top (near the tooth opening) or the slot bottom (near the stator backiron).

Figure 4: Coil Placement in the Stator Slots

vii. External Phase Leads

1. All phase windings shall be brought out the forward end of the motor magnetics

2. The three phases shall be brought out at the locations specified in the stator assembly drawing 851903-1-4103 included in Appendix A.

3. All phases shall be properly labelled. This is critical to ensure proper connection to the appropriate power electronics inverter and phase.

4. Figure 5 shows the 3 separate phase lead connections external to the motor magnetics. The 3 leads shall be labelled as shown in figure 5.

a. The diagram shows the three phases which comprise the motor windings. Each set coils will have one end brought out of the motor.

b. Slot numbers are provided on the phase lead end of each coil group in order to assist with coil bundling of the phase lead connections.

viii. Neutral Connection

1. The neutral, N, of the wye configuration, shall be terminated by the manufacturer and will be located on the forward end of the magnetics.

2. The neutral connection shall be potted in the forward end turn.

3. The neutral connection is shown in figure 5.

a. The diagram shows the three phases which comprise the motor winding. Each coil will have one end connected to the neutral connection inside the motor.

b. Slot numbers are provided on the neutral end of each coil to assist with coil bundling of the neutral connection.

Figure 5: External Phase Lead and Neutral Connections

b. Wire Selection to Wind Stator

i. The wire selection shall be per drawing the stator assembly drawing 851903-1-4103 included in Appendix A.

c. External Phase Lead Termination Wire

i. Three feet of additional phase winding length shall be supplied external to the lamination stack.

d. Thermistors

i. Six thermistors shall be installed in the stator magnetics during the winding process. The stator assembly drawing 851903-1-4103 shows the slot numbers and locations of the six thermistors. The thermistor type and model number is supplied in drawing.

ii. The slot thermistors shall be placed near the center of the slot. The actual distance of the thermistor to the slot bottom/stator back iron interface shall be measured and recorded. The axial distance of the slot thermistors from the forward stack face shall also be measured.

iii. The end turn thermistors shall be placed in the end turns in close proximity to their identified phases and slot number shown in drawing 851903-1-4103. There shall be two thermistors mounted in the forward end turns and one thermistor mounted in the aft end turn. The leads for the aft end turn thermistor shall be brought forward through the motor via the slot specified. The locations of all thermistors are identified in drawing 851903-1-4103.

iv. All thermistor leads shall be labelled with the slot number and location (slot or end turn).

v. The twelve thermistor leads (6 pairs) shall be bundled together, before potting, and brought out through the forward end turn at a location that is specified in drawing 851903-1-4103.

D. Stator Potting

a. Potting Material

i. The stator shall be potted per drawing 851903-1-4103.

b. Potting Fixture

i. The contractor shall design and fabricate the required potting fixture for the stator assembly E. Rotor Backiron

a. The rotor backiron shall be fabricated per the rotor backiron drawing 851903-1-4111 included in Appendix A.

F. Rotor Band/Wrap

a. The outer diameter of the rotor magnets shall be wrapped with carbon fiber thread per the rotor assembly drawing 851903-1-4111 included in Appendix A.

G. Magnets

a. Magnetic Component Engineering (MCE) N4471 Magnets shall be used

i. A data sheet is shown in figure 6.

ii. Magnets shall be fabricated per dimensions shown in the rotor magnet drawing 851903-1-4113 included in Appendix A.

iii. The magnets can be manufactured in up to 2 pieces to satisfy the stack length requirement

iv. A test report shall be supplied with the magnet delivery

Figure 6: MCE N4471 Permanent Magnet Data Sheet

H. Rotor Backiron Inner Diameter (ID)

a. The backiron inner diameter must meet the dimensions shown in the rotor backiron drawing 851903-1-4111 included in Appendix A.

I. Shaft Rotation

a. Looking forward from the aft end: Counter-clockwise

Appendix A

NUWC_851903-1 Defiant Motor Drawing Package DISTRIBUTION STATEMENT D: Distribution authorized to the Department of Defense and U.S. DoD contractors only; Critical Technology, November 2017. Other requests shall be referred to Naval Undersea Warfare Center, Division Newport, Code 85.

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