# Parking lot sweeper conversion.



## major (Apr 4, 2008)

Dakota said:


> ........ Is there a way to run a motor under load to determine the power sizing requirements? My load requirements are basically fixed (not like a EV). Motor turns a fan, that's it other than speed changes. Sizing could be determined under full speed and load.


Interesting application. For starters, please list your current power source specifications and reasons for wanting to electrify. A photo or two would help also. Welcome aboard.


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## Dakota (Jul 19, 2014)

major said:


> Interesting application. For starters, please list your current power source specifications and reasons for wanting to electrify. A photo or two would help also. Welcome aboard.


Hello Major, thanks for the reply.

The photos I'm going to try to attach is one of my units with a Kubota DF752 engine. The engine has a max intermittent 23hp and continuous of 18hp both at 3600rpm. At 2000rpm the continuous HP and intermittent is between 12-15hp. Torque values max of 32 ft.lb for continuous and 40 ft.lb intermittent this is at 2400rpms and drops with increased rpm. The engine turns 2 fans/blowers. One is around 22" and the other is 9". The small fan is belt driven from the front of engine and run continuously. In the future I will change this design and use a electromagnetic clutch so that it can be turned on and off from inside control panel. (same type clutch as on a lawn mower). The 22" blower fan is what does all the suction for the vacuum. It is 22" dia. and 8" deep.

I also use EFI Kohler Command engines. Peak 26hp(19.4kW) and 40ft.lbs torque.

I have a few reasons for exploring the use of a electric motor. 

Obviously with electric I wouldn't have the cost of fuel, oil change, and air filters. I COULD just use a hydraulic drive but oil tanks, supply lines, return lines and every thing associated with hydraulics makes things a little harder to design. There is still oil changes recommended at 500hrs first change and 2000hrs. second change. I would imagine the dependability of hydraulic would be good. I've also been very successful with the dependability of the IC engines...I've had one since 1996 and the hour meter broke at 14000 hrs a few years ago. (Kohler K582) I did install rings in this engine once. So I would need to compare this to a electric drive.

The second reason is sound levels. We all know that IC engines can produce a high level of noise. The blower fan also produces noise, but I can minimize this with design and noise deadening materials. I am finding it more difficult to work in some areas due to noise ordinances.

I would also like to help the environment.

Thanks again.


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## major (Apr 4, 2008)

Hi Dak,

Thanks for the additional info. I'll make some assumptions and use numbers I feel are in the ball park for demonstration of electric calculations. Hopefully this will give you a feeling for what you're looking at to electrify the sweeper/vacuum system.

Duty cycle = 4 hrs/day * 5 days/wk * 50 wk/yr = 250 cycles/yr.

Power = 20kW; so Energy = 80kWh for 4 hr cycle.

An 80kWh battery is about the size of the Tesla Model S battery. For a cheap one, maybe $30K. Possibly 2 to 3 times that figure to get one capable of 3000 cycles, installed, with charger. Let's assume this is not an option.

Power = 20kW. At 12V, that would be 1666 Amperes. This is not an option. At 100V, you'd need about 200A. So a motor/controller package like the HPEVS AC-50 at 96V would be a possible choice for power. Those run about $3500 I think. 

For the power source, instead of a battery, you could use a generator driven by the truck's engine. And that generator could be a AC-50 in generation mode. So another $3500. There would be a requirement for a small battery or converter to get the system operational, so figure a couple thousand more for that.

Those are my thoughts. Hope that helps.

major


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## Dakota (Jul 19, 2014)

major said:


> Hi Dak,
> 
> Thanks for the additional info. I'll make some assumptions and use numbers I feel are in the ball park for demonstration of electric calculations. Hopefully this will give you a feeling for what you're looking at to electrify the sweeper/vacuum system.
> 
> ...


Hello again Major and thanks for your input. I am right now looking at the specs on the AC50 motor. It says up to 71HP and 120ft.lbs of torque. I believe that to be a little over-kill for my application. I do think I remember reading that these are made in the USA which I like. 

