Johnson Electric PLG Motor

Basic Overview

Figure 1: PLG motor comparison 

This PLG motor (Power Lift Gate) is used in automotive applications to open and close the lift gate in SUV’s etc.   In most applications the motor drives a lead screw that provides translational motion.

Note:  Starting in January 2022 an updated motor will be provided to teams since the previous version will be discontinued.  The new motor will be offered in FIRST Choice and for sale at AndyMark starting in January 2022.  The old version (JE-PLG-149 / AM4233) will continue to be for sale at AndyMark until stock is depleted and then will no longer be available.

The following is a comparison between both versions:

Performance

Motor performance can vary from motor to motor.  The limit line represents the range the motor could vary across the population.  It is always best to plan for worst case performance when sizing the motor.

Figure 2: PLG Motor performance curve

Electrical connection

An FRC approved motor controller is required to interface with this motor.  Refer to the latest version of the rules for restrictions and requirements.  Only the black and red wires are needed for motor operation.  The 4 hall wires (Brown, Yellow, Green and Blue) are optional if teams would like motor feedback and are not required for motor operation.

Figure 3: Wire labeling quick reference.  The 4 hall wires are not required for motor operation.

The following figure represents a minimum hookup configuration for motor operation.  If directional control is not required it is an option to use an FRC approved relay module instead of a motor controller.  It is best to connect M+ and M- as shown in order to assure expected motor direction based on drawing.

Figure 4: Electrical hookup - See FRC manual

Hall interface

Two hall sensors are available to provide feedback on direction of rotation. If the signal for the hall sensor 1 rises before hall sensor 2 then direction is Clockwise.

There will be 44.4 pulses per  1 revolution of the output.

Figure 5: Reading motor direction from hall output

Speed and location can be obtained from output from either hall sensor.  There will be 44.4 pulses per 1 revolution of the output.  A pullup resistor of 1Kohm is required at each hall output (See drawing)

Motor Mounting Option 1

(Minimum Machining – ie handtools)

Figure 6:  Motor mounting with minimal machining

Motor Mounting Option 2

(Medium Manufacturing – ie drill press)

The detail described in this section is best fabricated with wood, UHMW, or similar plastic material and represents a recommended minimum size.  It is suggested to use a drill press to assure hole precision and to drill the large motor pockets with a 1-1/8” (28mm) Forstner bit.  This bit is available at most hardware stores but is typically not found in Forstner bit kits.  It is a worthwhile purchase as it is also useful for drilling bearing holes in softer materials.

Figure 7: Motor mounting option #2

Figure 8: Forstner bit - 1-1/8" (28mm) is usually not a standard size

Figure 9: Fabricated part using UHMW, hook and loop straps, etc

Motor Mounting option 3

(3D printed)

A design optimized for 3D printing with the FDM process can be downloaded for those that have this capability.  There are also many online resources for getting 3D printed parts made.  PLA material can be used or other higher strength material if preferred.  The figure below shows best orientation during printing to optimize strength and avoid supports.

3D print in this orientation.  No supports are needed.   Print same part for both halves

All holes and pockets for #10 bolts and nuts

Figure 14:  Mounting options

3D Printed Mount

Link to Download: https://a360.co/34Naa2s

Adapters

JE-PLG-410

Alternate download here: JE-PLG-410 and hex adapter

JE-PLG-149