Using a 24v Drill as a chain drive motor ?
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bigmoose
1 MW
For sprinting around with the right sprocket/drive ratio they will work. I have used them since 1999 as drive motors for wheeled "mobile sensor platforms" that came in around 80 pounds total. One or more have been equipped with temporary chairs in the past for demonstrations. In my archive I should have a picture or two of a US Congressman riding one at an event from the late 1990's. I used the old Bosch 12 volt drill systems. I have had exceptional luck with the gearboxes also.
The problem comes with high torque, low speed operation, they can't handle being "lugged" for long (1 minute or more) periods of time. This would be the same as saying they have a current limit under which to survive. I doubt they would make a 10 mile ride at 200 watts continuous. The motors don't have a great ability to shed heat. If I recall correctly, and I would have to dig out old notes, I "think" I set up the controllers to integral limit below 20 amps on the Bosch, but let it peak to 50/60 amps. Remember our duty cycle is sprint, wait and listen. Creep a bit, make a measurement, send video.... sprint, wait... It is not a continuous duty cycle. When we put a chair on the platform, people could run down a 12 Volt 35 AH lead acid with no problem playing around with no damage to the drive system.
The problem comes with high torque, low speed operation, they can't handle being "lugged" for long (1 minute or more) periods of time. This would be the same as saying they have a current limit under which to survive. I doubt they would make a 10 mile ride at 200 watts continuous. The motors don't have a great ability to shed heat. If I recall correctly, and I would have to dig out old notes, I "think" I set up the controllers to integral limit below 20 amps on the Bosch, but let it peak to 50/60 amps. Remember our duty cycle is sprint, wait and listen. Creep a bit, make a measurement, send video.... sprint, wait... It is not a continuous duty cycle. When we put a chair on the platform, people could run down a 12 Volt 35 AH lead acid with no problem playing around with no damage to the drive system.
John in CR
100 TW
The guys with the battle robots love them. Check out the Robot Marketplace for more info. http://www.robotmarketplace.com/products/dewalt_main.html My issue would be noise and worries about continuous duty. That was just an idea I threw out there for cheap, easy, and potential using a scrapped item for low speed hill climbing assist as an answer to the question you posed originally.
Another more readily found scrap motor is to take an alternator and turn it into a motor. Do a search in the motor tech and non-hubmotor sections for more details about how to do that.
Another more readily found scrap motor is to take an alternator and turn it into a motor. Do a search in the motor tech and non-hubmotor sections for more details about how to do that.
spinningmagnets
100 TW
I wouldn't buy a new drill or circular saw to do this with, but...
If you found one almost free, it wouldn't hurt to experiment. Once the batteries don't hold a charge anymore, most contractors seem to just pay a few dollars more to buy another combo kit including the tool, rather than just new batteries. So, the old tool can often be had very cheap, even though it still works fine.
DeWalt, Milwaukee, and others make 24V 28V and 36V tools. Somehow I have a suspicion that the circular saw would work better for this than the drill... (check EBAY?)
edit: Makita, Ridgid, Ryobi, Black & Decker, Craftsman, Porter-Cable, Kawasaki, Bosche, etc...
If you found one almost free, it wouldn't hurt to experiment. Once the batteries don't hold a charge anymore, most contractors seem to just pay a few dollars more to buy another combo kit including the tool, rather than just new batteries. So, the old tool can often be had very cheap, even though it still works fine.
DeWalt, Milwaukee, and others make 24V 28V and 36V tools. Somehow I have a suspicion that the circular saw would work better for this than the drill... (check EBAY?)
edit: Makita, Ridgid, Ryobi, Black & Decker, Craftsman, Porter-Cable, Kawasaki, Bosche, etc...
oldpiper
1 kW
As for getting something both new and cheap, remember it's getting close to Xmas, and tool manus/stores are going to be putting deals together. A few years ago, I got a Xmas special of an 18V drill (it was a high V drill for the time) + extra battery + charger/radio for $59 at one of the chain home improvement stores. Right next to it on the shelf was the exact same drill with only the extra battery for $125. And they say the retailers are running scared this year, so it might be even better for us.
