170: Tuesday 3rd November 2010

Nightmare, it happened again! Another potentiometer bites the dust again. It is a good job I have a bag full of cheap pots in my garage, so I transplanted another of these small 10k pots onto the control box with my special brass shaft adapter. I have a feeling that the spring is causing these pots to break down as it is bending the shaft a bit when the throttle is planted. Also the microswitch for the throttle decide to come apart and the bits fell on the floor. I managed to find them all and re-assemble it. When I broke down I put into effect my contingency plan to insert a resistor into the connector for the pot, but in the process I accidentally pulled out some control wires. It took me a little while to notice this and in the process of doubting the correctness of my resistor connection, I pulled one of the pot wires out of the connector. I only had about 1 mile to go, so I fixed the wires in place as best as I could, then got the motor running after a fashion. Unfortunately I could not get enough power to get moving, so I set the creep speed up to maximum and used a back route down a side street that was very quiet and crept along the road. I went over a bump and suddenly I had some on/off acceleration just as I was about to rejoin the main road, cool. I jerked it home (it wasn't too bad in 3rd gear) and parked up. After fitting the cheap pot all is back to normal and the throttle response is smooth again. I know I have 2 heavy duty wire wound pots waiting to be picked up from the post office tomorrow, and I have now ordered a conductive plastic 1w pot as one of my colleagues suggested this might be a better choice. Wire wound pots seem to be useless. I am still looking out for a hall effect sensor that is suitable as well. Hopefully the conductive plastic pot will work out. If it starts getting rough then I will go for a hall effect rotary sensor.

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