33
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.
Figure 27. Opening Speed Adjustment
1. Lock Nuts
2. Opening Spring
3. Outer Bell Crank
4. Primary Cross Shaft
PowerVac
®
5kV Vertical Lift
Chapter 10. Maintenance
Figure 26. Sample Operating Speed Graphs
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