Cameron
Cameron
spinningmagnets
100 TW
Just found on EBAY: http://cgi.ebay.com/Black-and-Decke...200?pt=LH_DefaultDomain_0&hash=item1e5fc36a90
Black and & Decker Cordless Circular Saw 4100 RPM 24V
Item condition: Manufacturer refurbished
Time left: 2d 01h (Nov 18, 201021:20:33 PST)
Bid history: 2 bids [Refresh bidhistory]
Current bid: US $1.25
EDIT: there were 8 bids and it sold for $22 + shipping
Black and & Decker Cordless Circular Saw 4100 RPM 24V
Item condition: Manufacturer refurbished
Time left: 2d 01h (Nov 18, 201021:20:33 PST)
Bid history: 2 bids [Refresh bidhistory]
Current bid: US $1.25
EDIT: there were 8 bids and it sold for $22 + shipping
spinningmagnets
100 TW
Drills and saws aren't really rated for continuous duty. You use them for a minute, and then set them down to cool off. I "think" this is why they can get away with most of them having brushed motors and controllers. I suggested the saw first because I believe most of them already have an internal gear-down with a bigger reduction than the reduction inside most drills.
Again, do NOT buy a new one to try this out with, but if you find a used one thats near free, it couldn't hurt to play with it.
Again, do NOT buy a new one to try this out with, but if you find a used one thats near free, it couldn't hurt to play with it.
sk8norcal
1 MW
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Samba
100 W
I used 12v dewalt drills for years. The nicad batteries were about $55 each, but you could get a drill, 2 batteries, charger, case for $120. So after 6 years I had like 4 drills, 3 good batteries, 5 dead batteries. I switched to 18v lithium and haven't needed new batteries yet - but for now there should be lots of extra drills around that were bought just because they basically came free when you bought 2 batteries.
My 18v has a 2 speed gearbox - 0-500/0-1700 and is 350 watts. There is a heavier version thats 3 speeds and 450 watts also 18v. Mine is 3 pounds without battery and a 1 pound battery thats 2.3AH. If I run it hard for more than 20 seconds (e.g. mixing paint) then the exhaust air gets quite hot. It has an adjustable clutch meant to keep screwheads from breaking off or being driven all the way thru a board. I'd bet you could use that clutch to limit it to a power level thats safe for very long running. It also has a reverse switch and a trigger lock so you can take your finger off the trigger but leave the drill running.
You have some fairly small wheels, though I forget just how large. You need to figure out how fast you want the wheel to turn - which depends on the wheel size and the speed you want.
RPM = (MPH * 336) / wheel_diameter_inches
210 rpm ~= (5mph * 336) / 8inch
The difference between the motors speed, and the desired wheel speed is the gear ratio you need.
If you want 210 rpm from a 500rpm motor then you need a wheel sprocket thats 500/210 times as large as the motor sprocket 2.38:1 .
If you use a 12 tooth sprocket at the drill, then the wheel sprocket would be about 29 tooth.
If you switch the drill to high gear, 1700 rpm, then the wheel will turn at 1700/238 = 714RPM which is 17mph on an 8 inch wheel. So maybe you want to look for a 3 speed drill that doesn't have such big difference between the speeds.
Anyway, those are the formulas you need but you need to calculate it for your wheel size, drill speeds and desired speed.
Expect the motor to turn a bit slower than the given speed when its doing real work. Maybe use a 400rpm in formulas when it says 500rpm(no load)
My 18v has a 2 speed gearbox - 0-500/0-1700 and is 350 watts. There is a heavier version thats 3 speeds and 450 watts also 18v. Mine is 3 pounds without battery and a 1 pound battery thats 2.3AH. If I run it hard for more than 20 seconds (e.g. mixing paint) then the exhaust air gets quite hot. It has an adjustable clutch meant to keep screwheads from breaking off or being driven all the way thru a board. I'd bet you could use that clutch to limit it to a power level thats safe for very long running. It also has a reverse switch and a trigger lock so you can take your finger off the trigger but leave the drill running.
You have some fairly small wheels, though I forget just how large. You need to figure out how fast you want the wheel to turn - which depends on the wheel size and the speed you want.
RPM = (MPH * 336) / wheel_diameter_inches
210 rpm ~= (5mph * 336) / 8inch
The difference between the motors speed, and the desired wheel speed is the gear ratio you need.
If you want 210 rpm from a 500rpm motor then you need a wheel sprocket thats 500/210 times as large as the motor sprocket 2.38:1 .
If you use a 12 tooth sprocket at the drill, then the wheel sprocket would be about 29 tooth.
If you switch the drill to high gear, 1700 rpm, then the wheel will turn at 1700/238 = 714RPM which is 17mph on an 8 inch wheel. So maybe you want to look for a 3 speed drill that doesn't have such big difference between the speeds.
Anyway, those are the formulas you need but you need to calculate it for your wheel size, drill speeds and desired speed.
Expect the motor to turn a bit slower than the given speed when its doing real work. Maybe use a 400rpm in formulas when it says 500rpm(no load)
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