| Description | Date | Identifier | |
| Temperature tests conducted on the primary windings of ignition coils for 40/50 and 20 HP chassis. | 6th Oct 1929 | Box 69 \ 1 scan0241 | |
| Comparison of running temperatures between an experimental L.C. type coil and a standard S.S. coil. | 17th Oct 1929 | Box 69 \ 1 scan0242 | |
| Correspondence regarding a replacement ballast resistance for an ignition coil on chassis 101-UF. | 17th Oct 1929 | Box 69 \ 1 scan0243 | |
| Instruction sheet detailing the examination and replacement of a ballast resistance on chassis 101.UF. | 21th Oct 1929 | Box 69 \ 1 scan0244 | |
| Faulty ballast resistance on chassis 101-UF and experiments on new nickel fuse wires. | 22th Oct 1929 | Box 69 \ 1 scan0245 | |
| Correspondence regarding an overheating ballast resistance on chassis 101-UF due to over voltage, and the dispatch of a replacement. | 22th Oct 1929 | Box 69 \ 1 scan0246 | |
| Instructions and results for coil temperature tests comparing an old standard single ballast with the present standard ballast. | 24th Oct 1929 | Box 69 \ 1 scan0247 | |
| Ignition coil temperature and charring tests on the primary winding. | 31th Oct 1929 | Box 69 \ 1 scan0248 | |
| Up-to-date literature and prices for battery ignition equipment for bench testing. | 31th Oct 1929 | Box 69 \ 1 scan0249 | |
| Response regarding the examination of a dynamo and shunt coil for chassis 101-UF. | 31th Oct 1929 | Box 69 \ 1 scan0250 | |
| Instructions and test results for an experimental ignition coil, LS8. | 11th Nov 1929 | Box 69 \ 1 scan0251 | |
| Coil endurance test failure, identifying a short circuit in the secondary layers as the cause. | 8th Dec 1924 | Box 69 \ 1 scan0252 | |
| Request to obtain enamelled secondary wire for winding six experimental ignition coils. | 2nd Nov 1929 | Box 69 \ 1 scan0253 | |
| Letter from The M-L Magneto Syndicate Ltd. regarding coil ignition sets. | 12th Nov 1929 | Box 69 \ 1 scan0254 | |
| Letter from Delco-Remy & Hyatt Ltd. regarding an enquiry for ignition coils. | 13th Nov 1929 | Box 69 \ 1 scan0255 | |
| Secondary coil winding machines observed during a visit to Messrs. North's, with suggestions for future development. | 4th Nov 1929 | Box 69 \ 1 scan0256 | |
| The experimental testing and failure analysis of various ignition coils. | 15th Nov 1929 | Box 69 \ 1 scan0257 | |
| List of instructed modifications for various coils, specifying the type of insulation to be used. | 4th Nov 1929 | Box 69 \ 1 scan0258 | |
| Request to obtain two different 12-volt ignition coils for observation of their performance and construction. | 20th Nov 1929 | Box 69 \ 1 scan0259 | |
| The experimental use of new ignition coil secondary wire from supplier McCleod and McCleod. | 21th Nov 1929 | Box 69 \ 1 scan0260 | |
| That two ignition coils should be of the latest experimental L.C. type. | 26th Nov 1929 | Box 69 \ 1 scan0261 | |
| Tolerances of secondary wire for ignition coils from various suppliers. | 27th Nov 1929 | Box 69 \ 1 scan0262 | |
| Returned faulty ignition coils with short circuits and other available primary coils. | 30th Nov 1929 | Box 69 \ 1 scan0263 | |
| Examination report on faulty ignition coils returned by customers. | 4th Dec 1929 | Box 69 \ 1 scan0264 | |
| Investigation report detailing the breakdown and faulty mechanical construction of two electrical coils. | 8th Dec 1924 | Box 69 \ 1 scan0265 | |
| Instruction sheet detailing the investigation into overheating and short-circuiting electrical coils. | 8th Dec 1924 | Box 69 \ 1 scan0266 | |
| Request for two faulty standard ignition coils to be sent for examination. | 5th Dec 1929 | Box 69 \ 1 scan0267 | |
| Supply of two types of ignition coils to Messrs. North for secondary winding. | 5th Dec 1929 | Box 69 \ 1 scan0268 | |
| Request for new finer primary ignition coils and the examination of coarser ones. | 7th Dec 1929 | Box 69 \ 1 scan0269 | |
| Two faulty ignition coils being sent for examination. | 9th Dec 1929 | Box 69 \ 1 scan0270 | |
| Examination report on faulty ignition coils returned from customers. | 10th Dec 1929 | Box 69 \ 1 scan0271 | |
| Instruction sheet detailing the examination of two faulty customer coils, identifying short circuits in the secondary winding. | 12th Dec 1929 | Box 69 \ 1 scan0272 | |
| Instructions (page 2) investigating coil failure, suggesting mechanical stress on the insulating paper as the cause. | 8th Dec 1924 | Box 69 \ 1 scan0273 | |
