[slawking]

Originally Posted by Dennis

Way back when I was just a beginning member here I helped out someone who wanted a conversion with a tractor to electric. He needed a controller and wiring diagram to build his tractor. So I gave him a free Alltrax AXE4834 and give him a wiring diagram that I drew up in MS paint. So I suppose you guys are also looking for a wiring diagram. So here it is:







This circuit simply performs the AND function for safety as follows: the key switch, foot switch, seat switch, and throttle pot box lever switch must all be ON or HIGH in order for the lawn mower's traction motor to be active. The Key switch also engages the Negative side contactor. The reason a negative side contactor is used is so an extra safe guard is in place in case one of the contactors has a catastrophic failure such as welded contacts which makes it permanently ON. Also this actives the pre-charge circuit when the switch is turned on to avoid sparks being present when the user hooks up battery terminals to the batteries if this contactor was not present. Sparks at the batteries is not such a great idea so it also serves to reduce explosion hazards.

There is a warning that anyone who uses this wiring diagram should adhere to and that is the THE CONTROLLER MUST HAVE THE HIGH PEDDLE BEFORE POWER UP LOCK OUT ENABLED. FAILURE TO ENABLE THIS FEATURE IN THE CONTROLLER CAN RESULT IN SERIOUS INJURY OR DEATH IN WHERE THE USER CAN HAVE ALL SAFETY SWITCHES ACTIVE EXCEPT THE KEY SWITCH WHICH THE USER MAY CUT THE KEY SWITCH TO THE "ON" POSITION RESULTING IN INSTANT TAKE OFF OF THE LAWN MOWER WITHOUT WARNING.

As useful as this diagram is (and it is very useful), for Riding Lawnmower Purposes using a PERMANENT MAGNET SERIES MOTOR, a Controller is NOT desirable. I bought and ALLTRAX controller and found it totally NON-DESIREABLE. This is because of two major factors, 1) It is an unnecessary added expense (~$400), and 2) MOST IMPORTANTLY it forces the blades to run at VARYING SPEED (throttle dependent) which is HIGHLY UNDESIRABLE when mowing the lawn. A constant blade velocity when mowing the lawn is HIGHLY DESIRABLE when mowing the lawn, and both everyday Gas push mowers and riding lawnmower bear witness.

I am in fact planning to use the ALLTRAX controller for other purposes (as a tractor for hauling, etc), so the above diagram IS USEFUL for those kinds of applications.

Regards

Bob

[Bentzon]

Doesnt most modern lawnmowers have a hydrostatic transmission for the movement.
So all you would need a controller for is motor protection and low/high voltage cutoff.

[slawking]

Originally Posted by Bentzon

Doesnt most modern lawnmowers have a hydrostatic transmission for the movement.
So all you would need a controller for is motor protection and low/high voltage cutoff.

My riding mower is an older double pulley belt design, these are still widely used today, and are some of the less expensive models out there. I would think that hydrostatic transmissions would still need to have a way to make sure that both the mower and blades move at a constant rate.

Do hydrostatic transmissions allow you to change gears?

If not, then a double contactor arrangement COULD be used in lieu of a controller for the HI/LOW voltage arrangement you suggest.

[Bentzon]

Its like a automatic gearbox with hydraulics instead of gears. They got belts from the motor to the hydrostatic transmission and to the blades. The blades are engaged by a magnetic clutch. So the input to the transmission and to the blades are locked by the pulleys. You can lower the rpm of the motor but it doesnt make much sense to do.

This is how its made on the one i got so my idea, if i ever get time to make it, was to just run a electric motor at full voltage for constant rpm all the time. Bolted to the original belt pulleys(where the ICE motor was) and let the OEM parts do the rest.
Probably not the most efficient solution but its pretty straight forward. I dont really see how you would run direct drive to both wheel and blades without getting poor cutting performance at low speeds. Expensive way to do it was to have one or two motors for the blades and one for the drive.

[Dennis]

As useful as this diagram is (and it is very useful), for Riding Lawnmower Purposes using a PERMANENT MAGNET SERIES MOTOR, a Controller is NOT desirable. I bought and ALLTRAX controller and found it totally NON-DESIREABLE. This is because of two major factors, 1) It is an unnecessary added expense (~$400), and 2) MOST IMPORTANTLY it forces the blades to run at VARYING SPEED (throttle dependent) which is HIGHLY UNDESIRABLE when mowing the lawn. A constant blade velocity when mowing the lawn is HIGHLY DESIRABLE when mowing the lawn, and both everyday Gas push mowers and riding lawnmower bear witness.

I am in fact planning to use the ALLTRAX controller for other purposes (as a tractor for hauling, etc), so the above diagram IS USEFUL for those kinds of applications.

Regards

Bob

Bob, the controller is only for the traction motor for speed control and current limit. Current limit is very important both to protect the motor from excessive current demand and to protect the batteries. If a large power resistor is cheaper then be all means build you a resistor based speed controller. It would be KISS design if you went that route, but do not expect it to be very efficient...

For the blades a better idea is to use separate electric motors connected to a type of "sacrifice" coupling that sheers keyways if the blades hit something hard so as not to damage the motors. Btw, there is no such thing as a PM series wound motor. A series wound motor has the armature circuit wired in series to the field circuit so it is always a 100% electromagnet type motor. If the motor uses permanent magnets for the field then it is a PM motor.

[slawking]

Thanks Dennis for the clarification of definition of series wound vs PM motors. I guess my point has less to do with the need for efficiency than for the need to maintain a constant mower speed and blade velocity. Adding a throttle to constantly adjust the motor RPM is not really conducive to that end (in my view).
As built, the mower runs for about 1 1/2 hour. In my part of the country the electricity used to recharge after that amount of time costs about the same as a pint of gasoline, so I guess it is efficient enough (for me at least). And its dead simple to maintain.

Regards,

Bob

[sjc]

Has anyone done a tractor conversion and used a power-takeoff (PTO)?

I'm looking at doing a conversion of a JD with a mower and snowblower. Is this any different than just driving the mower blades at constant speed?

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