| Description | Date | Identifier | |
| Authorizing the withdrawal of 12 sets of Dynamo Brushes from production stock. | 3rd Feb 1939 | Box 166 \ 2 img248 | |
| Regulator part sent to the makers for examination. | 24th Feb 1939 | Box 166 \ 2 img249 | |
| Correspondence regarding a dynamo fault and potential solder melting point issue on Chassis No. 3.BT-65 for a Mr. Denis Becker. | 5th Apr 1939 | Box 166 \ 2 img250 | |
| Letter to Joseph Lucas Ltd. detailing the results of tests on six RR1 type regulators. | 12th May 1939 | Box 166 \ 2 img251 | |
| Page two of a letter to Joseph Lucas Ltd. regarding issues with unit performance during a heating run. | 12th May 1939 | Box 166 \ 2 img252 | |
| Test results for six Lucas RR.1 type regulators, tested against a specific specification. | 18th Jan 1939 | Box 166 \ 2 img253 | |
| Sourcing C.A.V. type regulators for the last 40 Wraith cars. | 22th Aug 1939 | Box 166 \ 2 img254 | |
| The Lucas regulator on the Dash Ripplet. | 12th Mar 1940 | Box 166 \ 2 img255 | |
| Technical description and diagram of the 'Newtons' voltage regulator, with comparisons to other types. | 15th Apr 1941 | Box 166 \ 2 img256 | |
| Cover note for the attached production test specification for a 20/25 Switchbox. | 20th Oct 1931 | Box 166 \ 3 img001 | |
| Specification of test for a 20/25 switchbox. | 16th Oct 1931 | Box 166 \ 3 img002 | |
| Set of instructions for testing electrical circuits and connections using switches and terminals. | 26th Oct 1932 | Box 166 \ 3 img003 | |
| Parts list and instructions for modifying the switchbox to isolate the ignition on 20/25 HP and Peregrine II models. | 26th Oct 1932 | Box 166 \ 3 img004 | |
| Alteration 737/Dss for the 20/25 and Peregrine II switchbox. | 15th Nov 1932 | Box 166 \ 3 img005 | |
| Alteration notice for the Peregrine II and 20/25 HP switchbox used with a C.A.V. Regulator. | 18th Nov 1932 | Box 166 \ 3 img006 | |
| Difficulties and potential solutions for isolating starter motor circuits on Phantom II and 20/25 models. | 1st Dec 1932 | Box 166 \ 3 img007 | |
| Confirming the proposed design for the Peregrine switchbox and instrument patch. | 16th Dec 1932 | Box 166 \ 3 img008 | |
| The design of a new switch-box to prevent battery discharge on various models. | 28th Dec 1932 | Box 166 \ 3 img009 | |
| Outlining five points of concern regarding a vehicle's wiring diagram. | 28th Dec 1932 | Box 166 \ 3 img010 | |
| Suggestion for the operation of the ignition switch to include a warning lamp indicating the key has not been turned off. | 28th Dec 1932 | Box 166 \ 3 img011 | |
| Features and development of a grouped instrument panel for the Peregrine. | 11th Jan 1933 | Box 166 \ 3 img012 | |
| Suggestion to use an improved scheme on both the Peregrine and 20/25 car models. | 8th Dec 1933 | Box 166 \ 3 img013 | |
| Request to overhaul a switchbox on vehicle 20-EX due to a faulty dynamo contact. | 8th Dec 1933 | Box 166 \ 3 img014 | |
| Design and functionality of a new switchbox, including alterations for dual ignition. | 16th Feb 1934 | Box 166 \ 3 img015 | |
| Estimated cost saving of 30 shillings for a new switchbox design. | 19th Feb 1934 | Box 166 \ 3 img016 | |
| Confirming a cost saving of 30 shillings per chassis resulting from a new switchbox design. | 20th Feb 1934 | Box 166 \ 3 img017 | |
| Querying contradictions in the operation of a switchbox, specifically regarding the starter circuit, parking lights, and instrument board lights. | 22th Feb 1934 | Box 166 \ 3 img018 | |
| Follow-up request for a reply to queries regarding a switchbox. | 5th Mar 1934 | Box 166 \ 3 img019 | |
| Technical memorandum replying to queries about the functionality of a vehicle's switchbox. | 7th Mar 1934 | Box 166 \ 3 img020 | |
| Concluding that a scheme to reduce illumination by halving the current is not justified by the result. | 7th Mar 1934 | Box 166 \ 3 img021 | |
| Design of the instrument panel switchbox and a new walnut panel layout. | 14th Mar 1934 | Box 166 \ 3 img022 | |
| Progress and model availability of the Spectre Switchbox. | 18th Jul 1934 | Box 166 \ 3 img023 | |
| Examination and test report on the first Spectre Switchbox, providing suggestions for improvement. | 31th Jul 1934 | Box 166 \ 3 img024 | |
| Technical report on observed weaknesses and proposed modifications to electrical contacts, including a dynamo circuit sparking test. | 31th Jul 1934 | Box 166 \ 3 img025 | |