| Letter from Marelli Magnetos (England) Ltd. responding to an enquiry and enclosing product literature. | 13th Nov 1929 | Box 69 \ 1 scan0274 | |
| Examination of faulty coils returned from customers, detailing a partial short circuit on the secondary winding. | 13th Dec 1929 | Box 69 \ 1 scan0275 | |
| Update to the standard coil drawing to prevent faults. | 16th Dec 1929 | Box 69 \ 1 scan0276 | |
| Ignition coil failures due to secondary winding overlap. | 18th Dec 1929 | Box 69 \ 1 scan0277 | |
| Comparison and complete specification of test and measurements for experimental non-trembler ignition coils. | 23th Dec 1929 | Box 69 \ 1 scan0278 | |
| Test procedures for an ignition coil, including temperature and resistance measurements. | 23th Dec 1929 | Box 69 \ 1 scan0279 | |
| Page 3 of a testing procedure for an ignition coil, detailing high voltage and endurance tests. | 8th Jan 1930 | Box 69 \ 1 scan0280 | |
| Instruction for measuring the maximum voltage of a coil secondary using a sphere gap voltmeter. | 8th Jan 1930 | Box 69 \ 1 scan0281 | |
| Page detailing endurance and destructive testing procedures for an ignition coil. | 31th Dec 1929 | Box 69 \ 1 scan0282 | |
| Changes to the insulation of ignition coils for 20-HP & 40/50 HP chassis. | 31th Dec 1929 | Box 69 \ 1 scan0283 | |
| Test schedule and construction details for an experimental coil. | 2nd Jan 1930 | Box 69 \ 1 scan0284 | |
| Test report on electrical windings, detailing resistance, impedance, and inductance measurements. | 2nd Jan 1930 | Box 69 \ 1 scan0285 | |
| Test results and failure analysis of a coil component, detailing resistance, temperature, and current measurements. | 2nd Jan 1930 | Box 69 \ 1 scan0286 | |
| Test report page with numbered items for remarks, voltage, and gap measurements. | 2nd Jan 1930 | Box 69 \ 1 scan0287 | |
| Report page outlining remarks and the results of an examination of windings. | 3rd Jan 1930 | Box 69 \ 1 scan0288 | |
| Specification for two standard coils and their applicable date ranges and drawing numbers. | 3rd Jan 1930 | Box 69 \ 1 scan0289 | |
| Testing, risks, and standardization of battery ignition coils. | 3rd Jan 1930 | Box 69 \ 1 scan0290 | |
| Specifications for coil winding, including primary and secondary layers and insulation. | 3rd Jan 1930 | Box 69 \ 1 scan0291 | |
| Test results and failures of insulation in battery ignition coils. | 1st Jan 1930 | Box 69 \ 1 scan0292 | |
| Test schedule report detailing the design and construction of an experimental coil. | 23th Dec 1929 | Box 69 \ 1 scan0293 | |
| Test results for electrical component windings, circuits, and quantities. | 23th Dec 1929 | Box 69 \ 1 scan0294 | |
| Test sheet recording resistance, temperature, and current readings for a component. | 23th Dec 1929 | Box 69 \ 1 scan0295 | |
| Test report detailing voltage, RPM, gap measurements, and endurance test results. | 23th Dec 1929 | Box 69 \ 1 scan0296 | |
| The examination of windings following a test failure. | 15th Jan 1930 | Box 69 \ 1 scan0297 | |
| The testing of a Lucas ignition coil and the return of an M.L. and R.Bosch coil. | 15th Jan 1930 | Box 69 \ 1 scan0298 | |
| Complaint of a coil failure on Chassis GGP-2. | 15th Jan 1930 | Box 69 \ 1 scan0299 | |
| Request to prepare an experimental ignition coil with a tapped secondary winding for voltage measurement. | 16th Jan 1930 | Box 69 \ 1 scan0300 | |
| The fitment of an improved ignition coil, No. L.I.5, for the 23-EX model. | 20th Jan 1930 | Box 69 \ 1 scan0301 | |
| Construction of three ignition coils with different winding types. | 27th Jan 1930 | Box 69 \ 1 scan0302 | |
| Complete specification for testing and measuring experimental non-trembler ignition coils. | 27th Jan 1930 | Box 69 \ 1 scan0303 | |
| Test procedure for a coil, detailing temperature and resistance measurements under exaggerated operating conditions. | 27th Jan 1930 | Box 69 \ 1 scan0304 | |
| Detailed procedure for testing the performance and durability of an ignition coil. | 27th Jan 1930 | Box 69 \ 1 scan0305 | |
| Page detailing testing procedures for an electrical coil, including performance, voltage, temperature and endurance tests. | 27th Jan 1930 | Box 69 \ 1 scan0306 | |
| Page detailing endurance and breakdown testing procedures for an ignition coil. | 29th Jan 1930 | Box 69 \ 1 scan0307 | |
