MV brainstorm -- run golf cart motor on 110 AC?

[Elliot]

As some of you know – but most don’t – I’m motorizing a Grand Piano. Building a sturdy chassis is no problem, but the type of power is still to be determined.

I’ve read enough here to know that a gasoline engine will serve much better than electric batteries. So I should be looking for a motorcycle engine.

But I happen to have an electric golf cart motor-and-axle assembly. And I have two Honda EU-series generators to choose from – a 1000 and a 3000. So I’m thinking hybrid drivetrain, like a railroad locomotive. After all, I could use an EU on there anyway, for lights, and my fog machine.

The electric motor is a series-type DC motor marked for 36 Volts.

The golf cart was probably designed for a top speed of something like 15 MPH, so I expect to install a 3:1 chain reduction at the wheels.

I have no motor-controller. I’m thinking I can build a crude electro-mechanical one with a bunch of (trusty old multi-purpose!) Ford starter relays.
I do have a charger that will turn 110 V AC into 36 V DC, and I have several 12 V deep cycle batteries. So I could run Honda-charger-batteries-motor – plus a controller arrangement in there somehow.

But what about eliminating the charger and the batteries? I’ve read up a bit on electric motors, and I see that a SERIES DC motor will also run just fine on AC. I even understand how that works. The question is the voltage.

Since I need to come up with some sort of controller anyway… could I simply use a big variable resistance to “throttleâ€

[phil]

I'v never understood why diesel-electrics are so efficient, but they obviously are -- submarines and locomotives are all diesel electric (well, scept for the nukes). Running your electric motors directly off a gas-powered generator makes sense if diesel works, it seems to me.

Excellent thinking, whether it works out or not.

[motskyroonmatick]

I was going to write a post about the KISS method. (keep it simple stupid)

To hell with that. I want to see what you come up with.

My retired mutant vehicle is powered by a 750 V twin motorcycle engine and at an idle it goes 5 mph with 5,000lbs+ GVW. The chain drive makes allot of noise so that is something to consider. Belt drive would be much quieter.

[Elliot]

Yeah, like I said, guys... it's just a brainstorm, in case somebody can say "well, heck, just get a ten-dollar such-and-such pot from a such-and-such common washing machine and you'll be all set".

The simplest would probably be an ATV engine with a centrifugal clutch.

I have good experience with chain drives, and I don't expect we'll be playing the piano while driving. But sure, cog belts are nice.

[Token]

I remember tearing into my EU1000i a long time ago...

If memory serves me correctly, the Honda inverters are running a two phase system for AC output.

Unlike domestic power with the polarized plugs, one line, one neutral one ground, the EU1000i (I did not look at the 2k or 3k) has two lines and a ground, with each line running a 1/2 nominal voltage, 180 degrees out of phase. The "out of phase" part was a deduction since all I had is a multimeter and no oscilloscope to verify this.

The net line to line voltage is 110V AC, but the line to ground is ~ 55V AC.

Might be worth while to to poke a multimeter in the receptacle and confirm this was not some tech dream I had on the Playa.

Would be even better to plug a scope in and confirm the "out of phase" bit.

If my conjecture is indeed true, you could build dual 36V DC ports by inserting a rectifier from ground to each line and then buffering with a capacitor and battery.

20A 200V rectifiers are ~ $10 each. Add a capacitor from an old AC unit or similar ... Ta-Da!

55V AC has an RMS of ~ 38.8V, which should give you ~ 36V DC when rectified and filtered.

Where is the Captain. He has forgotten more about Honda EUs than mortals need know.

[Zhust]

[quote="Elliot"]Since I need to come up with some sort of controller anyway… could I simply use a big variable resistance to “throttleâ€

[dragonfly Jafe]

or you could just use a variac transformer, like this;

http://www.variac.com/staco_3PN10_20.htm

(and I have one you could play with if you give it back some day)

[unjonharley]

Of all my electric scoots (6 total)(12,24&36 volt) None can be charged while operating.

