It has five data/signal outputs from the controller to the motor in addition to three heavy duty power wires. Not sure exactly where the power wires come from since the stuff is encased a glob of glue. One of those signal wires is purple, the other four are black. Is that common? If so, what's it called so I can find some information about it. Be happy to supply more pictures if needed. Thanks.

Brushless motors often (but not always) have either hall sensors (three signals) or an encoder (two signals, sometimes differential pairs, sometimes with an extra "zero position" signal). These often need power (+5v/gnd), so three halls plus power = 5 wires makes sense. If you watch these signals with an oscilloscope, hall sensors would show a three-phase signal about 1x to 6x the RPMs of the motor (in sync with the power wires), while encoders would have two quadrature signals in the 500x to 4000x the RPMs range.

Is this common for a brushless motor controller?

Sep 02, 2015 25 Replies

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John Doe 10 years ago

amdx wrote in news:msd4es$cgb$ snipped-for-privacy@dont-email.me:

Efficiency is a top priority in cordless drill design. That's why the brushless versions are advertised as 57% more run time. Any cordless device that sucks current is designed to be efficient. Cordless drills certainly are.

Using my current electric bike (under)powered by a DeWalt DCD780... I traveled 8 1/2 miles using one 5AH battery and one 4AH battery with a small charge left.

There is no way to stress a DeWalt DCF899. Also, there is little risk of stressing the bicycle's bottom bracket, it too is a heavy duty part. So the connection can be sloppy without risk of damage. And the connection is simple as sticking a 12 point socket on the impact wrench to fit the square taper bottom bracket spindle.

I'm using a 20 inch wheel bike. Hopefully, the only werk will be securing the drill in position against the left side of the bottom bracket.

If only the impact wrench used gears instead of the controller for speed regulation!

Interestingly IMO... Motor torque output is easy to apply to a bicycle when driving the bottom bracket. Motor torque is measured in foot-pounds (a pressure rating, formerly understood as werk). It's the twisting force in pounds applied to the end of a 1 foot stick. So all you have to do is visualize putting weight on the bicycle crank as if pedaling a bicycle.

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krw 10 years ago

I don't believe that to be true. The top priorities are power (torque), weight, and cost. These are weighted based on target market (pick two). Efficiency doesn't come with any of the above. Also note that power tool motors needn't be rated for continuous operation. I think that's going to be your biggest problem.

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amdx 10 years ago

OK, I was still think drills.

The torque wrenches look very powerful.

Mikek

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John Doe 10 years ago

Of course power is important. But given a specific power, battery capacity and efficiency determine run time. And run time is everything in powerful cordless tools that suck current.

Go to DeWalt's website and look at their new brushless motor powered drills. The first three listed qualities tout efficiency and run time.

Product Features

DEWALT-built high power, high efficiency brushless motor--650 unit watts out (UWO) max power for superior drilling & fastening applications performance--delivers up to 57% more run time over brushed

XR Li-Ion batteries with fuel gauge provide 33% more capacity over standard packs

3-speed, high performance (0-2,000 RPM) all-metal transmission optimizes tool-to-task for fast application speeds and improved run time

YouTube videos that test cordless drills usually compare the amount of work they can do on a single battery charge. Again, it's about efficiency.

krw wrote in news:tkbkua150ed2ilkidv63kqn51r51vpn7jl@

4ax.com:

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krw 10 years ago

Wrong. Weight is far more important than run time, particularly at the upper end (though DeWalt is certainly not even near "upper end"). Again, it's a balance based on the target market. Run time isn't even in there, though.

Why? DeWalt is crap. Has been for years.

It's a metric that no one cares about. There is a reason DeWalt has been a bottom feeder for years. I bought several of their tools a few years ago. The only one I still use is the circular saw but not often.

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John Doe 10 years ago

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