RC Driver Magazine - Article - All About Speed Controllers

RC Driver Magazine - Article - All About Speed Controllers: "All about speed controllers
by Gary Katzer garyk@rcdriver.com
Few things in the industry have evolved over the years as much as the speed control. What started as a large, power-robbing wiper / resistor setup is now a highly efficient fully electronic unit roughly the size of a mini post-it pad. Electronic speed controls receive signals from your radio and receiver and translate them into motion with an infinite range. It�s not too technical at all. Read on to understand the differences between mechanical speed controls and electronic units.

MECHANICAL SPEED CONTROLLERS (MSC) WHAT IS IT?
A Mechanical Speed Control (MSC) is a mechanical device that regulates vehicle speed. RC History lesson: MSCs were originally based on slot car speed controls. An MSC for an RC car is made up of several components similar to those found in a slot car control. These include a contact board with wiring and wiper arm and, to fit it to a car, a throttle servo and mounting bracket. Early MSCs often included a four-cell AA battery receiver pack, but in recent years most have included battery eliminator circuitry (BEC) that powers the receiver with current taken from the drive pack.

The MSC�s job is to deliver power from the battery to the motor in gradations so that you have the ability to reduce or increase vehicle speed. The position of the wiper arm on the contact board (a kind of resistor) increases or reduces the amount of power that gets to your motor. When the wiper arm is at a slow speed position, the MSC burns off a certain amount of energy as heat that is lost through the resistor. This process is relatively inefficient, reduces run time and doesn�t offer as smooth a throttle response as an electronic speed control (ESC).

MAINTAINING AN MSC
While most enthusiasts eve"