There's plenty of fish in the sea, and there's plenty of high power electric motors in the online shops. According to researchers, the servo motor market was valued over 6 billion in 2018 and may grow by more than 6% by 2025. How to know which electric fish is a gold one and will make all your business wishes come true (or at least some of them)?

Keep calm and do this small 5-step research within your company. Be careful: good research may show some hidden business problems that you’ll have to deal with (or ignore).

1. What should this electric motor do?

There is a big difference between giving some precise motion to a conveyor belt or to an optical microscope. As Captain Obvious says: Different applications = Different types of servo motors.

Three main types of power electric motors depending on the motion type are:

• Positional rotation servo motors
• Continuous rotation servo motors
• Linear magnet servos

Positional

It’s the most common type of electric magnetic motor. Why is it called positional? Because of a small integrated physical mechanism stopper. It detects the position of the rotor and stops it from moving further than half the circle or 180 degrees. This type is the lowest-cost option among others as it’s primarily designed for low-tech applications. However, after some challenges you can turn it into high power motor for robotics with a necessary repetition frequency.

Continuous

Continuous rotation servo is an updated version of positional: it goes in any direction indefinitely. The sensors control the speed and the direction of the actuator. The range of potential commands is extended from moving the motor shaft to a certain position to rotating clockwise or counterclockwise with changing speed. The continuous rotation gives it a greater flexibility and energy savings.

Linear

Continuous servo is like Positional 2.0. And linear one is Continuous 2.0. It consists of a stator, coil assembly, magnets and extra gear system that transposes circular motion to linear. Magnets allow the drive to achieve its higher force, precision, and repetition frequency.

The illustration below shows common applications for each motor:

When your business is servo based, it is essential to use not any servo, but the right one high power electric motor. In addition to the motor type, plenty of factors should be considered: supply voltage, rated power, peak torque, gear type, etc.

A low-cost motor option can be attractive for your budget but, as a rule, cheaper electric motors are less durable, less precise, and less effective, too. If your project isn’t electric RC toys but industrial manipulators for automated welding, invest more in supplies.

Because, and don’t try to DENY IT, the only free cheese is in the trap for a mouse and a miser pays twice.

2. Where do you want to apply your servo?

In the product description of any actuator, you will find two important features: operating temperature and IP Rating. These two parameters limit the application area.

So if you plan to build a machine for throwing the Ring in the volcanic fire or to cut out Captain America from a block of ice, read motor’s performance data first.

IP Rating is a worldwide standard system. According to it, each actuator is estimated and given a special number. Each double-digit code has a specific meaning: it shows how effective the drive is against external influence.

The first number indicates the degree of protection from foreign bodies (dust, fingers, and sticky beaks). The second defines the protection level from different types of moisture (drops, sprays, engineer’s tears).

The list below might help you when choosing a motor:

First Digit

1. 1 or X means there is no data available or there is no special protection at all
2. Protection from objects bigger than 50mm in diameter
3. Protection from objects greater than 12.5 mm in diameter
4. Protection from objects starting from 2.5 mm in diameter
5. Protection from >1 mm bright objects
6. Dust protected
7. Permanent dust tight

Second Digit

1. Resistant to water equivalent to 1 mm rainfall per minute
2. Protection against vertically falling drops, such as condensation. Water equivalent to 3 mm rainfall per minute
3. Resistant to water falling as a spray up to 60° from vertical
4. Waterproofed against the sprays from any direction
5. Protected against nozzle (6.3 mm) from any direction
6. Protected against powerful nozzle (12.5 mm) from any direction
7. The equipment works with immersion for up to 30 minutes at depths between 15 cm and 1 meter
8. The equipment is suitable for continuous immersion, generally up to 3 m
9. Protected against extended immersion under higher pressure with high temperature

And yes, in order not to get ANGRY because of overheated or contaminated motor, follow the terms of use.

3. What is your budget?

Prices given on servos in online stores can be tricky. Do not rush to push the Order bottom until you find out the following information:

1. Is it a fully equipped motor? Does it have built-in encoder, controller, and gearbox? Or should you purchase these parts extra?
2. Does the given price already include VAT?
3. Is the warranty period provided? If yes, for how long? Does it cover the estimated ROI period?
4. Is there a manual provided (in your language)? If no, does the company provide tech support on servo installation?
5. Are there extra charges for minimal or small orders?
6. What is the delivery time and fee? Who provides delivery?

These points may seem unnecessary, but let's imagine: you found some pretty trustworthy looking, strong and affordable high power electric motor on Amazon. You’ve rejected Amazon Prime in order to fit in your budget. And here it is, in two weeks, at the front door of your office. It looks like a motor, it smells like a motor, but you have no idea how to start with it. There is an assembly guide but it’s written in some type of language that neither you nor Google can recognize and you can not read it. You’ve managed to install it after 8 hours of suffering and STEM challenges. And yes. It dies in 10 weeks. 6 months warranty is a slight relief. You saved your budget but sacrificed your time and nerves.

Another possibility. You’ve chosen an electric motor on the official website of a producer, ordered it, but didn’t consider the VAT, delivery price, motor integration. The final price is very different to what you’ve planned.

What could help here?

Reasonable budget planning. Once again – if you work on a project with no need for extraordinary quality, effectiveness, etc. you don’t need to invest too much in motors. But if this high power electric motor will drive some company’s core product, don’t try to BARGAIN HERE. Better to invest once than to suffer twice. Still, you can use some well-known tricks to save some budget – check the producer’s website to find if there are any sales, cyber weeks, special offers, etc.

To sum up

It’s ok if you feel a bit DEPRESSED after asking yourself all these questions. But it’s better to find out a problem, ACCEPT unpleasant truth and start working on it instead of living with comforting lies. Start your way to conscious choice of a servomotor and, if any help needed, don’t hesitate to ask. Our specialists went already this long way of trials and mistakes from the first wiring to an effective motor, so we would be glad to share this experience with you.