Suitable motor for converting petrol garden tractor to electric

[woodman-46]

I need to buy an electric motor to convert a petrol ride on mower to a mini tractor/ride on. The existing engine is 12hp Briggs and Stratton . The mower deck and a lot of excess weight has been removed from the mower and it is much lighter.
I have seen an old DC shunt motor 180v 750w 4.9A continuous . It is the right size (not very big) to fit in the engine bay and rpm is only a little less than the original engine. Obviously this seems a high voltage and I wondered if it has to be powered by batteries of that voltage or can it be powered by less voltage ? Also I need the motor not to produce high speed but rather slower speed but more torque. Would this motor seem like a could bet?
Thanks in advance
James
PS I am aware of all the safety implications here and of course would have safety/ cut off switches installed. I just need to know about the motor power please.

 

[bernardgreen]

1 hp is 750 watts ( approx )
12 hp is 9,000 watt of 9 kW

So your electric motor is very under powered and shunt wound motors are difficult to control. They have a hazard that if the field winding fails or is disconnected when the rotor is powered and rotating the rotor can accelerate out off control.

As a project it would interesting and possibly dangerous.

To create a usable vehicle would be very difficult.

To purchase a 180 volt battery ( 15 batteries each 12 volt ) would cost a lot more than a ready to drive toy from HERE

 

[conny]

1 hp is 750 watts ( approx )
12 hp is 9,000 watt of 9 kW

So your electric motor is very under powered and shunt wound motors are difficult to control. They have a hazard that if the field winding fails or is disconnected when the rotor is powered and rotating the rotor can accelerate out off control.

As a project it would interesting and possibly dangerous.

To create a usable vehicle would be very difficult.

To purchase a 180 volt battery ( 15 batteries each 12 volt ) would cost a lot more than a ready to drive toy from HERE

Had the experience to see a 910Kw DC motor do just this one Saturday afternoon when the engineer didn't look at what he was turning down before doing it.
The test bed he should have used was in the next workshop so to save time he ran cables through to the repair shop. Went to increase the speed by altering the armature voltage but simply put his hand around the corner and 'felt' for the variac control knob. Turned the wrong one and realised when he stepped back in to the repair shop. Armature suddenly raced up to a very high speed and smoke came belching out. Another lad standing near the main incomer panel hit the E stop but wasn't quick enough to stop severe damage.

 

[woodman-46]

Thanks for your responses. The existing petrol engine revolves at 3000rpm and in operation is left at that permanently. The difference in speed is chosen by which gear is used. The engine power/pulley is disengaged from the gears by a clutch pedal that when pressed loosens the drive belt and therefore no power can reach the gearbox when this is done. As made clear I don't want to use 180v's worth of batteries that's why I wanted to know if 48v would be enough. Also not wanting to use another ride on toy thanks, that is not the point of this project.
Also whatever set up I end up using, as mentioned, will have an obvious cut of switch. My son uses our working lawnmower without problem and operates gears, clutch etc better than I do. This "tractor" would be used in a field and have a top speed of about 6mph using the gears. In the minute chance of a motor malfunctioning he would either press cut off button or press clutch . I made a small buggy for him using a golf buggy motor and all worked fine for over 5 years. Thanks anyway.

 

[flameport]

As was explained in the other thread, you can't just remove a petrol engine and shove an electric motor in it's place.

A motor designed for 180 volts will not work on 48 volts.

 

[EddieM]

I would ditch this idea immediately.

 

[conny]

I would ditch this idea immediately.

As was suggested in the other thread. If people choose to ignore good advice then there is nothing anyone can say to dissuade them from their course of action.

 

[EddieM]

As was suggested in the other thread. If people choose to ignore good advice then there is nothing anyone can say to dissuade them from their course of action.

Oh, ok.

 

[JohnW2]

... If people choose to ignore good advice then there is nothing anyone can say to dissuade them from their course of action.

Indeed - and, in this case, quite apart from potential dangers etc., I don't think that there is any way that the intended 'course of action' is going to result in any solution that 'works', anyway!

Kind Regards, John

 

[scbk]

Thanks for your responses. The existing petrol engine revolves at 3000rpm and in operation is left at that permanently. The difference in speed is chosen by which gear is used. The engine power/pulley is disengaged from the gears by a clutch pedal that when pressed loosens the drive belt and therefore no power can reach the gearbox when this is done. As made clear I don't want to use 180v's worth of batteries that's why I wanted to know if 48v would be enough. Also not wanting to use another ride on toy thanks, that is not the point of this project.
Also whatever set up I end up using, as mentioned, will have an obvious cut of switch. My son uses our working lawnmower without problem and operates gears, clutch etc better than I do. This "tractor" would be used in a field and have a top speed of about 6mph using the gears. In the minute chance of a motor malfunctioning he would either press cut off button or press clutch . I made a small buggy for him using a golf buggy motor and all worked fine for over 5 years. Thanks anyway.

You answered your own question there, just buy an old golf buggy

https://www.ebay.co.uk/itm/used-ele...514751?hash=item52389396bf:g:c0YAAOSwMghe74tq