Some have warnings others have cut outs while charging..

Damaged one of the 12v when I hit the go switch while it was charging..

DC is hot so put a harrness on the wires.. Factory bundels melt down to one hell of a mess.. Makes me say grumpy words..

[Captain Goddammit]

If I were powering a grand piano for playa travel (and I absolutely love that you're doing that!) and wanted to do the whole thing as cheaply as possible, and have electricity available for lights etc. I think I'd skip the hybrid stuff. Too much BS to worry about. I'd probably start looking for a super-cheap or free rusty riding lawnmower to rob the motor and drivetrain bits from. I wish we lived close, I'd give you the only one I have left that didn't get turned into a mutant vehicle.
Then, I'd hit the junkyard for a $10 (that's what I pay around here at Pull-A-Part) GM "CS130" alternator, from late '80s to early '90s GM cars. Junkyards are full of those. Those alts put out lots of current at idle speeds, unlike almost all others. Use a car battery and cheap inverter.

The two MVs I did from riding mower drivetrains (the Playa Flya "airplane" and the tow truck for bicycles) each cost almost zero dollars, mostly just a bunch of welding and scrounging.

I started out using a Honda EU1000 on my Land Yacht, but on a mutant vehicle I found I had a lot of trouble keeping it running due to the constant dust being kicked up around a vehicle and have since gone to multiple alternators + inverter, which is working out a lot better for the playa.

If you use a gas engine of any kind, set up a remote air intake with PVC pipe, flex tubing, anything at all, with some sort of extra filter and an intake point located in the cleanest-air location you can.
Down-est side, it's loud, sounds like a lawnmower... which was perfect on the airplane... might suck for a playa-piano.

[SnowBlind]

If you look at the max output of your generator, the 1000 can source about 8 amps and the 3000 about 25 amps. Stepped down to 36 volts, that's 300 watts and 900 watts respectively. Alternatively, 0.4 horsepower and 1.2 horsepower. If you had the full 1000 watts available, that's 1.3 horsepower and 4 horsepower for the 3000.

That math is off. 8 amps at 110 volts is not the same as 8 amps at 36 volts. If you step it down, you get more amps. It's the watts the stay the same.

Ignoring conversion losses that means that your 8amps @ 110 volts would be 24 amps @36 volts, the 25 amps @ 110 volts give you about 76. That means it's 880 watts and 2750 watts, respectively.

[Captain Goddammit]

I think Snowblind is right, I was gonna say something too but I don't even think it's a great idea to do a gas generator/electric hybrid build on this thing anyway.

[gyre]

I think it might work out.
Remember that torque is likely three times horsepower.
Those golf carts are typically geared way down for loads to start with.

A curtis controller can be found cheap enough for one.

[theCryptofishist]

Of all my electric scoots (6 total)(12,24&36 volt) None can be charged while operating.

Some have warnings others have cut outs while charging..

Damaged one of the 12v when I hit the go switch while it was charging..

At a guess, I'd say this is standard with scooters and on wheelchairs. Mine won't turn on when the power cord is plugged into its little port on the joystick. The batteries are getting old so I've been resigned to an hour or two of inmobility every day sitting at my desk working on projects that don't involve movement beyond body in chair. Not optimal. Better than frying the motor, I suppose, but not optimal.

[Elorrum]

I actually waited a day before posting this bad pun. The perfect name for your driver: Van Playaburn.

[Elliot]

I actually waited a day before posting this bad pun. The perfect name for your driver: Van Playaburn.

Good 'un! So we have to hold a playing contest?

[Zhust]

If you look at the max output of your generator, the 1000 can source about 8 amps and the 3000 about 25 amps. Stepped down to 36 volts, that's 300 watts and 900 watts respectively.

That math is off. 8 amps at 110 volts is not the same as 8 amps at 36 volts. If you step it down, you get more amps. It's the watts the stay the same.

