101: Saturday 9th January 2010

There's one thing you can rely on with British weather, and that is that if you make plans that depend on good weather then it will be bad. As you can see from the photo, there is still snow and there is still more coming. I received an email from the alternative energy store to say that they are waiting to receive a replacement DLS 55 DC-DC converter from Iota and will email me again when they have it to arrange for the shipping. I am now looking into AC drives to see how much I can get a system up and running for. The big advantages with AC is the motors can run a lot faster with a constant torque across the range, there are no brushes on the motor and they lend themselves to regen braking. All this can improve the range of the batteries and allow a fixed ratio transmission like a simple differential for a single motor system so no transmission losses through a gearbox. This also simplifies the mechanical system and allows more space for batteries. There are some neat compact AC motors out there too. The disadvantages are that to get the high speed requires higher voltages and hence more batteries, although the current does not need to be so high with a higher voltage. Much higher power rated motors are available. The cost of AC system seems to be a lot higher, but I thought the same about DC until I started shopping around.