Applications for Differential Phase-Shifters

Speed and Position Control Required for Finishing a Pre-Printed Web:

Speed and Position Control A pre-printed web that requires finishing (i.e. die-cutting, perforating, gluing, etc.) needs a drive system that can compensate for two errors. First the nominal length of the printed product requires a rotational speed slightly higher (0.1%) than the synchronous speed of the drive-train to provide an exact number of impressions per minute. Additionally, the drive system must advance or retard each impression to compensate for errors in their lengths.

The DR differential phase shifter meets both of these requirements.

The input shaft (N1) is driven by the line shaft and the output shaft (N2) drives a nip roll, which moves the web, with an exact ratio of 1:1. A small (low HP) motor drives the adjusting shaft (N3) at a constant speed to increase the speed of the output shaft (N2) by 0.1%:

N2 = N1 / 1.0 + N3 / 135 = N1 + 0.001 N1

N3 = 0.001 N1 x 135 = 0.135 N1

Errors in impression length are then corrected by advancing (speeding up) or retarding (slowing down) the adjustment shaft (N3) about the continuous operating speed predefined by the required impressions per minute.

The DR differential phase shifter provides the following performance advantages in this application:

Low backlash avoids impression length errors due to torque reversals.
Nominal impression length errors of +/- 1% can be corrected.
Minimum control power required.

Other Applications:

To insure proper selection, please consult the factory. If you have any questions regarding the information provided here or require more information, please call us at (800) 713-6170 or e-mail us. Our Sales and Engineering departments are ready to help you with your specific power transmission needs.