| Recommendations for improvements to starter switch contacts and ignition switch levers. | 31th Jul 1934 | Box 166 \ 3 img026 | |
| Standardisation of parts report for a Switchbox to D.54325. | 21th Aug 1934 | Box 166 \ 3 img027 | |
| The deterioration of rubber sleeves on switchbox terminals with a suggestion for a replacement material. | 7th Sep 1934 | Box 166 \ 3 img028 | |
| Requesting the construction of a switchbox for the 'Spectre' chassis, listing required parts. | 17th Sep 1934 | Box 166 \ 3 img029 | |
| Continuation page of a parts list detailing drawing numbers, part names, and a note for the Pattern Shop. | 17th Sep 1934 | Box 166 \ 3 img030 | |
| Parts list for the 'Spectre' 31.EX Switchbox, section 8160, detailing components and their drawing numbers. | 13th Dec 1934 | Box 166 \ 3 img031 | |
| Continuation list of drawing numbers and their corresponding part names. | 13th Dec 1934 | Box 166 \ 3 img032 | |
| Listing part numbers for the 'Spectre' 31.EX switchbox, section 8160. | 13th Dec 1934 | Box 166 \ 3 img033 | |
| List of parts for Switchbox Section 8160, 'Spectre' 31.EX, R.R.Scheme 781. | 18th Dec 1934 | Box 166 \ 3 img034 | |
| Listing additional parts required for the 'Spectre' 21.EX Switchbox. | 27th Dec 1934 | Box 166 \ 3 img035 | |
| Confirmation of required parts for the 'Spectre' 31.EX Switchbox, specifically a Brush Stamping, and a note regarding blueprints. | 2nd Jan 1935 | Box 166 \ 3 img036 | |
| Request to put in hand a Switchbox Flex Flange for a 'Spectre' III to match new dashboard castings. | 27th Mar 1935 | Box 166 \ 3 img037 | |
| Experimental department report on bench tests of a Spectre switchbox. | 2nd May 1935 | Box 166 \ 3 img038 | |
| Bench test report on a modified Spectre switchbox to assess current carrying capacity and volt drop. | 2nd May 1935 | Box 166 \ 3 img039 | |
| The production specification for inspection and test of the Phantom III switchbox. | 29th Nov 1935 | Box 166 \ 3 img040 | |
| Specification for the inspection, adjustment, and testing of the switchbox for the Phantom III model. | 26th Nov 1935 | Box 166 \ 3 img041 | |
| Procedure for testing the correctness of switching operations. | 16th Feb 1937 | Box 166 \ 3 img042 | |
| Instruction to trial rubber tubing as a substitute for flexible metal tubing for the switchbox wiring conduit on Chassis 36 Ex. | 16th Feb 1937 | Box 166 \ 3 img043 | |
| The replacement of metallic flexible tubing with a rubber tube for the switchbox on Phantom III & 25/30 HP models. | 18th Feb 1937 | Box 166 \ 3 img044 | |
| Requesting the fitting of a new switchbox to Chassis 35-EX. | 2nd Jul 1937 | Box 166 \ 3 img045 | |
| Request for parts to be made for a modification to a PH.III switchbox push button. | 2nd Jul 1937 | Box 166 \ 3 img046 | |
| Notification about new blueprints for Wraith III switchbox parts suitable for the Lucas L.R.7.T. Regulator. | 15th Jul 1937 | Box 166 \ 3 img047 | |
| Request for carbon contacts for 'Phantom III' switchbox experiments to prevent breakages. | 14th Aug 1937 | Box 166 \ 3 img048 | |
| Modification to a Phantom III starter switch, including a list of new parts required for testing. | 24th Aug 1937 | Box 166 \ 3 img049 | |
| Modification to the Starter Switch for Phantom III and 25/30 HP models to improve the connection of the carbon contacts. | 26th Aug 1937 | Box 166 \ 3 img050 | |
| Request for a new experimental switchbox for a Bentley chassis, detailing the parts and intended chassis. | 8th Sep 1937 | Box 166 \ 3 img051 | |
| Requesting a slight modification to the switchbox on car 36.EX. | 11th Sep 1937 | Box 166 \ 3 img052 | |
| Switchbox modification for the Wraith and other models, adding a short-circuiting device for the ballast resistance. | 4th May 1938 | Box 166 \ 3 img053 | |
| The replacement of switchbox components with new parts and associated blueprints. | 19th Apr 1939 | Box 166 \ 3 img054 | |
| List of modifications required to improve the action of the lighting and ignition switches for specific Bentley chassis. | 20th Apr 1939 | Box 166 \ 3 img055 | |
| Instructions detailing a change of lever type, cancellation of a previous memo, and distribution of switches for testing. | 20th Apr 1939 | Box 166 \ 3 img056 | |
| Confirmation memo regarding the handover of blueprints for a Bentley V Lighting Switch Lever. | 25th Apr 1939 | Box 166 \ 3 img057 | |