Am I correct to say that the AC50 is a induction motor? Wouldn't a water cooled PMAC be more efficient and have a smaller footprint and also could be used as a generator? 

If I were to use a Motenergy ME1302 or ME1304 type motor, what would the power requirements look like. Also, I don't believe I could use the same math that is used for a EV since my blower is a set load (no hills or weight changes as in a EV). How dependable is the Motenergy motor?

Awhile back I placed this same project on a different site (electrical site). The folks on that site talked me out of electric and said go with hydraulic. When I saw the water cooled PMAC I decided to revisit the idea as I like the idea of water cooled and completely sealed. I was also thinking the efficiency of the PM may change things and allow me to use a smaller power generation system.


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## major (Apr 4, 2008)

I assumed when doing a large parking lot, the machine would need to run an hour or longer at load. That requires a continuous rating which I assumed to be 20kW from the source or about 20hp to the load. That 71hp figure was a peak or something. The continuous rating of the AC-50 at or near 3000 RPM is 20hp output. That is what you said you engine was doing. On a continuous load like that, power is power regardless if engine, motor or hydraulic.

Regarding the PMAC; I doubt it is more efficient than the AC-50 at load and likely a lot less durable. You want this this to last like 10 years, right? Induction motors are workhorses proven to go the distance. You might be able to find a liquid cooled PMAC to do the job but it isn't going to be from Motenergy. Look at industrial suppliers.


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## nimblemotors (Oct 1, 2010)

I would consider using the big serial DC motor the ME1002.
Why water cooling so important?
With no need for a real speed control and a pretty fixed load,
you might be able to just feed it a fixed voltage via the batteries with an slow-start on/off switch. Cheap, easy, reliable. 
Just the batteries will be expensive, as usual.


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## Dakota (Jul 19, 2014)

major said:


> I assumed when doing a large parking lot, the machine would need to run an hour or longer at load. That requires a continuous rating which I assumed to be 20kW from the source or about 20hp to the load. That 71hp figure was a peak or something. The continuous rating of the AC-50 at or near 3000 RPM is 20hp output. That is what you said you engine was doing. On a continuous load like that, power is power regardless if engine, motor or hydraulic.
> 
> Regarding the PMAC; I doubt it is more efficient than the AC-50 at load and likely a lot less durable. You want this this to last like 10 years, right? Induction motors are workhorses proven to go the distance. You might be able to find a liquid cooled PMAC to do the job but it isn't going to be from Motenergy. Look at industrial suppliers.


Thanks major, you just gave me a huge amount to think about...and regarding the Motenergy, that's what I feared. Let me do some more research into the AC-50 and I will probably have more questions if you would be kind enough to answer. I take it you have used the AC-50 or one of it's brothers. Huge thanks.


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## Dakota (Jul 19, 2014)

nimblemotors said:


> I would consider using the big serial DC motor the ME1002.
> Why water cooling so important?
> With no need for a real speed control and a pretty fixed load,
> you might be able to just feed it a fixed voltage via the batteries with an slow-start on/off switch. Cheap, easy, reliable.
> Just the batteries will be expensive, as usual.


I liked the idea of water cool because there tends to be dirt and grease build up on everything on a parking lot sweeper. So just imagine a thick layer of dirt insulating the motor and keeping the heat in. So I would imagine as long as the radiator on a water cooled is kept clean, then the motor would run cool. I would also think a cool motor would be more efficient??? I wonder if the efficiencies charts that some motor manufactures show are accurate?

I actually would like a speed control, or just 3 buttons to select slow, medium, and fast. No reason to use more power than needed.

I have the front IC engine to charge the batteries and assist in running the motor. So would I need a huge battery pack? 

I'll take a look at the ME1002. I'm not a dumb guy but this is all new to me, that's why I have so many questions. Thanks for the help.


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