Modern Assembly

This station is used to do a resistance and inductance check for every motor that is assembled into a drive unit. These values are used to insure that all of the motors are within a very tight tolerance band. The computer will reject any units that do not meet the tolerance specified.

If a unit is rejected at any point on the line, the computer system locks that unit out and does not allow it to be used at any other stations on the line until it has been reworked. This prevents a bad unit from continuing through the assembly process. 

This station is used for three different parts of the assembly. This first is a burn in of the unit. The units are run until they reach a specified no load current. This burn in helps with the seals as well as making sure that there are no major defects in the gears. The second test is to make sure that the unit is air tight. A pressure tested is used to pressurize the unit and make sure that there are no leaks above a specified limit. This test is to make sure that the units will not leak grease when they are in the field. The final step at this station is to fill the unit with grease. A scale is used along with an automated process to insure that a specific amount of grease is used in each unit. If there is not enough grease in the unit, it can cause excessive wear in the gearing. If there is too much grease in the unit, the efficiency of the unit will decrease. 

This station is used to zero one of the two encoders that are in this drive unit. The encoder is used to measure the speed of the motor as well as for motor feedback used to control the Brushless DC motor. When an operator is zeroing an encoder the screen displays red and green lights for each of the channels of the encoder. When all three of the lights are green, the operator knows the encoder is aligned correctly. Once the encoder is aligned, the unit can be powered and tested. 

This is a picture of the end of line test stand. The end of line is divided into two sections. The first section is used to test the drive unit at different speeds and torques to make sure that every unit meets a specific loading profile defined by our customer. The second test is used to check that the motor velocity constant. The motor velocity constant is used to make sure that there is very high level of consistency for every drive unit we make. If the unit meets all the criteria for every portion of the test then all the boxes on the screen turn green and a message is displayed that the unit passed.  If the unit fails for any reason, there is an error message informing the operator of the failure so that the unit can be properly dispositioned.