All about Speed Controllers
by Roger Harper

Page 3 of 5

This is the next step up from the Wire Wound - Resistor Type speed controls.  These controls are designed to be activated by servo.   This type of control can handle a voltage from 3 to 12 volts.  Other may even handle more.

These controls offer Smooth Digital-Proportional Control. This gives you smooth control over a large rage of speed settings.  These controls should be used in scale ships and boats that use slow speeds to maneuver. 

With a better control comes a higher price.  These controls can easily be burnt out if not selected correctly.  It is important to select a control that will handle the amps of the motor(s) you plan to use with the control.  Know the requirement of your model before you order one of these units.

Electronic  Variable Types (Radio Operated)

This type of speed controls are known as an Electronic Speed Control or an ESC. ESC's like these even come in a few different "flavors".   Although some are different, they all plug directly into your receiver, removing the requirement of a servo to activate it.  I will try to cover this group in more detail, as this is the way I recommend you to go.  These speed  controls can satisfy both the race demon, or the scale buff.  No matter your type of boat, you can find one of these units to meat your needs.

How Does It Work?

ESC's, control the amount of voltage flowing from the battery on it's way to the motor.  These units are plugged into your battery, and they have motor leads that go to your motor.  The picture above is an ESC that does not use "high-frequency".  A

high-frequency ESC works by chopping the voltage delivered to the motor. At half throttle, the ESC delivers full voltage to the motor half the time, and no voltage to the motor the other half. The faster the voltage is switched on and off the smoother the motor runs.  High-frequency ESC's give you better control, are more efficient at partial throttle (give longer running times), and help the motor last longer. That's why you want one. Tekin and Novak don't make anything else.

How Many Clams To Shell Out?

ESCs range in price from around $30.00 to over $100 dollars. The biggest item to deal with ESCs is how much resistance the ESC has. Resistance is basically how much power is lost when going through the speed control. Less is better for you get more run time and faster speed. Also, the less resistance an ESC has, the less heat it generates.   

The less expensive ESCs can overheat, and I would avoid them. I would recommend buying an ESC that has the capability to run stock to lightly modified motors down to 15 turns.  Remember that this is a control made for R/C cars, trucks and buggies.  Therefore, we need to make sure I use their lingo. Also, you must know the maximum number of "cells" you can use.  One cell is a sub-C and has a voltage of 1.2 volts.  So IF I have a 12 volt system, I need to make sure the ESC I get can handle at least 10 cells.  (10 Cells X 1.2 volts = 12 volts)

Reverse, Don't They All Have It?

Reverse is a feature that is not in all ESC's.   Reverse in not allowed in some car races, so most of the ESC's out there are forward only!  In the boating world, if you have a race boat this would be fine.   But if you have a scale boat, reverse in a must.