Mounting and Cooling

the micro drive lpi offers 6 mounting holes to secure the unit to your cooling solution/aircraft these are best suited to m2 \[#2 56] socket head bolts ensure you use a tightening torque appropriate to the fastener and mounting material you are using the mounting holes accommodate a head diameter/ washer diameter of 4 mm \[0 15 in] the correct installation of the micro drive lpi relies heavily on ensuring proper isolation the bare board contains numerous exposed contacts, including a significant area of exposed live copper opposite the mosfets this particular region serves to enhance thermal transfer for the inverter bridge establishing adequate electrical isolation for the board is imperative to prevent potentially hazardous short circuits as a rule of thumb, there must be minimum 0 6 mm \[0 023 in] air gap between exposed contacts and any conductive materials in the mounting assembly all direct contacts to the unit, especially the thermal interface materials (tim), must be electrically insulative keep out zones for the micro drive lpi can be found in the cad available from our datasheet the micro drive lpi board should not be placed under high stress and torsional loads to appropriately compress the tim between the motor controller and the cooling solution, the micro drive lpi should be mounted in a floating arrangement this specific area to cool is identifiable by the presence of six mosfets on one side and the exposed copper thermal transfer pad on the opposing side a backing plate that contacts the copper cooling surface (and has clearance for the surrounding electronics) should be used in conjunction with a compression plate on the mosfet side to sandwich the micro drive lpi see the diagram below for details the micro drive lpi is a bare board motor controller with exposed electrical connections contact with water or significant amounts of dust/particulate can result in unit failure ensure that the micro drive lpi is mounted in a location with appropriate environmental protection to reflect the uav’s operating conditions cooling considerations the heat generating components on the micro drive lpi are highlighted in the below drawing the micro drive lpi has a particularly high power density, making effective cooling a challenge to ensure the micro drive lpi can operate continuously at the required phase current, you need a cooling solution that can effectively dissipate the thermal power from the unit to ambient it must do so while keeping the mosfet's and the electrolytic capacitors within their operating temperature to find power dissipation and temperature limit calculations, please consult our technical datasheet