Hi Everyone
I am new to V is for Voltage but I have decided to take the plunge and perform my first conversion. I maybe starting to big but no guts no glory. I am planning on changing my extremely pollutant lawn tractor to electric and have seen some conversions online but instead of just placing an electric motor where the gas engine was I want to have an electric motor on the blades directly and one for the drivetrain. I think I have picked the one I need for the drivetrain but I am having difficulty finding the right motor for the blades, any suggestions?
I am planning to go with a 48 volt motor on the drivetrain and thinking this voltage would work best for the blades since it would reduce the electronics needed for different voltages off of 1 48 volt battery bank.
Any help would be appreciated.
Welcome to this site and welcome to trying to convert / upgrade to electric. I have an E-16 and an E20 I also have converted many lawnmowers to electric from gasoline.
You may get a lot more help from local clubs like EAA, or as I am in the north east I belong to NEEAA chapter. We convert anything to electric as mainly cars and trucks but do motorcycles and lawnmowers too. Then there is the EV tractor list out there too. On my GE tractors there is a shunt wound motor and works great on pure 36 or 48 volt DC or with a pulse width modulator like a 1205 Curtis. On mine the field current is limited to 2 amperes so use a resistor or low power PWM there to limit current if using 48 volts. There are so many choices for motors. There will be a meeting of green in New Haven CT this Saturday 11 +12 Sept 2009. I am sure there will be some tractor showing.Fell free to call me any time at 518-929-2018 Rusty
KB1UKU
Welcome! There are people on this forum who do conversions and conversions are certainly within the realm of discussion on this forum.
What kind of tractor? What kind of motor did you choose for the drive train? Does the tractor have separate controls for speed & blade speed? It's been a long time since I last rode a lawn tractor so maybe that was a naive question.
It of course makes perfect sense to use a 48 volt motors for each.
Another naive question is - do you need to vary blade speed or is a simple on-off enough?
My first thought on a motor suggestion is the etek or its modern equivalent the mars motor.
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Thanks for the input so far guys. To give a little more information. I am planning on having the blades run at one speed. Even though with the gas engine the speed of the blades could vary with engine speed it is not something I intend to do, simple on-off is perfect. The tractor is a simple Craftsman 17.5 hp, 42 inch deck, 2 blades, hydrostatic drive. My thought was to go with the PERM 080 motor connected right at the hydrostatic drive pulley and then separate motors for the blades. In other configuration it seems people just replace the gas engine with an electric (some used Etek) but my thought from an efficiency point of view is, it would be better to take the pulley and belt system out of the loop altogether and go direct, also each motor can be properly sized for the job. In looking at push mowers they are now rated in cc or gross torque so a 22 in push mower will have a gas engine with ~ 5 lb/ft of gross torque at ~3300 rpm. I am using those numbers as a starting point but maybe that is not a good way to look at it.
Thanks
Actually looking at the torque & RPM is exactly what you should be looking at.
The idea seems sound in that you would avoid an efficiency loss and complexity in the drive train.
If you haven't seen it, this book has an indepth discussion of power, RPM and torque.
http://www.7gen.com/affiliateproduct/electric-vehicle-books/24696-build-your-own-electric-vehicle
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki