Control for automotive starter

E

ebetancourt

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Ernie
I am building an airplane mover. Until I’m satisfied with the design I want to use an automotive starter. Eventually the plan is a golf cart motor and controller. Looking for ideas on where to find a suitable 12V controller, fwd, rev and speed.
 
I really doubt very much that you want to use a starter motor. Take a look at the current draw...

Personally, I’d look at mobility scooters or power chairs. They’re dirt cheap or free, and designed for moving heavy objects at low, variable speeds, both forward and in reverse.
 
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Me? I'd look at a tarp motor with a low gear ratio. I'd use that as the starting point to build something like this:

http://www.aero-tow.com/E200.html

I would use the tarp motor to drive a chain drive where I could swap out the sprockets to adjust the speed of the unit to something appropriate.
 
I agree that a starter motor would probably be be a bad choice. Check out surpluscenter.com . They have lots of dc motors, gearboxes, and electronics to make a project like that work.
 
Speed control for a starter motor will be expensive due to the high current demand.
Electro-Mechanical relay(s) would work for forward / reverse/ stop.
 
As others have pointed out a starter is a bad choice. They're designed for very high torque for a very short time and will quickly overheat if used for more than 10 seconds or so. If you really wanted to run one in reverse you'd simply need four starter solenoids, wired in the style of an "x" wired DPDT reversing switch.

But there are many better motors out there for what you're trying to do.
 
Dana said:
As others have pointed out a starter is a bad choice. They're designed for very high torque for a very short time and will quickly overheat if used for more than 10 seconds or so. If you really wanted to run one in reverse you'd simply need four starter solenoids, wired in the style of an "x" wired DPDT reversing switch.

But there are many better motors out there for what you're trying to do.
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Reversing the current through a starter won't reverse the starter unless it's a permanent-magnet type. Reversing the current reverses both the armature and the field so that the rotation stays the same. One has to reverse just the field or just the armature brush connections, not both.
 
Several great suggestions, thanks. I don’t know what a tarp motor is but I’ll search. I have a gas PowerTow and an electric tow powered by a Milwaukee 20V drill. Both work well on airplanes with Scott tail wheels, but I’m trying to move a Waco YMF without the hassle of a Brackett tow bar.

Edit: Tarp motor would work, but I’m going to look for a mobility scooter first.
 
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My mobility cart tug. Works great, going on over 3 years. Bought at a flea market for $40 and did some minor re-re-wiring,
 
Dan Thomas said:
Reversing the current through a starter won't reverse the starter
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That. Had a positive ground car that had the battery connected as negative ground. Worked just fine (generator, not alternator, no radio). And worked fine after I fixed the battery connections.
 
I'm liking the tarp motor more, but looking for a speed control. I've found a speed control for brush but not brushless motors. Amazon has the motor and reversing control, everything else is from a go kart site. Need a speed controller though.
 
Those tarp motors should be brushed motors.
 
I had looked at used mobility scooters on the internet. Kinda pricey. Then I looked at Amazon - amazing! There are scooters that can move 300 pounds up a 15* incline for under $1,000. Surely that will push/pull a 2,100# airplane on a level concrete surface.
As soon as I get my tailwheel lifter finished I'll order one. My MIG Christmas present should speed that up.
 
A Denso or other type of reduction gear starter shouldn't draw all that much. Find one at a pick `n pull for $10 and give it a try.
 
ebetancourt said:
I had looked at used mobility scooters on the internet. Kinda pricey. Then I looked at Amazon - amazing! There are scooters that can move 300 pounds up a 15* incline for under $1,000. Surely that will push/pull a 2,100# airplane on a level concrete surface.
As soon as I get my tailwheel lifter finished I'll order one. My MIG Christmas present should speed that up.
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check your local Craigslist, or talk to assisted living facilities. You can hardly give away used ones. Seriously, the price of a lightly used power chair or scooter approaches “just come get it out of here”.
 
ebetancourt said:
I've found a speed control for brush but not brushless motors.
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Brushless motor speed control is far more complex and must be designed for the specific motor. For a brush motor it can be as simple as several resistors switched in series with the motor as seen in most automobile HVAC blowers.
 
flyingbrit said:
Brushless motor speed control is far more complex and must be designed for the specific motor. For a brush motor it can be as simple as several resistors switched in series with the motor as seen in most automobile HVAC blowers.
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Not with the amperages involved. A car's heater blower draws maybe three or four amps; anything powerful enough to push an airplane will draw more than 30 and maybe up to 100. A starter can draw several hundreds of amps. Resistors for high amperages are huge and get really hot. By the time one finishes fooling around he could have the brushless with a controller. The guts of a scooter could do it.
 
The commercially marked tug I looked at last week only had forward, stop, and reverse. It moved slow enough that speed control didn't seem to be necessary.

For those who wondered, a tarp motor is a (typically) 12V motor that includes a gearbox and is used to move the mechanized arms and tarp over an open topped dump truck or a semi with an open top trailer for carrying debris. The gearbox is usually somewhere between 50:1 and 90:1, meaning it delivers a lot of torque, which is good in our application. The tug I looked at powered the motor with two 12v batteries. A battery charger was integrated into the tug.
 
I am working at finishing the piece of my future mover that lifts the tailwheel. Once I get that done I plan to use a (very) modified scooter to power it. Seems like the easiest place to get everything I need in one place.
 
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