10
1.3
Timer Control
1.3.1
The timer system will have the following parameters:
Range:
0-999.999 seconds (Quartz locked)
Resolution:
0.001 seconds
Accuracy:
Contact mode ± 2ms
Current mode ± 3ms for test currents 20-40% on each range
Current mode +3ms or -1ms for test currents 40-100% on each range
NOTE:
Timing results obtained with test currents below 20% of the selected
ammeter range, and on measured times of 19ms and below, are of
doubtful accuracy and should be ignored.
1.3.2
The timer system has three modes of operation which are as follows:
a.
Timing relays with normally closed contacts. (N/C)
b.
Timing relays with normally open contacts. (N/O)
c.
Timing circuit breakers both electromagnetic and thermal types where no
auxiliary contacts are available. (
I
)
1.3.3
The external contacts may be voltage free or may have a DC voltage applied
(220V DC maximum).
NOTE:
See
Section 2
for
connection procedure for live contacts.
1.3.4
In the
I
position an additional control selector switch is provided to enable the timer
system to operate either from A, B or C phase injected current.
