GE Industrial Solutions PowerVac with ML-18 or ML-18H Mechanism - Manual (Page 19)

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SECTION 12—Timing
Timing and speed checks are optional and also depend on the
level of maintenance performed. Generally these tests are not
required for normal maintenance. If a new mechanism has
been installed or extensive repair, replacement or major
disassembly has been performed, it is recommended that
these tests be performed.
To determine contact velocity, a travel recorder and
oscillograph are required. Optional travel recorders can be
obtained through your local GE Sales Office by ordering part
number 0144D1235G001. A typical travel trace and
interpretation are shown in Figure 12.
Timing may be checked by monitoring control circuit voltage
and using no more than six volts DC and one ampere through
the vacuum interrupter contact to indicate closed or open
condition. Typical time ranges vary with coil voltage, but
nominal values are:
Initiation of trip signal to contact parting
32-45 Milliseconds( 5 Cycle)
25-30 Milliseconds (3 Cycle)
2 Milliseconds maximum pole spread
Initiation of close signal to contact closing
35-75 Milliseconds
2 Milliseconds maximum pole spread
Trip-free operation maybe checked by applying a
simultaneous close and trip signal, and a minimum re-close
operation may be checked by tripping a charged breaker open
while maintaining a close signal.
Instantaneous re-close time* 85-150 Milliseconds.
*Time from application of trip signal until breaker contacts
re-close.
Figure 12 Sample operating speed graphs