ELECTRIC TRACTION MOTORS

Innovative high efficiency electric transmission

 

 

 

Slipery hulls improve vessel performance, micro bubble librication

 

 

MOTORS - Introduction

For an efficient ship, we need efficient motors. Cost and complexity too are important considerations. Before deciding what motor SolarNavigator should be fitted with, we should consider the latest advances in design. Synchronous DC motors would be an obvious choice, if it were not for the complication of the electronics - and yet several manufacturers supply these motors as drives where reliability is paramount, such as submersibles.

 

On the other hand there are very efficient DC motors such as the Lynch, with a very high power to weight ration and proven reliability. These motors are brushed and it is the brushes and commutator materials that determine operational life. Inevitably, brushes will need servicing. So we must look at the mission parameters to see if DC brushed motors could provide the service requirement on a world circumnavigation.

 

 

 

FLEXIBILITY

 

To make the most of excess energy at peak charge times and to use stored energy for the best range, it is sometimes necessary to engage a higher output motor with reduced gearing - when excess energy cannot be stored, and at other times, when running on stored energy for prolonged periods, to engage a lower output motor with higher gearing. The graph below makes this plain. A designer should aim to keep motor reduction ratio choice in the crimson band for peak efficiency. This is basic good design.

 

 

SECONDARY MOTORS

 

For an ultra reliable autonomous robot boat, we need back-up motors. If one motor set fails, we might engage another set. Compared to the long term energy savings, the additional setup costs are insignificant.

 

 

EMERGENCY MOTORS

 

Where we are cruising at relatively slow speeds, there are times when more power is needed, such as in tidal conditions, to avoid collisions, when docking, or just because we are late. By having the ability to engage and disengage motor sets without mechanical losses from layshafts and bearings, the SolarNavigator can operate at peak efficiency in real time. We cannot show you how we achieve this here because the method is patentable and patent applied for.  

 

 

A GRAPH USED TO ESTIMATE BEST MOTOR REDUCTION RATIOS FOR DC MOTOR COMBINATIONS

 

 

VOLTS

RPM

3:1

knots

4:1

knots

5:1

knots

6:1

knots

7:1

knots

8:1

knots

9:1

knots

Efficiency%

12

1,000

333

4

250

3

200

2.4

166

2

143

1.7

125

1.5

111

1.33

25

18

1,500

500

6

375

4.5

300

3.6

250

3

214

2.5

187

2.25

166

2

37

24

2,000

666

8

500

6

400

4.8

333

4

286

3.4

250

3

222

2.66

50

30

2,500

832

10

625

7.5

500

6

416

5

357

4.2

312

3.75

277

3.33

62

36

3,000

1000

12

750

9

600

7.2

500

6

428

5.1

375

4.5

333

4

75

42

3,500

1165

14

875

10.5

700

8.4

583

7

500

6

437

5.25

388

4.66

88

48

4,000

1332

16

1000

12

800

9.6

666

8

571

6.8

500

6

444

5.33

92

54

4,500

1498

18

1125

13.5

900

10.8

750

9

642

7.6

562

6.75

500

6

-

60

5,000

1665

20

1250

15

1000

12

833

10

714

8.5

625

7.5

555

6.66

-

66

5,500

1830

22

1375

16.5

1100

13.2

917

11

785

9.3

687

8.25

610

7.32

-

72

6,000

2000

24

1500

18

1200

14.4

1000

12

856

10.1

750

9.0

666

7.98

-

 

 

 

Motor/Kw

Configuration

60Kw (80.4hp)

40Kw (53.6hp)

30Kw (40.2hp)

20Kw (26.8hp)

15Kw (20.1hp)

10Kw (13.3hp)

7.5Kw (10.0hp)

 

 

 

 

 

 

 

DC BRUSHED MOTORS

 

The configuration we are looking at requires integration with the transmission. That may also be so for synchronous motors, depending in what is available off the shelf. We do not want to get involved in development where that is not necessary.

 

..

 

 

DC SYNCHRONOUS MOTORS

 

..

 

 

RELIABILITY

 

For an autonomous robot nothing is more important than dependability.....

 

 

STAND BY FAILSAFE

 

Should any one of the main drive motors fail, the proposed design will allow several options to keep the craft powered.

 

The SolarNavigator team hope to be able to run tests on as many of the above and report those findings in the years ahead.

 

 

LINKS

 

Connect innovateuk vessel efficiency competition

 

 

 

 

Email: Brian Dusart at Max Energy Ltd:  

 

Phone UK: + 44 (0) 1323 831727    +44 (0) 7842 607865

Max Energy Limited in association with Blueplanet Productions

Solar House, BN27 1RF, United Kingdom

 

  

 

PROJECT LINKS

 

 

Alloys

Paints - Coatings

Autonomy - Computers - Software

Project Estimates

Batteries

Project Objectives

Composites

PR Events - 

Construction - Modular

Propeller

Diving - Hull survey & repair

Record Attempt

Electronics - Collision Avoidance COLREGS

Screens - 

Galley - 

Solar Arrays - tracking theory PIC PCB  MPPT PV trackers  Actuators & circuits

Hydraulics - Active hull - 

Stealth - Scorpion laser - Mine hunter

Hull Design - Capsize - SWASSH - Lubrication - Mass

Timber - 

Life Support - 

Tank Testing - Open water collision avoidance

Model ConstructionHulls - Wings - W'gens - ROV - AI

Tooling - 

Motors - DC v AC synchronous

Transmission - gearing & prop shaft/seals

Navigation  - Oceanographic Hydrographic Surveying

Treasure hunting - marine archaeology

Paints - Antifouling

Wind Turbines -

 

 

 

 

 

 Kulo Luna, a John Storm adventure featuring the Solarnavigator, by Jameson Hunter

 

The design of the Solar Navigator boat has been licensed for use in

the John Storm series of books by Jameson Hunter

 

 

This website is copyright © 2013 Electrick Publications. All rights reserved. The bird logo and names Solar Navigator and Blueplanet Ecostar are trademarks ™.  The Blueplanet vehicle configuration is registered ®.  All other trademarks hereby acknowledged and please note that this project should not be confused with the Australian: 'World Solar Challenge'™which is a superb road vehicle endurance race from Darwin to Adelaide.  Max Energy Limited is an educational charity working hard to promote world peace.

 

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