# AB-027 Released : Eccentric Mass Parameters for Vibration Motors

How are we able to achieve different profiles and characteristics in ERM vibration motors? Well, given we know the vibration force is based upon the formula below, there are two parts that we can customise:

$$F = m \times \ r \times \omega^{2}$$

The easiest is changing the DC motor, where different torque and speed constants will inevitably impact on the angular velocity, ω, leading to different vibration strengths and frequencies.

However, we can also see that the eccentric mass plays a huge part too – both the values for m and r are directly related to the masses characteristics. In addition, as the motor performance is dependant on the load

So what do we need to know about our eccentric mass in order to accurately model the motor? Well, that’s the topic of our latest Application Bulletin. We discuss two types of eccentric mass, guiding you through the necessary formulae and including a worked example using a real ERM. Click the link below to gain access:

AB-027: Eccentric Mass Parameters for Vibration Motors