Introduction to Understanding Motor Datasheets
Overview
Here at Precision Microdrives, we want to make the process of selecting parts and designing them into applications as easy and pain free as possible. We're working on this by offering as much information about our products as we can, via comprehensive datasheets, application bulletins, and how-to guides. We've also got experienced application engineers on hand to respond to your enquiries. But despite all this, we understand how frustrating it can be to have everything in front of you, but for it to not make sense or appear overwhelming.
So, to suppliment our in-depth datasheets, we have produced this guide to reading them. Understanding the data and how to interpret it will allow you to make more informed decisions, getting the most out of our products and reducing your design risk. This guide is also written to be very accessible, so you can drop in and out as you please.
However, we do recommend reading the Datasheets Overview (immediately below) - it covers how the guide is structured.
Datasheets Overview
Firstly, we should mention the important difference between specifications and characteristics.
Specifications are oriented around providing accurate ratings or limits, such as Rated Voltage or Maximum Operating Current. However, these sometimes do not offer the full picture of the device behaviour and therefore the datasheet also contains characteristic data. Characteristic data is useful information, extrapolated from our device tests.
For example, consider the value Minimum Vibration Amplitude of a vibration motor, found in the Conformity Limits Specification table. If the motor does not meet the stated value, it is deemed nonconformant and is rejected. However, this specification does not tell the user what they can typically expect from a normal working motor. To solve this we include characteristic values such as the Typical Vibration Amplitude, found in the Typical Electrical Characteristics table. Characteristic values are for design guidance only, and they are often labelled typical values. They offer designers the opportunity to evaluate how the device would be expected to perform in their application, before they receive the part.
To summarise, the motors we sell are guaranteed to meet the claimed specifications, and they are likely to perform around characteristic data values.
Now, we've clarified the difference between specifications and characteristics, lets move onto reading the datasheets. On the front page of our datasheets we present a photo of the product, information about the product range it sits within, graphical performance information and a Key Features box. The key features box is designed to provide easy access to some of the most important information for quick comparison, and it includes both specifications and characteristics.
Different motor types will have datasheets with different information sections. The table below summarises what information sections you can expect depending on the type of device you are looking at. From the table we can see that DC Motors and DC Gearmotors contain the same sections, as do Vibration Motors and Brushless Vibration Motors. To make the guide quicker to read, we have grouped these four different device types into two categories. Linear Resonant Actuators are covered separately.
You will notice the values provided can be descriptive, an absolute rating with tolerance, or a minimum or maximum rating. We also use peak-to-peak values for the vibration amplitude. You can convert our values in G to standard values using the following conversion ratio:
The examples below are taken from the datasheet for a 5mm vibration motor from our Pico Vibe™ range, model 304-109.
Understanding Motor Datasheets Navigation
This guide now splits into the following categories:
- DC Motors and DC Gearmotors
- Vibration Motors and Brushless Vibration Motors
- Linear Resonance Actuators
- Summary and description of the tests we perform
You can continue with the type of device you are interested in by clicking one of the links below.
