Renown Repulse Restoration Group has placed an order with a noted locomotive electronics expert for testing of a CU1 main control units and the rebuild of KV10 load regulators using modern components. The CU1 acts as the "central brain" of a Class 50, receiving and sending signals from and to all the other electronic control units in the locomotive. There are two KV10 load regulators in a Class 50, one is denoted CU3 and controls the main generator output. The other is denoted CU6 and controls the ETH generator. A KV10 is transformed into a CU3 or a CU6 by means of pairing with a control card CU3A or CU6A.
As with many electronic components of the Class 50, the KV10 design is full of obsolete components and with an eye to the future we feel this work is essential to our goal of "future proofing" 50029 and 50030 and ensuring them a long and secure future in preservation. The original design suffers from a tendency to "lock on", whereby faulty circuitry causes the CU3 to lock in the full position even if the power controller is at its minimum position. The only real solution is to repair the faulty circuitry but that repair knowledge gets ever more scarce with the passing of time. As a result, we feel that the decision to purchase four rebuilt units (one main and one ETH generator control unit for each of 50029 and 50030) is money well spent.
There are actually two sub-types of KV10, denoted B1 and B2 with slight differences in component types. RRRG has over twice as many B1s as we do B2s but our stock of CU3A and CU6A cards are only confirmed to work with B2 type KV10s. The rebuild process uses only the case, heat sink and thyristor from the original KV10 and as a result the control cards become obsolete as the components they contain are now integrated into the main unit. We intend to supply type B1 KV10s for the rebuild project with a decision on disposal of the type B2 units and control cards to be taken at a later date.
The following two shots show a rebuilt CU6-type KV10 installed in 50008 Thunderer. The first shot is taken from the Thin Man's side and the second is opposite the exhauster. Click on either to enlarge (opens in new window).
Needless to say, this work will not be cheap and we really need the support of the preservation community. Perhaps you could donate to our project, or become a member of RRRG and buy shares, or browse our online shop for items of interest? Your support is what has got us this far already and it is much appreciated.