electric motor conversion for a BCS or Gravely?

[cmyoung2]

I know this is about BCS, but.
I know this is for mostly rear tine tillers, but= I blew the motor on my old Ariens front tine, had an old 1 1/2 hp electric motor that used to be on a homemade air compressor, decided to put the two together, just to see. The electric motor weighs about 75 lbs, a little heavy. used 2" tubing for a spacer to get the motor high enough and for the bolt holes. Used a 4" pully on the motor (what I had) Wired the motor to 110v, it could also run 220v, have a 100' #12 cord from a junked floor polisher, a lot of the small plant beds are close to an outlet. results-- this monster will dig. Does better than the 5 hp briggs that was there before. And the best thing, it is quiet. don't need ear plugs, can actually talk around it. Cranks without a pull, every time!! It is a little heavy, have to make it go forward. Using it with four sets of tines instead of the two pictured. Works good in small beds the BCS can't fit into.
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old post- search
e-tiller
cmyoung2
09-08-2010
will get to the pictures
I still have it, still use it, would be great in greenhouse, works well in my small(4x8') raised beds. Use the BCS in the big garden.

 

[PILOON]

You are probably within a 100 miles of my location.

LOL, I'm closer, Ste Adele, QC.
and B4 lived in Pierrefonds and flew fro Les Cedres.

 

[freedomlives]

The AC electric motor route would be more advantageous in Europe, where 3-phase to the house is fairly common. I could run a pretty big motor on our 400V 25A 3-phase. Dragging the cable around would be a bear though! :-D

 

[MossRoad]

...
Speaking of gas, we are burning gasoline at a higher rate than ever before thanks to the EPA adding ethanol. The addition of 10% Ethanol decreases mileage by about 5-10% depending on conditions. The only conclusion I can draw is that the Government's priorities are a little different than what they say they are.

Looking forward since this post... gasoline consumption in the U.S. appears to have peaked back on 2007 and dropped every year for the last 10 years or so.

 

[Reid in QC]

I like this question about wired vs battery and I've given it some thought so too bad for you, I'm sharing my thoughts.

I would think that a 2 wheel tractor converted to electric would work really well in a greenhouse situation. In that case there would be no need for battery packs, but rather a self-reeling cable spool to let out the electric cable, and reel it back in so that it was overhead and never in the way. Mounting it like the spray wands at a car wash would work as well.

I didn't even know about the history of AC motor-powered wired ag equipment when I started thinking about this but I'm pretty sure that the cost of copper makes it an exercise in futility nowadays, though the pics and info at Bungartz.nl linked by js5020 are fascinating.

For a quick check on feasibility let's presume that your farm, like mine, doesn't have access to 3-phase 600V but only single-phase 230VAC. My battery-powered system is currently able to deliver peak power of 7.2kW (24V x 300A peak current as limited by controller). I could push this all up to 12kW or more by rewiring my batteries in series and upgrading to 48V controller but I really don't think that'll prove necessary. 7.2kW is 9.6 mathematical HP but torque from DC motor is higher than similar HP gas engine. So let's say 7.2 kW is fine peak power output and we want to achieve that with batteries or AC supplied by cable.

With batteries we need batteries, charger, motor controller, fuses, contactor, etc but we only need about 50cm of pretty heavy cable due to low voltage. My primary power wiring is 2gauge and 4 gauge. We obviously need to find a suitable DC motor (or AC + inverter which is likely too expensive, heavy and complicated for battery system) but these motors aren't outrageously hard to find once you know where to look. I got real lucky and paid $70 for my motor but $700 buys a brand new one.

For AC you would need a suitable 7kW AC motor and means to deliver power and control the motor. My guess is that you'd want some degree of speed control which means a 3-phase motor controlled by a variable frequency drive mounted on the machine. Without the drive you'd only have ON and OFF and no soft-start or other suitable controls for safety or precision. I suppose you could use the original clutch and run the motor at full speed all the time but with no speed control at all it would likely be a frustrating and imprecise machine.

