pacerfan

Another strange anomaly with the 1/2" motors is with the pole pieces. The Hornby Dublo ones were painted black, the later ones by Wrenn were unpainted. The magnets that seemed to start losing magnetism were in motors that had the later (unpainted) pole pieces. I tried swapping the magnets on two motors a Hornby Dublo and a Wrenn, then remagnetising them. The weakened magnet didn't lose it's strength in the motor with older pole pieces, but the other magnet after being swapped did. Could the pole pieces on later motors have been made from a different grade of metal and not retain their magnetism as well?

I already have a Ronald Dodd remagnetiser. It is an excellent piece of kit. However, I have found that some of the Hornby Dublo/Wrenn 1/2 Inch motor magnets lose some of their strength a few days after being remagnetised. I am wondering if the magnets are defective and are not retaining their full magnetism. (A fully magnetised 1/2" motor can be picked up by a small screwdriver by touching the top or bottom pole piece above the magnet poles). The Tri-ang X04 magnets seem to retain their full magnetism after being remagnetised. I was also wondering if these magnets coud be rejuvenated with a high voltage magnetiser using capacitors?

I have attached the schematic.

The earlier thread regarding this topic is here:- http://www.rmweb.co.uk/community/index.php?/topic/29096-revitalizing-wrenn-locos/ I have got a copy of the schematic for the original Meccano Magnetiser dated 1.9.54. I downloaded it a good few years ago. I cannot give the link to it as it is now defunct. There are no capacitors shown in the circuit diagram. The magnetiser coil consists of 2840 turns of 19 SWG wire. There are two time lags shown, a bridge rectifier, a rotary mains switch and a GEC high voltage push switch.