| 10,000 miles test for the New Phantom, addressing oil damage to a cable. | 25th Jan 1925 | Box 166 \ 4 img001 | |
| Requesting an update on electrical failures during a 10,000-mile test. | 20th Nov 1925 | Box 166 \ 4 img002 | |
| Correct lamp bulbs for the 40/50 New Phantom, 20 HP, and Silver Ghost models. | 9th Dec 1925 | Box 166 \ 4 img003 | |
| Chassis 10-GIII after 2948 miles, detailing issues and performance of the electrical fittings. | 12th Apr 1926 | Box 166 \ 4 img004 | |
| Letter from coachbuilder Hooper & Co. regarding the supply of lamps and a horn for a Saloon Cabriolet on chassis No.10-G3. | 15th Jul 1927 | Box 166 \ 4 img005 | |
| Request to coachbuilders Messrs. Hoopers to supply headlamps and wing lamps for a 30 HP car. | 19th Jul 1927 | Box 166 \ 4 img006 | |
| Compromise for the position of headlamps on the 20 HP model due to a higher radiator. | 19th Jun 1928 | Box 166 \ 4 img007 | |
| The front and rear wheel clearances for the India 3 model. | 26th Jun 1923 | Box 166 \ 4 img008 | |
| New headlamp supports for the 20 HP chassis due to a higher radiator. | 10th Jul 1928 | Box 166 \ 4 img009 | |
| Fitting a Stephan Grebal spot light, a smaller headlamp, and Chrysler type wing lamps. | 16th Jul 1928 | Box 166 \ 4 img010 | |
| Standardisation of headlamp positions on the 20 HP Chassis. | 16th Jul 1928 | Box 166 \ 4 img011 | |
| Height and appearance of headlamps on a 20 HP Chassis. | 9th Jul 1928 | Box 166 \ 4 img012 | |
| Arrangement, types, and switching of lamps for the 12-G-4 model. | 17th Jul 1928 | Box 166 \ 4 img013 | |
| Proposal to use a Bosch changeover foot switch for headlight control on a Barkerlite Coupe. | 19th Jul 1928 | Box 166 \ 4 img014 | |
| Correspondence approving the improved headlamp position for the 20 HP Chassis. | 31th Jul 1928 | Box 166 \ 4 img015 | |
| Correspondence regarding the supply of suitable headlamps for the 20 HP chassis from Joseph Lucas Ltd. | 18th Sep 1928 | Box 166 \ 4 img016 | |
| Letter from Joseph Lucas Ltd regarding the supply and testing of Lucas R.160.S lamps for the 20 HP Chassis. | 17th Sep 1928 | Box 166 \ 4 img017 | |
| Standardisation of chassis parts concerning the raising of 20 HP headlamps. | 3rd Sep 1928 | Box 166 \ 4 img018 | |
| Form for tracking the introduction and costs of a new standardized chassis part. | 2nd Sep 1928 | Box 166 \ 4 img019 | |
| Potential standardisation of the new large Lucas headlamp, type RB.160, for the 20 HP car. | 1st Oct 1928 | Box 166 \ 4 img020 | |
| Requesting a report on the testing of Lucas R.160.S type headlamps for the 20 HP chassis. | 1st Oct 1928 | Box 166 \ 4 img021 | |
| Choice of lamps for the 20 HP and 40/50 models. | 4th Oct 1928 | Box 166 \ 4 img022 | |
| Standardisation of headlamps, comparing Lucas P.100 and RB-160 models. | 1st Oct 1928 | Box 166 \ 4 img023 | |
| Typed memo concerning the standardisation of a new R.160.S headlamp for the 20 HP car. | 10th Oct 1928 | Box 166 \ 4 img024 | |
| Communication regarding Joseph Lucas Limited's development of smaller P.100 headlamps for the 20 HP chassis. | 25th Oct 1928 | Box 166 \ 4 img025 | |
| Standardization of headlamps for the 20 HP chassis. | 26th Oct 1928 | Box 166 \ 4 img026 | |
| Letter to Messrs. Lucas inquiring about modifications made to the 160.S. lamp for the 20 HP car. | 29th Oct 1928 | Box 166 \ 4 img027 | |
| Instructions regarding the fitting of lamps for a Barkerlite Coupe and a Hooper Sedanca. | 7th Nov 1928 | Box 166 \ 4 img028 | |
| Extract detailing the specifications for headlamp brackets and Lucas headlamps with electrical dipping reflectors for chassis 12-G4. | 30th Nov 1928 | Box 166 \ 4 img029 | |
| Design and fitting of a single wheel carrier for the rear of a vehicle. | 3rd Dec 1928 | Box 166 \ 4 img030 | |
| Responding to a telegram about a delay in sending a Bosch two-way switch for an experimental car. | 8th Dec 1928 | Box 166 \ 4 img031 | |
| List of accessories for a Closed Coupled All Weather Barker, model 16-G-4. | 8th Dec 1928 | Box 166 \ 4 img032 | |
| Reporting the breaking of front wing stays on a 20 HP car due to the weight of the headlamps. | 3rd Jan 1929 | Box 166 \ 4 img033 | |
| Design specifications for a G.4. close coupled four-seater allweather car, covering aspects from body dimensions to colour schemes. | 1st Feb 1929 | Box 166 \ 4 img034 | |
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