Vanguard DigiTMR User Manual

Page 73

REV 3 DIGITMR USER’S MANUAL

4.0 GLOSSARY OF TERMS

Breaker Bounce-Back Distance

Bounce-back is the distance the breaker contact moves before the resting position after the
over-travel. Bounce-back is typically found in the close operation.

Breaker Over-Travel Distance

Over-travel is the distance the contact moves beyond the resting position. Over-travel is
typically found in the close operation.

Breaker Stroke

Circuit breaker contact stroke is the absolute distance measured from the open position to the
close position, excluding the over-travel and bounce-back distance. The DigiTMR uses a digital
transducer to measure a breaker's contact stroke, over-travel and bounce-back. The digital
transducer outputs 200 counts per linear inch of travel, therefore the resolution is accurate to
about 1/200 inch. The output resolution is ±0.01 inch on the test result report.

Unlike resistor-type transducers, the DigiTMR’s transducer needs no calibration or setup. A
user verifies the transducer’s functionality by selecting a diagnostic test for the transducer.

Breaker Velocity (Speed)

The DigiTMR, when used with a travel transducer, calculates the breaker contact velocity
through the arc zone. Users need to program the calculation points or analysis points on the
travel curve for the unit to calculate the contact velocity. Velocity calculation points are shown
as Point 1 and Point 2 under the “Speed Analysis” section of the tabulated report.

Contact Wipe

Contact wipe is the distance measured from the close position to the contacts touching or
parting positions. In the close operation, contact wipe is measured from the contacts touching
position to the final close position. In the open operation, the contact wipe is measured from
the close position to the contact break or parting position.

NOTE

Contact wipe is measured during an operation. The measurement may not be as
accurate as the measurement done using the Slow-Close Mode. It is recommended
that the Slow-Close Test be used to verify the contact wipe measurement.