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GE Zenith Controls
13
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Entelli-Switch 250 Operation and Maintenance Manual (71
R
-2000)
Accessory Definitions
(cont’d)
Notes: - If S2 Frequency is less than S1 Frequency,
display will show a series of (- - - - -…..) symbols.
- If S2 Frequency is greater than S1 Frequency,
display will show a series of (+++++…..) symbols.
- Each (-) or (+) symbol represents 10 electrical
degrees out of phase. A maximum of 18 symbols
(180 electrical degrees) can be monitored.
- The number of (-) or (+) symbols decrease
as the two sources approach synchronism
and increase as the two sources drift out
of synchronism.
- If S1 and S2 Frequencies are identical, the
display will show a series of alternating
- - - -
symbols (++++…) which also indicate the
approximate out of phase degrees
In the event that the Sources do not come within 7
electrical degrees of each other within 60 seconds, the
unit will display the message: SYNCH CHECKING and
will allow the user to BYPASS. If the BYPASS button is
pressed, the unit will display the message: WARNING
MAY CAUSE DAMAGE TO THE LOAD
. Pressing XFR
will actually bypass the R50. Since R50 is a passive device,
the length of time it takes to reach Synchronism is de-
pendent on the frequency difference between the two
Sources. Source 1 is usually a Utility and the frequency
is not within the control of the consumer. Source 2
needs to be adjusted to create an adequate difference
in order for the transfer to happen a timely fashion.
Note: For optimum performance, Source 2
Generator should be adjusted a Maximum of
2 Hertz above or below the Utility frequency,
minimum of 0.1 Hertz. (58 to 59.9) or
(60.1 to 62) Hertz. Adjustment of Generator
to 60Hertz could cause lengthy transfer delay
.
R50 Feature can be turned ON or OFF via CFG Menu
(see page 17). Factory Default if OFF.
S5P
Auto / Semi Manual selector
In "Auto" position, retransfer to Source 1 is automatic
after the T timer has timed out. The T time delay is
bypassed if Source 2 fails.
In "Manual", retransfer to Source 1 is upon depression
of BYPASS DELAY button YEN or if Source 2 fails.
S12P
Auto / Manual Selector
In "Auto" position, the Automatic Transfer Switch
functions automatically as specified with the Switch
drawings.
In "Manual" the Automatic Transfer Switch will transfer
to either direction upon depression of Source 1 or
Source 2 transfer buttons.
Should Source 1 fail, the Generator (Source 2), will
automatically start. Once transferred in Manual, the
Switch maintains position selected even if selected
power fails.
S13P
Transfer Commit. Configured via CFG menu.
(see page 17) When this Feature is set to OFF:
The transfer Switch is not committed to transfer unless
the outage duration is longer than the timers that
precede the transfer to Source 2 position. This assumes
that the outage will be an isolated event. When this
Feature is set to ON: The transfer Switch is committed
to transfer to Source 2 position once the W timer has
begun timing, even if Source 1 power returns before
the transfer to Source 2. This is to ensure that the
transfer takes place, because one outage may be
followed by another.
S14
Test / Auto / Source 1 Selector, Door mount
SW1
Auto/Off/Start Engine control selector, Door mount
(Keyed or non-keyed operation available)
SW2
Auto / Off Engine control selector, Door mount
(Keyed or non-keyed operation available)
SW3
Source Priority Selector Switch, Door mount
Allows selection of Source 1 or Source 2 to be the Prime
Source. Transfer Switch will transfer to selected Prime
Source if that Source is available. (Keyed or non-keyed
operation available)
T
Time Delay (S1) Source 1 Stable Timer. To delay trans-
fer to Source 1 (immediate retransfer on Source 2 fail-
ure). Adjustable 0-60 minutes in 1 second increments.
Standard setting is 30 minutes. Adjust via SET menu
(see page 18)
T3/W3
Elevator Pre-Signal Auxiliary Contacts: Open 0-60
seconds prior to transfer to either direction,
re-closes after transfer.
U
(S2) Source 2 Stop Delay Timer. Allows Engine to run
unloaded after switch retransfer to Source 1. Adjustable
0-60 minutes in 1 second increments. Standard setting is
5 minutes. Adjust via SET menu (see page 18)
UMD
Universal Motor Load Disconnect Circuit: Auxiliary
Contact opens 0-60 seconds prior to transfer in either
direction, re-closes after transfer. Can be configured by
end user for Pre-transfer, Post-transfer, or both.
