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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Correspondence regarding a dynamo fault and potential solder melting point issue on Chassis No. 3.BT-65 for a Mr. Denis Becker.

Identifier  ExFiles\Box 166\2\  img250
Date  5th April 1939
  
6092
CHILDS
W/S - C.
c. to Rm.{William Robotham - Chief Engineer}
c. to Mx.{John H Maddocks - Chief Proving Officer}
c. to N.
c. to Hd.{Mr Hayward/Mr Huddy}
c. to By/RD
c. to D/BP.

BY/SB.{Mr Bull/Mr Bannister}1/MG.5.4.39

CHASSIS NO. 3.BT{Capt. J. S. Burt - Engineer}-65 - Denis Becker

Thanks for your H.8/H.4.5.39, from which it would appear that there may still be time to despatch a new regulator to Messrs. Erdmann & Rossi in Berlin. A suitable regulator has now been chosen to protect the dynamo against any excessive output under full load. We are handing this regulator to D/BP for despatch to Berlin.

We are rather interested in the question of the melting point of the solder, as raised by the repairers in Munich, and it is quite possible that this is a contributory cause of the trouble which has been experienced, since all the trouble with the Phantom III dynamo has been due to the heat generated being sufficient to melt the solder but this has not resulted in the armature winding having been damaged or the insulation having been burnt in any way. We are therefore looking into the possibility of using a higher melting point solder.

In view of the foregoing, we think it is quite an advantage for Mr. Becker to use the original dynamo now it has been repaired, to see if this will stand up any better than the previous ones.

At the same time we should point out that the melting point of the solder we use is already about 170°C, which is far in excess of any temperature we should get if the dynamo is operated under conditions as designed.

Whilst, therefore, the question of the melting point of the solder will be investigated further, we do not think this is the real cause of the trouble experienced, which we are still convinced is due either to an open-circuit on the electrical system or to the regulator permitting the dynamo to generate an excess amount of current.

BY/SB.{Mr Bull/Mr Bannister}
  
  


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