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Best Variable Speed Controllers for Power Tools

Variable speed drives and controllers start and control the speed of power tools. The power tool motors operate with direct current, and the variable speed controller cuts the current at a more or less high rate to finely adjust the speed of the motor. We can compare it to a large variable resistor. You must by a speed controller according to the consumption needs and the power tool configurations. This article explains the functions and types of variable speed controller for power tools!


In a Hurry? Here are Our Top Choices


But to understand the role of speed controller, let’s first discuss what power tools are and how they operate!


Types of Power Tools

Repairing a piece of furniture, repainting the garden furniture, assembling a cabinet, or renovating a room, etc., to carry out all this work, it is essential to have the right tools on hand. Don’t hesitate to invest in power tools that are both powerful and versatile: you won’t regret it! Some of the most useful power tools include:

  • drills or hammer drills
  • cordless screwdriver
  • circular jigsaws
  • sanders or grinders


The source of energy for a power tool is of course electricity. When you have to choose power tool, whatever it is, you are confronted with many technical data: direct or alternating current, voltage, intensity, voltage, Watts, etc.


There are two types of currents:

  • Direct current (DC): An electrical flow that travels in one direction only, from the power source to the device that uses the energy.
  • The Alternating Current (AC): This is the electrical energy that is most used. Unlike direct current, the electrical flow does not move in one direction but both directions alternately of a few milliseconds.


 Voltage, Intensity and Watt

When you consult the data sheet for a power tool, you often come across these different terms.

  • The electrons circulating inside a conductive material generate pressure, which is the voltage and is measured in Volts. When choosing a power tool, voltage in Volts is one of the first indicators to check as it is the strength or power of your tool.
  • Intensity is measured in Amps and represents the quantity or volume of electricity flowing inside a conductive material. When choosing your power tool, it is also very important to consider the intensity of the batteries because the more intensity you have, the longer the battery’s autonomy will be. Concretely, 4Ah batteries will have a much longer autonomy than 2Ah batteries.
  • Watt (W) is a unit of electrical power that you get by multiplying volts by amps.


When choosing your power tool, you should prioritize voltage if you want a powerful tool. On the other hand, if you need significant autonomy, it will be necessary to privilege the intensity. Likewise, the real power of a tool is not measured by its base power but rather by its useful power.


Variable Speed Controller for Power Tools

Brushless motors operate on three-phase of currents and need to be driven by a controller to transform the direct current of the batteries and make them turn. They supply current to each coil alternately to drive the rotation of the motor.


Variable speed controllers are designed to provide efficient speed control of the power tools and get the most out of DC and brushless motors. They are compact, easy to use and highly dynamic used to:

  • control the speed of DC motors
  • control Brushless motors’ speed (analog or digital Hall effect sensors)
  • control the speed of Brushless motors with AES
  • control the speed of brushless motors


You can use different flexible motor and sensor combinations on the speed controller according to the size and delivery condition to use them in various applications.


Choosing the Right Variable Speed Controller

Choose a brushless controller (just like a brushless motor drive) according to the consumption (A amperes) and the voltage (V volts) of the motor that it will have to operate. To know these elements, look at the technical characteristics of the engine generally provided by the manufacturer of your power tool. Size and weight will also matter depending on the model for which it is intended.


It is recommended to over-size the speed controller by about 50% compared to the current (A) that it will have to withstand to guarantee optimal and especially long-term operation. For example, if your power tool motor consumes 40A, choose a controller supporting up to 60A.


There are Bec, U-Bec or Opto controllers.


BEC (Battery Eliminator Circuit)

This configuration allows this to pass a separate power supply for the receiver and the servos. The propulsion battery will power them through the controller. This configuration is suitable for mid-size models, using no more than four standard-size servos.



As for the BEC, the voltage is regulated, and they can deliver higher currents to supply the servos. More reliable than BECs, the U-BEC also has its limits. It is imperative to consult the controller manufacturer’s manual to know the number and consumption of the servos supported.



OPTO controller only provides power to the motor, and it will require a U-Bec or a battery dedicated to power the servos and the receiver.


You can use a separate power supply if you have a BEC controller, but you must cut the red wire from the socket to the receiver.


Most brushless controllers offer configurable options using a programming card (the most practical and user-friendly, you can configure the controller even in the field), with the throttle stick of the remote control or by a USB interface via a PC, provided that the manufacturer offers it.


The Best Variable Speed Controllers for Power Tools

ALL-CARB Router Electric Motor Fan Rheostat Variable Speed ​​Controller AC 1500W / 120V / 15A

JOD Router Fan Variable Speed ​​Control for Rheostat AC 120 Electric Motor Power from 500w to 1800w Adjuster

DC motor speed controller, 6-60V, 12V, 24V, 36V, 48V, 30A, PWM, DC motor speed regulator, variable speed control switch, toggle switch switch starter switch

120V DC motor speed controller, for power tools, woodworking equipment

WFLNHB Variable Speed ​​Controller for Router Fan, Rheostat AC 1500W/120V/15 Amp Electric Motor


Depending on the configuration of your power tools and your consumption, you can select a variable speed controller that best suits your power tool.


Our Final Thoughts

Now you know what the technical data mentioned on the product sheets correspond to. You have all the keys to choose the variable speed controller for power tools! Choose a speed controller according to your power tool motor’s consumption (A) and the voltage (V).


About Chris

When Chris first bought a house, he quickly realized that he was now going to need to be a weekend handyman. Every project that he worked on, he kept realizing that he needed more and more DIY tools. Chris is also someone who likes to do a lot of research before making large purchases. Since he had already done most of the research, Chris decided to put the info that he accumulated about his favorite daily tools onto