Test & Measurement
Test and Measurement devices that require compact, powerful motors are using PMW’s brushed pancake motors in demanding applications. Printed armature motors are ideal for applications such as these, since their design offers inherently high torque, rapid acceleration and deceleration, zero cogging and precise bi-directional control.
Their slim packaging means that motors can fit neatly into universal material tensile testing machines and metallurgical sample polishing devices for example, plus rotary turntables for non-contact laser coordinate measurement machines.
Application: Material Testing Machine
Several manufacturers of material testing machines use PMW’s motors. One example is the robust G19/9T motor that precisely controls the tensile and fatigue testing offered in these systems. This brushed pancake motor has zero cogging to ensure extremely smooth movement of the sample holder crossheads, since a motor with any cogging or torque ripple would have this jerkiness amplified through the drive train.
The motor features a built-in tachometer for precise motor control feedback. The motor can therefore be controlled through a complex cycle of rapid acceleration, deceleration, reverse and repeat, needed in fatigue testing. This type of motor is very suitable for this motion profile, due to the very low moment of inertia of the motor armature.
Application: Turntable for Coordinate Measurement Machine
A higher powered GN9T motor is used in the drive train to rotate the sample turntable. Typical samples for measurement are aerospace turbine blades.
The requirement was for a very low profile servo motor with internal tachometer for speed feedback. The PMW GN9T brushed pancake motor with tacho feedback was chosen.
The primary reason is the overall height of the motor is sufficiently low to fit in the base plate of the turntable. Secondly, the GN9T motor uses an iron-free armature for zero cogging and no torque ripple under load, so that the motion is extremely smooth, ensuring angular precision of the workpiece.
The motor is coupled to a zero-backlash strainwave gearbox, for precision angular motion. As there is a high ratio reduction gearbox between motor and turntable, even the slightest ripple in the torque would be amplified. This is eliminated with the GN9T motor.