The amperage is the same if you just use a resistor which is the option I'm talking about. A switching supply capable of 3000 watts is well over $400. A transformer won't work because it's a "modified sine" inverter (at that power level, you absolutely need an inverter that outputs something much closer to a true sine wave; at small loads you get away with it because although the transformer's efficiency drops dramatically, it still works good enough.)

[Zhust]

or you could just use a variac transformer, like this;

http://www.variac.com/staco_3PN10_20.htm

(and I have one you could play with if you give it back some day)

Ya can't because of the modified sine inverter problem I mentioned above. My guess would be to derate by at least 50%, so the 22 amp model would be barely good for 10 amps.

[dragonfly Jafe]

or you could just use a variac transformer, like this;

http://www.variac.com/staco_3PN10_20.htm

(and I have one you could play with if you give it back some day)

Ya can't because of the modified sine inverter problem I mentioned above. My guess would be to derate by at least 50%, so the 22 amp model would be barely good for 10 amps.

good to know - I use mine for a "hot wire" foam cutting rig, 20-30v max (and I can't imagine a wire caring too much about sine waves!)

[SnowBlind]

If you look at the max output of your generator, the 1000 can source about 8 amps and the 3000 about 25 amps. Stepped down to 36 volts, that's 300 watts and 900 watts respectively.

That math is off. 8 amps at 110 volts is not the same as 8 amps at 36 volts. If you step it down, you get more amps. It's the watts the stay the same.

The amperage is the same if you just use a resistor which is the option I'm talking about.

Thats true, in that case the math is correct. However, thats quite a resistor you are talking about there. It would have to safely dissipate 600 Watts for the EU1000 or 1850 for the EU3000. Thats quite the space heater.

Also, besides the fact that it's horribly inefficient, it would only work if the load is pretty constant. Otherwise the voltage could vary quite a bit.

A transformer won't work because it's a "modified sine" inverter

As far as I know the Honda EU series doesn't use a modified sine wave inverter, but actually generates a good sine wave. What you are saying is true for most other generators though.

[TomServo]

I know its not a pipe organ, but can you play tocatta and fugue in D minor? LOVE that piece! Woke up to it, my first morning at burning man.

[Elliot]

Sure appreciate all the input, guys!

I definitely do not want to run a "space heater", so my resistor idea is a non-starter.

As I suspected (and mentioned) to begin with, I'm probably much better off with a plain gasoline engine. But I wanted to explore the series-hybrid idea, and you helped me do that. Thanks!

A gasoline lawn tractor/mower would be a good starting point, yes.

And no, I cannot play at all. I'm just providing a couple of pianos for others to play. Piano players tend to be such wimps about hauling pianos on the roof of their Civics and Corollas.

[plumblove]

I love your enthusiasm with this. The Playa is cruel. Keep it simple. And be careful with centrifugal clutches. They can be a problem is there's too much weight.

BTW a diesel/electric hybrid works well for subs and locomotive because electric motors do not need gearboxes. Could you imagine shifting a locomotive? Probably have to double clutch it. Ha! If semi truck has 16 speeds. How many would a train have?

[Elliot]

Heh, heh! I have a couple million miles in 18-wheelers, so I do know about gears!

Then there are my pedal vehicles, such as the one in my avatar. Even those benefit from two or three gears to choose from on the Playa, mostly depending on the wind.

I was moving the Baby Grand the other day, inside the garage, and the legs broke. Not as loud as I had hoped, but.... Now I definitely HAVE TO build a steel chassis under it!

[TomServo]

:D
Heh, heh! I have a couple million miles in 18-wheelers, so I do know about gears!

Then there are my pedal vehicles, such as the one in my avatar. Even those benefit from two or three gears to choose from on the Playa, mostly depending on the wind.

I was moving the Baby Grand the other day, inside the garage, and the legs broke. Not as loud as I had hoped, but.... Now I definitely HAVE TO build a steel chassis under it! :lol:

Just passed 750,000 miles. Would suggest hydraulic motors, if you were a millionaire...and put tank tracks on your vehicle. Can't wait to see the final result on the playa.

