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Figure 26. Sample Operating Speed Graphs
Timing may be checked by monitoring control
circuit voltage and using no more than six volts
DC and one ampere through the vacuum inter-
rupter contact to indicate closed or open condi-
tion. Typical time ranges vary with coil volt-
age, but nominal values are:
Initiation of trip signal to contact parting
32-45 milli-seconds
2 milli-seconds maximum pole spread
Initiation of close signal to contact closing
35-75 milli-seconds
2 milli-seconds maximum pole spread.
Trip-free operation may be checked by applying
a simultaneous close and trip signal, and a mini-
mum reclose operation may be checked by trip-
ping a charged breaker open while maintaining
a close signal.
Instantaneous reclose time 85-150 milliseconds.
*Time from application of trip signal until
breaker contacts reclose.
Courtesy of NationalSwitchgear.com
PowerVac
Chapter 10. Maintenance
The opening speed is modified by moving the
speed adjusting nuts on the opening spring as-
semblies. A change in the opening speed af-
fects the closing speed Reference Figure 27.
The operating speeds for 5 cycle breakers
with the MOC are as follows:
Operation
Feet Per Second
Open
6.5 normal, 4.5 minimum
Close
2.6 nominal, 4.2 maximum
Figure 27. Opening Speed Adjustment
1. Lock Nuts
2. Opening Spring
3. Outer Bell Crank
4. Primary Cross Shaft
33
5kV Vertical Lift
®
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