Introduction

Vertiq has designed its next generation of modules to accommodate Add-Ons to meet customer needs. One of Vertiq's goals for these modules is ensuring the system is able to handle a variety of environmental factors, such as sand, dust, and water. With these Add-Ons, the max IP rating of Vertiq’s next generation modules is IP45 and in this post, we will explain how we achieve this rating. See the chart at the bottom of this post to get more information about the IP rating numbering system.

For a BLDC motor, too much dust or sand in the coils will add friction, making it less efficient. Too much exposure to water will wash away the bearing grease, limiting the lifetime of the motor. For ESCs, dust and sand do not have much impact on performance, but exposure to water could cause a short, which would result in a critical mid-flight failure. Protecting the motor and ESC from solid and liquid ingress will allow the propulsion system to operate in hazardous conditions and prolong its life, allowing for more reliable and versatile aircraft.

There are three areas of the module that require attachments to maximize IP rating: the top of the rotor, the middle section beneath the coils, and the bottom of the stator. Vertiq has therefore created a Rotor Cover, Coil Guard, and Stator Cover, respectively, to protect these areas from solid and/or liquid ingress. Before looking at the Add-Ons, it is important to understand the IP rating of the core motor and ESC to which Add-Ons are attached, as well as the Default configuration of the module.

Base Module

Vertiq modules all have a “Base” Configuration, which includes just the motor and the ESC. Add-Ons are then attached to the Base Module to increase usability, functionality, and reliability. Vertiq has made some internal design improvements to limit water getting to and through the bearings. As a result, the motor part of the module (not considering the ESC) has an IP rating of IP15, as it allows solids >12.5mm to enter but is protected against jets of water. The ESC is conformal coated, but it is completely exposed in the Base module configuration. As such, we assign the ESC compartment a rating of IP61, as it is not affected by solid ingress but it is not well-protected from liquids . Taking the lowest solid and liquid ratings from both the motor and ESC gives us our overall module rating, so the IP rating of the Base Module is IP11.

Default Module

Vertiq’s off-the-shelf offering is the “Default” configuration of the module. The Default version of the module has a Solder Pad Connector Board that attaches to the ESC and a Stator Cover that pairs with this specific connector. The Stator Cover surrounds the ESC but allows the Solder Pad Connector Board to stick out, exposing power and communication pins for customers to solder wires to. As such, the Default module is IP13, as the motor remains uncovered but the Stator Cover protects the ESC from splashes of water. The intent of the Default version of the module is to allow customers to quickly test the performance of the motors. From there, Vertiq works with its customers to customize many aspects of the module, including Add-Ons to increase its IP rating:

Rotor Cover Add-On

In the “Default” version of each module, the top of the motor has its coils exposed. This configuration allows for air to flow freely through the top of the motor and minimize weight. Unfortunately, it also allows sand, dust, and water to easily enter the rotor. So, Vertiq created Rotor Cover Add-Ons to attach to the top of the motor.

There are multiple types of Rotor Covers, each of which accomplishes a different task:

Blower Fan: One version of the Rotor Cover is a blower fan. This attachment protects the top of the rotor from 5mm solids, making the top of the motor IP25. It also sucks air through the coils to more effectively cool the motor as it is spinning, increasing the continuous torque output of the motor.
Mesh: Another version of the Rotor Cover is a mesh screen. The mesh has openings of 0.8mm, allowing users to increase the IP rating of the top of the motor to IP45.
Combination: The blower fan and mesh are designed to be paired together, so you can increase the IP rating to IP45 while also keeping the motor extra cool.

Coil Guard Add-On

In the “Default” version of each module, the area beneath the coils is also exposed. This configuration allows for air to flow freely through the bottom of the rotor and minimize weight. Unfortunately, it also allows sand, dust, and water to easily enter the rotor. So, Vertiq created Coil Guard add-ons to attach to the middle of the module.

The Coil Guard add-on ensures all pathways that lead to the motor coils go through an opening of at most 0.95mm. This means the IP rating of the middle section of the motor is IP45. When paired with the Rotor Cover mesh, the entire motor becomes IP45. It should be noted that unlike the Blower Fan Rotor Cover add-on, the Coil Guard restricts airflow through the module, so users should expect a lower maximum continuous torque.

Stator Cover Add-On

The Stator Cover is a machined aluminum or 3D printable part that is highly customizable. In the “Default” version of each module, the Default Stator Cover shields the main ESC and is compatible with a Solder Pad Connector Board. This configuration allows for users to easily test Vertiq’s products by soldering powering and communication wires directly to the module, but the Solder Pad Connector Board sticks out and electronics are exposed to the elements.

In most cases, to maximize the IP rating of the ESC compartment, a Stator Cover design must interface directly with the arm of the vehicle and accommodate an O-ring placed in a groove in the Stator Cover, creating a tight seal between the arm and module when they are screwed together. Typically, this requires a downward eject connector or flying leads, and fortunately, Vertiq has designed its modules to accommodate custom connectors. The O-ring seal will allow the ESC compartment to achieve a rating of IP65. So, when the module includes the Rotor Cover Blower Fan and Mesh, Coil Guard, and sealed Stator Cover, the entire module is IP45.

The ability to customize Stator Covers and Connectors will also allow Vertiq’s partners to more seamlessly integrate Vertiq products into their vehicle, optimizing performance, reliability, and the final assembly of their aircraft.

IP Rating Chart

Below is a table showing how the add-ons to Vertiq’s modules affect their IP rating.

Add-Ons to Increase IP Rating