05-02-2019, 03:47 PM
I'd forgotten that back in the 1970s we'd arrived at Astle park traction engine rally in the rain erected our tent, new mum Sue was under the weather so I took our daughter in her buggy for a walk round. It wasn't long before I came across a crowd round a showman's engine which had no lights on, yes they'd got a battery to restore the dynamo field magnetism, and run it up with no joy. I asked about it's history to be told that the dynamo had recently been overhauled by Mather & Platt and hadn't been used since refitting to the engine. Now this dynamo had six leads going to the switchboard, two were the output from the brushgear, two were the series field and two were the shunt field. OK I said all you have to do is reverse one pair of field connections at the moment one field is opposing the other. All eyes turned to me then they switched one pair of leads and ran the engine up followed by a loud cheer as all the lights came on. So yes I have reversed the field connections but not on a Seven. Catherine in her buggy was in awe at the goings on with not a peep out of her.