Four blade fan?

[Howard Wright]

Hi All

Thanks for all the answers.  It seems it is a fairly common problem with older period cores.  Looking at the core there is much less transfer area for heat to dissipate than in a modern core.  I spent a happy hour yesterday poking a bottle brush through each hole and quite a lot of dust came out!

I did look at an electric fan but the power consumption (120Watt that’s 20Amps) of the 6Volt one that came up on a Google search seems very high and would strain the cabling if not the dynamo!

I might try a four blade fan (which might sap as much power as an electric fan but won’t strain the wiring or dynamo).  I’ll let you know how I get on.

Thanks again

Howard