| Experimental spirally wound iron core for an ignition coil. | 29th Jan 1930 | Box 69 \ 1 scan0308 | |
| The examination of faulty ignition coils from Phantom and 20 HP chassis. | 10th Feb 1930 | Box 69 \ 1 scan0309 | |
| Bench tests of production type ignition coils with different secondary insulations. | 11th Feb 1930 | Box 69 \ 1 scan0310 | |
| Weaknesses and breakdowns in secondary coil windings during production. | 11th Feb 1930 | Box 69 \ 1 scan0311 | |
| Request to prepare an experimental ignition coil with tapped secondary windings for voltage measurement. | 18th Feb 1930 | Box 69 \ 1 scan0312 | |
| Faulty coil from chassis 7-WR and its subsequent repair. | 18th Feb 1930 | Box 69 \ 1 scan0313 | |
| Faulty coil received from chassis 18-OR, which has been sent for repair. | 18th Feb 1930 | Box 69 \ 1 scan0314 | |
| Faulty latest type coil, No.XH-75, from chassis 43-KR, sent to Mr. Brock for repair and remarks. | 18th Feb 1930 | Box 69 \ 1 scan0315 | |
| Faulty coil from chassis GXO-61, belonging to Hutchinson Haddow & Co. Ltd. | 18th Feb 1930 | Box 69 \ 1 scan0316 | |
| Examination report on faulty ignition coils returned from customers, detailing the cause of a short circuit. | 18th Feb 1930 | Box 69 \ 1 scan0317 | |
| Analysis of coil failures, attributing them to a combination of mechanical stress and excessive voltage. | 7th Mar 1930 | Box 69 \ 1 scan0318 | |
| Urging the production of a special ignition coil with a tapped secondary winding for voltage measurement. | 7th Mar 1930 | Box 69 \ 1 scan0319 | |
| The use of coloured cottons to distinguish coil tappings. | 21th Mar 1930 | Box 69 \ 1 scan0320 | |
| Extract from Mr. Hancock's report on 14-GIV after 14,000 miles, detailing the condition of the ignition coil and distributor. | 5th Apr 1930 | Box 69 \ 1 scan0321 | |
| Extract from a report on the performance of an ignition coil and distributor after mileage tests. | 28th Apr 1930 | Box 69 \ 1 scan0322 | |
| Specifications for two experimental ignition coils with tapped secondary windings for voltage measurement. | 7th May 1930 | Box 69 \ 1 scan0323 | |
| Voltage measurements taken on an old type ignition coil with different secondary winding connections. | 19th May 1930 | Box 69 \ 1 scan0324 | |
| Failures, investigations, and recent specification improvements related to ignition coils. | 20th May 1930 | Box 69 \ 1 scan0325 | |
| Intermittent ignition failure on a 20 HP Chassis GYL-61, requesting the faulty parts for examination. | 28th May 1930 | Box 69 \ 1 scan0326 | |
| Requesting different types of ignition coils for testing purposes. | 4th Aug 1930 | Box 69 \ 1 scan0327 | |
| Request from EFC to Mr. Brock to have a standard secondary winding wound on a coil. | 1st Sep 1930 | Box 69 \ 1 scan0328 | |
| Unsatisfactory Delco Remy ignition coil tests and failure rates. | 31th Dec 1930 | Box 69 \ 1 scan0329 | |
| Coil failures and comparing service complaint methods with Cadillac. | 1st Jan 1931 | Box 69 \ 1 scan0330 | |
| Investigation into an ignition coil failure from chassis GLN-15 which only occurs when hot, suspecting the synthetic casing material. | 1st Jan 1931 | Box 69 \ 1 scan0331 | |
| Use of bone grey fibre and spring clearance for a slipper flywheel. | 3rd Apr 1924 | Box 69 \ 1 scan0332 | |
| Requesting samples of Bone Gray Fibre for a Slipper Flywheel and other components. | 12th Apr 1924 | Box 69 \ 1 scan0333 | |
| Sourcing 'Bone Grey' American fibre as a potential new material for contact breaker rubbing blocks. | 1st May 1924 | Box 69 \ 1 scan0334 | |
| Requesting comparative machining tests on a new 'bone grey' fibre for a Goshawk distributor. | 19th May 1924 | Box 69 \ 1 scan0335 | |
| Confirming the handover of two Goshawk Distributor Rockers and reporting on machining tests of a new fibre material. | 2nd Jun 1924 | Box 69 \ 1 scan0336 | |
| Fitting and testing a 'bone-grey' fibre rubbing block on battery ignition distributors. | 2nd Jun 1924 | Box 69 \ 1 scan0337 | |
| Letter regarding the testing of a Bone Grey Fibre sample, recommended by Rolls Royce of America, for use as rubbing blocks. | 18th Jun 1924 | Box 69 \ 1 scan0338 | |
| The testing of Bone Grey Fibre against the currently used Red Fibre. | 27th Jun 1924 | Box 69 \ 1 scan0339 | |
| Comparing bone grey fibre to red fibre and Continental Bakelite, noting moisture issues on 20 HP models. | 1st Jun 1924 | Box 69 \ 1 scan0340 | |
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