What To Do If The Steering Gear Voltage Is Too High? Symptoms And Detection Methods

Friends who play withservos must have encountered such a bad thing: the project was running well, but theservos suddenly stopped obeying the control, either shaking non-stop, or not moving at all, and even smelling of paste. Don't worry, it's probably a problem with the voltage of theservo. Excessive voltage is like a person suffering from high blood pressure to the steering gear, and is the source of many failures.

What are the symptomsif the steering gear voltage is too high?

Excessive voltage is a real hidden danger for the steering gear. The most direct symptom is that the servo is hot. If you touch it with your hand, if it is very hot, it must be abnormal. It will start not to obey the command. For example, if you ask it to turn 45 degrees, it will overshoot, or it will shake in place, just like a person shaking. If it's more serious, you may hear a sizzling noise inside the servo, which is usually the control chip struggling under overvoltage. If you smell a burning smell, it is very dangerous. The internal components may have been burned out, and the entire servo will be directly scrapped. In serious cases, your main control board may even be damaged.

How to measure the current voltage of the servo

If you want to know whether the voltage is high or not, you can't just rely on feeling, you have to use tools to tell. The most reliable tool is a multimeter. It’s not expensive. It’s best to have one when playing with electronic equipment. You adjust the multimeter to the DC voltage range, then use the red test lead to touch the positive power line of the servo (usually the red wire), and the black test lead to touch the negative power line (usually the brown or black wire), and the reading will be displayed on the screen. When measuring, you should choose to measure when the servo is in action, for example, let it rotate quickly, because the voltage when no load and when it is loaded is different. If the voltage is still very high under load, that means there is a real problem.

What is the standard voltage range of the steering gear?

Different servos have greatly different voltage requirements, just like mobile phone chargers. Some use 5V voltage, while some have fast charging functions and require a voltage of 9V. In this case, you must first understand the specific model of the servo you have on hand, and then consult its data sheet. Taking the most common micro servos as an example, such as SG90, their standard voltage is usually between 4.8V and 6V. However, some metal servos with high torque may have a higher operating voltage, which can reach 7.2V or even higher. Never assume that higher voltage means the servo will rotate faster. This is an extremely dangerous misunderstanding. Once the upper limit of the rated voltage is exceeded, it is like adding the wrong oil to the engine, which will inevitably cause big problems sooner or later.

In the use of servos, the voltage requirements of different types of servos vary significantly. Take mobile phone chargers as an example, some are 5V, and some require 9V for fast charging. Therefore, you must first find out the model of the servo you are using, and then look for its data sheet. Common micro servos, such as SG90, have standard voltages generally between 4.8V and 6V. For some high-torque metal servos, the working voltage may be higher, reaching 7.2V or more. Never rely on subjective assumptions that higher voltage means the servo will rotate faster. This is a very dangerous misconception. Exceeding the upper limit of the rated voltage is like adding the wrong oil to the engine, and serious problems will occur sooner or later.

How to solve the problem that the steering gear voltage is too high

If you find a problem, you have to solve it. If your power supply voltage is indeed higher than the endurance range of the servo, then you need to perform a voltage reduction operation. ️Replacethe power supply. This is the most fundamental way to directly replace the power adapter or battery with an output voltage that meets the requirements of the servo. ️Twoplus modules. If the power supply is difficult to replace, for example, you are using a lithium battery pack with a fixed voltage, then add a step-down module (also called a DC-DC converter) between the power supply and the servo to adjust the voltage to an appropriate value. This is like adding a pressure reducing valve to the water pipe, simple and effective. ️Threestrings of diodes. For some small servos with low current, you can use diodes in series to reduce the voltage by using the voltage drop of about 0.7V of the diode, but please note that the power of the diode must be sufficient.

Choose a high-power steering gear power supply

After solving the voltage problem, you have to pay attention to whether the current is sufficient. When selecting a power supply, there is a simple formula: the output current capability of the power supply must be greater than the sum of the operating currents of all servos. For example, when a servo is in a locked-rotor state, it may consume 1A of current. If you use two such servos at the same time, the power supply needs to be able to stably output at least 2A of current. If the current of the power supply is insufficient, the voltage will be pulled down, and the servo will be underpowered and may even reset.

Therefore, when choosing a power supply, don’t worry too much about the money. You should leave a certain margin. For example, if you calculate that a current of 2A is needed, you can buy a power supply that can output 3A or even 5A. In this way, the system operation will be more stable and the power supply itself will not overheat.

Does voltage instability have a big impact on the steering gear?

Voltage that suddenly goes up and down is more of a headache than being constantly high. This is usually caused by the power supply line being too thin, the solder joints having poor contact, or the power supply having insufficient power. If the voltage is unstable, the most direct reaction of the servo is to vibrate, making it impossible to position accurately. What's more terrible is that repeated voltage shocks will accelerate the aging of the internal capacitors and other components of the servo, which will greatly shorten the life of the servo in the long run. It's like riding a roller coaster. It's okay once in a while, but no one can stand it every day. Therefore, in addition to ensuring that the voltage is accurate, you must also check whether all connection points are firm and whether the lines are thick enough to ensure smooth current transmission.

Okay, let’s stop talking to you about the servo voltage. Have you ever had any problems with your servo due to voltage issues? How did you pull it off in the end? Welcome to share your experience in the comment area, let us all learn and progress together! If you find the article useful, don’t forget to like it and share it with more friends who play servos.