Brushless Motors - a Toolstop Guide
Posted by Mark Hunter - May 24, 2012
We hear it all the time. A power tool manufacturer has some sort of "new innovation" that makes their tool "best in class", or some such. It's easy to become numb to these proclamations, what with their corresponding marketing campaigns complete with pie charts and infographics.
However, we reckon the move towards brushless technology is one innovation we should all sit up and pay attention to.
It genuinely is a game-changer.
Here's the facts.
In that power drill you brandish all day on the jobsite (or any AC/DC electric motor-powered tool for that matter) you're likely to have carbon brushes. The motor in your power tools is usually made up of 6 parts:
- Armature or rotor
- Field magnet
- DC power supply of some sort
The power supply in a cordless power tools is, of course, the battery. The battery supplies the current to the motor, the motor spins and powers your tool.
We don't want to get all Stephen Hawking on you, so we'll just let DeWalt's John Westland explain how DeWalt has used brush-less motor technology in their new DCF895 impact driver. Click here to watch the video on Youtube.
We promise you, this is in Plain English.
So, while common and historical, brushed motors have problems:
- conventional brushed motors are typically bulky and heavy. This translates itself into bulky, heavy power tools which are tiring to use
- brushed motors, due to their very nature, produce sparks and heat. These are forms of "energy loss"; in the case of a cordless tool, this energy - even though it is lost to you - is drawn from the battery. Your cordless battery's life is potentially shortened. Lost energy means more charges, more charges shorten the life of the battery
- the brushes themselves wear and and need to be replaced. This costs you time and money
So, what advantages does going brush-less have for you and your power tools on the job site?
- a brush-less motor is inside-out to a brushed version, and as the name suggests, eliminates the need for brushes. The windings are on the outside and a permanent magnet is fitted inside
- less energy is required. And because less energy is required to charge the permanent magnet to get the motor running, batteries last longer
- no sparks are produced, and the motor runs much, much cooler. Again, this translates to your tool being able to run much longer on a charge because there's less "energy loss"
- because of the nature of their construction, brush-less motors are light and smaller. This translates itself into smaller and lighter power tools that run longer
What tools are already brushless and can we expect to see more of this technology being used in the future?
We'd offer the opinion that, firstly, much like lithium-ion battery technology, brushless motors are going to become more and more prevalent on the market. It just makes sense;
- they run more efficiently
- they allow for lighter and smaller power tools
- they're maintenance-free
Name 3 more useful improvements to your power tools and we'll give you a toffee*.
Secondly, the smart power tool manufacturers are investing in developing this technlogy, so we expect to see more brushless motors in power tools in the future.
In addition to the DeWalt DCF895, Makita have a brushless motor-powered impact driver, the BTD145. It's also a wee cracker, and you can check it out here:
We'd love to hear what you think of brushless motors, so talk with us via the comments below or on Twitter using #DIYTradetips.
*we won't actually give you a toffee.
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