If you are into RC Cars you can’t avoid hearing about ESC or Electronic Speed Control as the full acronym spells out. But let me explain what it really is and how it fits into the RC Car world.
What is an RC ESC? It’s a common knowledge that RC cars’ servo motors contain electronic circuits. The ESC’s purpose is to adjust or alter the speed of the servo, its control, and so operate as its dynamic brake and this is called Electronic Speed Control (ESC) of RC.
Your curiosity must be building up further after reading this tiny yet profound detail. We know, now you want to acquire additional knowledge about the speed control system of RC cars. We have gathered all the useful information for your experimental minds, so read on.
How does an ESC work?
The whole term, electronic speed controller gives you an overall idea of its basic function which we already discussed in the aforementioned paragraph briefly. Here’s how it really works. Based on the location of the throttle stick, it adjusts the volume of the speed of the electric motor from the RC car’s battery.
They usually provide three-phased electronically generated power to the motor which allows much smoother and efficient motor speed than the mechanical type. The ESC converts the motions transmitted by the receiver.
The first wire is plugged or connected to the main battery of your RC car. The second wire consists of a servo wire that connects with the receiver’s throttle channel and for operating the motor, the third wire is used.
Now obviously, the mechanisms of electronic speed controller vary in various models of RC cars and other RC vehicles. The types of ESCs are mentioned in the specifications of your RC vehicle when you purchase it.
There are some current electronic speed controllers which vary in the amount of power. Instead of a mechanical device, a MOSFET transistor is used as a switch. It switches at about 2000 times per second.
The power that the motor receives is diverse against an off time in a specified cycle as the changes occur in the amount of on time. Basically, the Esc absorbs magnetic energy stored in the curvature, when the MOSFET is switched off. The magnetic field in the curvature of the motor increases when the current upsurges, this happens when the MOSFET is switched on.
Now that we have discussed the mechanisms of an ESC in detail, let’s learn about its other features.
What are the Two Types of ESC?
The two types of electronic speed controllers are brushed and brushless speed controllers. A significant point to note here is that there are two similar types of electric motors. Meaning, a brushed electronic speed controller is used in brushed motor type and the brushless is used in the brushless motor.
The system of electronic speed control is applied in different remote control and vehicle applications. Those are electric cars, electric bicycles, electric aircraft, cars, helicopters, airplanes, boats, quadcopters, and ESC firmware.
Make sure that you purchase the Esc according to your motor type. For the people who don’t understand these mechanisms, there are RC vehicle models like the RTR RC model in which the electronic speed controllers are pre-installed. Many of these models contain a brushed motor and speed controller.
What is brushed ESC?
The brushed electronic speed controller has been around for a long time and it’s much cheaper to purchase. The brushed ESC controls the voltage in the brushed motor which runs itself mechanically if the voltage is applied. The voltage is turned on and off rapidly according to the speed of the motor.
What is Brushless ESC?
The brushless electronic speed controller is the latest technology in RC vehicles and it’s expensive than the brushed ESC. Up till now, you have a basic idea about ESC that it needs a kind of signal to verify when to energize the pole from the motor and that’s why it needs brushes.
There is a three-phase AC power output created by the brushless electronic speed controller to operate the motor from a DC power source. So, it transmits a sequence of AC signals the electronic speed controller’s circuitry.
As there are 3 wires in a brushless motor, at any precise instant; the one pole which is not energized will produce a small volume of energy. The spinning motor is proportional to this small volume of energy.
At any given time, Esc consumes this slight voltage to determine the direction and speed of the motor. Through this information, the ESC recognizes how to transmit the power to the electromagnets.
The brushless ESC might sound complicated to you but in reality, it is considered better than the brushed one by most RC enthusiasts.
How do you Choose the Right One for You?
We discussed this briefly, in the above paragraph. You know by now that Electronic speed controllers are designed especially for a particular type of motor.
When you go to purchase an ESC for your RC vehicle, first match it with your motor type. Never get a brushless ESC for the brushed motor because that will not function at all.
People who are pro at this RC mechanics, they figure out the motor type from the number of wires it contains. If it is brushed then there are two wires and if there are three wires, then it’s a brushless motor.
A brushed motor can run without an ESC but you cannot run a brushless motor without a brushless ESC. The reason is that a brushless motor consists of three wires and it only works if the brushless ESC is connected. Whereas the two wires of the brushed motor can be directly connected with the batteries.
While buying an ESC, be aware of your choices and limits because just like all other products, you get what you pay for. If you want a total advanced performance for your RC car then a brushless ESC will be perfect for you.
If you are still in the learning phase, then we recommend that you buy a brushed ESC with a brushed motor for your RC car.
What is a BEC in ESC?
BEC stands for Battery Eliminator Circuit. These are present in the latest models of brushed and brushless ESC and the requirement of carrying an extra battery in the model is eliminated. The incorporated battery eliminator circuits control and stabilize the volume of energy to run the servos and receivers.
What are the different Types of BEC’s?
There are mainly two types of BEC’s, Linear or Switched mode.
The BEC that uses a resistor to bring down the voltage from 7.4v to 11.1v is called Linear. The five volts needed for the receiver, linear BEC is mainly used with the lipo battery packs to bring down those 5 volts. Remember that excessive current is harmful, it will overheat and damage your ESC or battery eliminator circuit. As the current flows over the resistor, more heat will be created if the lipo voltage is high and the RX will consume more energy.
Switched Mode BEC:
Remember we discussed the rapid voltage on and off previously? Well, that occurs in the switched mode of battery eliminator circuit. The rapid fluctuations of the voltage effectively bring it down without the excessive creation of heat and the electricity is not wasted in this way. Where the high power is required and your lipo battery consists of four or more cells, it is better to use a switched BEC.
In some RC models, there is no on/Off switch and you might get confused. The thing is when you connect the battery, the servo, receivers, and ESC through ESC BEC, so your transmitter stays on with the throttle being kept at Idle before plugging the batteries. But it will be better if you find an ESC with a BEC that consists of its own on/off switch.
What other components can be found in an ESC?
An ESC consists of many other components. They are listed below:
- State LED
- Solder jumper, for varying the type of the PWM input signal
- Servo signal or input of the PWM signal
- Solder jumper, for altering the direction of Rotation (CW/CCW)
- GND reference of PWM Signal
- Positive (+) LIPO Connection
- Negative (-) LIPO connections
- Solder pads for the 3-BLDC motor phases
Is speed control the same as cruise control?
Speed and cruise control may seem like two different terms to you but they both have the same function i.e. to control the speed of your RC car. In some countries, the term speed control is used and other countries use cruise control. To maintain a steady speed, it’s the servomechanism that dynamically takes over the throttle.