[Captain Goddammit]

GEARS!!!! Hey Elliot.... maybe that's it!
You're not an electric-vehicle nut who has controllers and stuff lying around to work with, but you ARE a mechanical geen-yus that could probably engineer a continuously variable transmission, or something close enough with a clutch and plenty of gears so that you could just run an electric motor at a constant speed, with nothing but an on-off solenoid. Don't even try to control the electric motor speed, just control the gearing. That kind of thing is right up your alley.

Get several batteries and the biggest most powerful battery charger you can. Your run-time would probably be perfectly fine, because when cruising the playa you rarely run continuously, you stop and start a lot. The duty cycle of your drivetrain is actually pretty small, but it can be charging whenever the Honda is on. And if you do carry the Honda, you can get as wild as you want with lighting without having to worry about efficiency - cuz more efficient lighting nearly always translates to more expensive, for the same output.


Oh yeah, and I don't know what the number total is but I've got shitloads of miles at the helm of Kenworth, Freightliner, and Peterbilt trucks myself!

[Token]

Flywheel and gears?

[Captain Goddammit]

So to be clear, what I'm suggesting is to run the electric motor on 12VDC with batteries just as original and keep 'em charged with the Honda.
On further thought - if you can get your hands on more than one big charger, you could put in battery cut-off switches (prolly should anyway) and separate batteries to charge on different chargers when you aren't driving for quicker recharge times.

Another thought, if controlling the MV with just a clutch and gearing ends up not smooth enough or too much pain-in-ass, you might even add in a car starter motor as a low-speed stage, then clutch it out and kick in the big motor when you're rolling.

[Elliot]

Oh Dawg; just what we need -- another diesel-dummy truck driver.

You are correct, Captain, I would like to get away with simply switching the el-motor on and off with a five-dollar Ford starter relay. And the problem is the sudden lurch at the start, which could be "geared out" of it.

So far as I know, continuously variable transmissions rely on friction to transfer the power. I once owned a DAF automobile with V belts on variable diameter pulleys. And I currently use NuVinci hub-transmissions in a KSR vehicle.

I have seen a hand-built prototype of a variable transmission using chains and sprockets. The inventor was a retired tool-and-die machinist. The thing was a work of art to behold. But it relied on numerous small sprockets that continuously engaged and disangaged the chain. The problem, as I see it, was that once in a while the tip of a tooth would hit exactly on a roller of the chain, and there would be a hickup in the function. That was its Achilles Heel. But it was the closest I've seen yet to a low-friction CVT.

As you may know, I spend more time on Kinetic Sculpture Racing than on Burning Man. In KSR, we need as much as 2000% (two thousand percent) range in our gearing. Automobiles and bicycles have only around 300% spread. So I'm already in pursuit of such an ultra-wide-ratio transmission. (Most racers use several bicycle derailers in series, but they break a lot of chains.)
Recently, I have come up with a shifting system that may be my "holy grail" transmission. But it is still at the rough mockup stage.

If I perfect this, a variation of it might serve with electric power on the Playa. Two gears might be enough. Start in a "Granny" gear and let that wind out, then pop it into "High Range".

Also, the chain could have a spring-loaded tensioner ON THE PULL SIDE, to take some of the shock out.

But I just watched a perfectly good three-year-old 17 HP lawn tractor sell for $400,- on eBay, and I'm thinking that would be a better way to go -- just as you have pointed out before, so you may be pretty smart for a truck driver.

[gyre]

You will still need a controller for the electric motor, if you use it.

[Elliot]

We are posting on top of each other here!

Two motors with very different gearing.... We do that in KSR. (Keep in mind, KSR is pedal powered.) In KSR, one of the hardest parts is getting out of the water. (Look at my avatar, if you are new to this.) I've had good luck with four people on a vehicle, with the two in the rear doing most of the pedaling in the water (with the rear wheels connected to a paddle wheel at the stern). Then, when the front wheels hit the shore, the front riders, who drive the front wheels, take over, rested and ready, with super low gearing to pull us up the slope to dry land.