Dewalt 20v brushless drill - bad motor?

[Supa Dexta]

Have a 20v brushless dewalt drill, (can't remember the model # off hand) picked it up to use it today, hit the trigger and it ran for about half a second then nothing. Took it apart and if I turn the motor just a bit, it will run for that half a second and quit again.

Does this mean the motor is bad and it just turns to the bad spot and quits again, or should I be looking towards the trigger or something?

 

[Xcursion88]

Have a 20v brushless dewalt drill, (can't remember the model # off hand) picked it up to use it today, hit the trigger and it ran for about half a second then nothing. Took it apart and if I turn the motor just a bit, it will run for that half a second and quit again.

Does this mean the motor is bad and it just turns to the bad spot and quits again, or should I be looking towards the trigger or something?

Assume you've verified the battery is perfectly satisfactory

 

[Supa Dexta]

Assume you've verified the battery is perfectly satisfactory

Correct, multiple batteries tried, they work fine in other tools.

Turn the motor on the drill> get the half second run time and it quits, turn it to a new spot and try again and its pretty repeatable.

 

[Rabid Badger]

Sounds like the motor position sensor isn't talking to the computer. Did you inspect the wiring for damage and/or loose connections?

 

[kelpaso1]

Sounds like the motor position sensor isn't talking to the computer. Did you inspect the wiring for damage and/or loose connections?

Gezz, do we need car like electronics to control a simple drill???

 

[Xcursion88]

Correct, multiple batteries tried, they work fine in other tools.

Turn the motor on the drill> get the half second run time and it quits, turn it to a new spot and try again and its pretty repeatable.

What about bumping it?

 

[Supa Dexta]

Yes, bump, jiggle, knock, twist - no difference around the battery connection.

There is something going on where by turning the motor position slightly, it allows it to start again for that brief moment.

 

[FMB4]

Sounds like a Hall Sensor issue. A short circuit could also be tripping an Overload Protection circuit (if so equipped). However, the fact that you need to "turn it to new spot" in order to get it to run again suggests a failed Hall Sensor or HS related circuit.

 

[FMB4]

You might consider cleaning the motor. There several brands of brushless DC motor spray can type cleaners as well as a bunch of online videos that detail the general disassembly, cleaning, and reassembly. There might even be video of your exact drill, or a model very similar to it.

 

[finn]

Gezz, do we need car like electronics to control a simple drill???

What’s your suggestion? Abandon brushless technology and go back to the old, inefficient brush motors?

Maybe stay with corded tools?

You have options.

 

[American Locomotive]

I would try cleaning everything and making sure nothing is bound up. Sometimes if metal filings get on the sensors, they can cause them to do weird things.

I don't know which particular drill you have, but DeWalt's parts prices for their brushless tools are obscene. They only sell the motors/switch/driver as an assembly, and the list price for that assembly across most of their drills is usually HIGHER than the cost of the entire tool.

Gezz, do we need car like electronics to control a simple drill???

A brushless motor requires the motor driver to know exactly where it is, so yes.

 

[engineer2]

Easy thing to try is to blow it out with compressed air.
If that doesn't work, time to disassemble it to see if there are any obvious issues.

The new brushless tools have electronics to protect the battery, protect the motor, provide speed control, optimize power as the battery drains, among other functions.
I like them better than the old brushed motors that would emit white smoke if you overheated them.