So with a 10HP 3-phase AC motor and VFD (drive) you would get plenty of control and power. Now you just need to deliver between 30 and 40A at 230VAC to your controller and motor. Presume that the greenhouse in question is 35' x 150' (we have one this size and one significantly larger) and imagine building an overhead cable carrier rig down the middle with a pivoting arm to allow side-to side travel. Total cable length is at least 185' but realistically it's likely to be 200' of cable from the panel all the way to the tool. And that cable is what gauge?.. I'm sorry to say that even allowing for 4% voltage drop we're still looking at buying 200ft of 6-gauge 3-conductor wire and it probably ought to be something robust and flexible - at least SJOOW or "cabtire" if not TEK but let's not talk about pricing that much TEK. 6 gauge 3C won't be cheap and we can safely assume, without any research, that it'll be more than $2.50 per linear ft if BrokenTrack found that 10ga SO cost that much. So let's optimistically say 3$ per lin ft and we're already at $600 of wire. Realistically it may be $1000+.

We still haven't gotten started on the cable suspension mechanism for 185ft of the wire (rough guess tells me another $600 is optimistic, having built a 100ft festoon for watering hose at almost $400 on the cheap) so let's say the total cost of setting up one GH for our AC-powered BCS is between $1000 and $2000 and that's just fixed infrastructure in the building. The motor and VFD for the BCS will cost another $500 to $1500 depending on our luck with second hand parts. My other greenhouse is 300' long so another $2000 to $4000 for that one. So if I can get the same power and performance from my battery-electric system under $6000 I'm ahead of the wired option and I can use it in the field whenever I feel like it. My best guess is that I'm going to finish up under $1000 for the battery-electric conversion so I think that's a clear winner over tethered AC.

And in case there's still any uncertainty here's my summary of the strikes against tethered AC power
- lots of money spent on copper supply cable
- similar lots of money spent on cable management track, swingarm, slack retratction spools, etc.
- both above expenses must be duplicated in any additional greenhouses where you might want to use the tool
- travel between powered sites is not powered for your 450lb tiller so hitch up the mule or fire up the tractor or truck
- 10hp 3-ph AC motor weighs 150+ lbs whereas DC equivalent is 60lbs
- no field use possible without massive additional investment
- questionable safety of extensive cable network at 230VAC on 40A breaker in a greenhouse where all sorts of things can happen to abrade cable insulation. Heck, it's a rototiller!

Enough already?

Ok, I'll stop.

And don't get me wrong. I kinda like the idea of an indoor tool being tethered to AC power but I just don't think it's workable or appropriate in this situation and it would easily be 3 times as expensive.

~ reid

 

[freedomlives]

Now I remember the AgroKruh (FarmCircle) that a guy in Slovakia came up with. A lot has been made about it in documentaries, among the permaculture types, etc. It is a neat idea-- a pylon and arm in the middle of the field like circular irrigation, and then electric motor powered implements that travel along a rail as the arm turns performing different operations. It is more or less automatic and avoids compacting the ground. I am not sure if the inventor is sitting on patents for it hoping to strike it big, or if the idea itself just isn't profitable in terms of return on investment versus a BCS or small tractor.
All the different operations: Agrokruh v ?innosti - YouTube
Hoeing the ground: AgroKruh - Ry?ovak - YouTube
removing crabgrass: AgroKruh + aktývne brány na vy?esavanie pyru a iných burín. - YouTube

You can google AgroKruh -- maybe there is something in English about it.

 

[Reid in QC]

Super cool all that AgroKruh / Farm-circle stuff on YouTube. I don't see it being appropriate beyond a certain scale but it's definitely a neat approach to delivering mechanical power for a variety of farming tasks and there are surely some lessons to be drawn from his work.

Anyone who builds his own reciprocating spader with AC motor and worm gear reducer gets pretty high points for inoovation!

Thanks for sharing!

 

[js5020]

Reid excellent work on your conversion! I just read through the posts and watched the ytube vids, looks like a sweet conversion.

 

[Reid in QC]

Reid excellent work on your conversion! I just read through the posts and watched the ytube vids, looks like a sweet conversion.

Thanks for the encouragement. I look forward to finishing it to safe and useful standard in the weeks to come and will post update when it's really ready to go.

~ reid

 

[buickanddeere]

I would only consider 240V power.