OwnerPaul Nilssen
Owner's Other EVElectric Mower Mark ll
LocationPenguin, Tasmania Australia map
Email email image
Vehicle Ransomes
Self propelled lawnmower
MotorLucas Separately Excited DC
Originally a car starter motor. I rewound the field and now have a two speed motor.
DrivetrainSeperately excited DC and chain reduction
Switch and relay for two speeds and switch and solenoid for armature current
Batteries1, 12.00 Volt, Lead-Acid, Flooded
Second hand from a diesel Hilux
System Voltage12 Volts
Home brew
DC/DC Converter
Top SpeedLow speed is too fast and fast is dangerous.
RangeGood for a very small flat lawn
TiresSteel drum drive
Conversion TimeA couple of months after work and weekends
Conversion CostMower (rescued from the tip) $0
Motor $20
Bits and pieces from my shed and 'donated' from work. $30
Total = Not much.
The original series DC motor configuration was way too fast. I cobbled together a 100A PWM controller, but this just slowed the acceleration not top speed.
This led me to rewinding the field coils. Now the motor runs only a little too fast on slow speed (with field current) and way too fast on high speed (without field current). PWM controller is no longer used.

The starting circuit includes a switch to control an automotive starter-motor solenoid for armature current. On or off.

With a bit of sideways thought and a few skills, a scrapheap mower has been turned into a (nearly) useful electric device. Minimal cost and heaps of fun!

code by jerry