BECKWITH ELECTRIC M?3311A, Instruction Book

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4–86
M‑3311A Instruction Book
CCM (CLOSE CIRCUIT MONITOR)
Figure 4-56 displays the settings for the CCM
function. The settings for the CCM #2 Close Circuit
Monitor are the same as the CCM #1.
The CCM inputs are provided for monitoring the
continuity of the close circuits. The inputs can be
used for nominal close coil voltages of 24 V dc to
250 V dc. Close circuit monitoring is performed in
the active breaker status only. Both the DC supply
and continuity for the close circuit is monitored. If
a close coil is detected as being open for the time
delay then transfers are blocked.
The M-3311A Close Coil Monitor will illuminate the
appropriate alarm LED on the unit front panel when
all of the following conditions exist:
• The M-3311A CCM is connected to the
target close coil circuit.
• An open condition has been detected in
the close coil circuit for the duration of the
Time Delay.
The close coil circuit open detection circuit will il -
luminate the alarm LED even when the M-3311A
is not physically connected to the close coil circuit.
When the M-3311A is not connected to the close
coil circuit, then the appropriate CCM alarm LED on
the unit front panel should be labeled as necessary
to identify the alarm as not valid.
This function is blocked when the breaker is open,
as indicated by 52b Contact Input (IN1). If the CCM
is monitoring a lockout relay, a 86 Contact Input
(INx) should be used to block when the lockout relay
is tripped. This function is also blocked when any
output contact is closed.
The output of the Close Circuit Monitoring function
can be programmed as an alarm to alert mainte-
nance personnel.
CCM Connection Considerations
— External
connections for the Close Circuit Monitoring function are
shown in Figures 4-57, 4-58 and Figures 5-8 through
5-28.
The default Close Circuit Monitor input voltage is
250 V dc. See Section 5.5, Circuit Board Switches
and Jumpers , (Table 5-4 for CCM#1, Table 5-6 for
CCM#2) for other available close circuit input volt -
age selections.
Beckwith Electric Co., Inc. recommends that the
M-3311A CCM circuit be connected directly to the
close coil, bypassing the anti-pump “Y” relay por-
tion of the close circuit as illustrated in Figure 4-57.
The type of anti-pump “Y” relay that is often found
within the close coil circuit is generally a high imped -
ance type, such as an IDEC RR Series Power Relay.
The relay coil resistance is high (approximately 8.5
to 10K Ohms), and it’s rated pickup current is 11 to
13 mA, ± 15% at 20° C. However, the relay’s dropout
voltage is approximately 10 to 15% of rated 110 V
dc voltage. Therefore, the anti-pump relay may be
held up and would not drop out until the leakage
current is reduced to approximately 2 mA.
▲
CAUTION : Connecting the M-3311A Close Coil
Monitor (CCM) in parallel with other relay CCMs in
the close coil circuit where the anti-pump “Y” relay
is not bypassed may not provide reliable breaker
closing operations.
If the close coil circuit configuration does not sup-
port connecting the CCM directly to the close coil
(Figure 4-58), then Beckwith Electric Co., Inc. does
not recommend connecting the M-3311A CCM in
parallel with other relay CCMs. If two or more CCMs
are connected to the close coil circuit, there is a high
probability that the anti-pump “Y” coil will not drop
out. Therefore, only one CCM, either a M-3311A or
other relay should be used in the close coil circuit to
provide reliable breaker closing operation.
Enable/Disable
— The top right corner of the dis-
play includes a command button that will disable
or enable the function. This selection allows the
CCM #1 (Close Circuit Monitor) to be disabled (or
enabled) independent from the CCM #2.
Time Delay — A Time Delay can be applied to delay
the CCM (Close Circuit Monitor) function output.
Dropout Time Delay
— A Time Delay can be ap-
plied to delay the reset of the CCM (Close Circuit
Monitor) function output.
I/O Selection — I/O Selection allows any input
to be selected to block the CCM . The CCM #1(2)
Function can also be used to activate a selected
output when it times out.
Save/Cancel — The Save selection saves the CCM
Function Dialog Screen settings either to an open
file or to the target M-3311A. Cancel, returns the
user to the previous open screen.