S&C ELECTRIC COMPANY
s
INSTRUCTION SHEET
663-503
Page 29 of 35
August 14, 1995
Preliminary Tryout Before Gear Is
Energized—Optional
To expedite full service once high voltage is available, the
user may wish to perform a preliminary checkout of the
Micro-AT Source-Transfer Control before the gear is ener-
gized. For this purpose an S&C Test Accessory, Catalog
Number TA-1316, is available to permit checkout of the
source-transfer operation using an external single-phase
120-volt ac source.
If a preliminary checkout is to be performed, special
instructions must be followed to ensure correct operation
of the Micro-AT control. These instructions are set forth in
S&C Instruction Sheet 515-510, furnished with the test
accessory. The programming and testing described under
“FIELD ADJUSTMENT AND PROGRAMMING” and
“OPERATIONAL TESTING” in S&C Instruction Sheet
515-500 can be completed during the preliminary
checkout.
When the test accessory is used, the control power
available to supply the charging motors of the stored-
energy operators and to maintain the charge on the sole-
noid-tripping capacitors is less than that available during
normal three-phase operation.
As a result, the time
required for the motors to charge the stored-energy oper-
ators will be longer than normal. Furthermore, it may
take as long as two minutes after the stored-energy oper-
ators are charged for the solenoid-tripping capacitors to
become fully charged.
Therefore, wait at least two min-
utes after the stored-energy operators are charged before
initiating a transfer operation.
APPENDIX A
Dielectric Testing
When high-voltage dielectric tests are to be performed on
S&C Source-Transfer PMH Pad-Mounted Gear, special
precautions should be taken to prevent damage to the
voltage sensors and voltage limiters. Refer to S&C Instruc-
tion Sheet 591-500.
Ratings for S&C Mini-Rupter Switches
Complete ratings for Mini-Rupters as applied in S&C
Source-Transfer PMH Pad-Mounted Gear are shown in the
table below. In addition to the load-dropping ratings
shown, Mini-Rupter is capable of interrupting transformer
magnetizing currents associated with the applicable
loads, as well as line-charging and cable-charging currents
typical for distribution systems of these voltage ratings.
For applications on systems rated higher than 7.2 kv and
involving load current with high harmonic content (such
as rectifier load currents), refer to the nearest S&C Sales
Office. The two-time duty-cycle fault-closing ratings
shown for Mini-Rupters define the ability to close the
Mini-Rupter twice against a three-phase fault with asym-
metrical current in at least one phase equal to the rated
value, with the switch remaining operable and able to
carry and interrupt rated current.
APPENDIX C
APPENDIX B
RATINGS FOR S&C MINI-RUPTER SWITCHES
Kv
Amperes, Rms
Nom.
Max
BIL
Cont.
Live Switching
Momentary
(Asym.)
1-Second
(Sym.)
Load Splitting
(Parallel or
Loop Switching)
Load
Dropping
Duty-Cycle
Fault-Closing,
Two-Time (Asym.)
14.4
25
17.0
29
95
125
600
600
600
600
600
400
22 400
22 400
22 400
22 400
14 000
14 000
14,000 amperes rms symmetrical, 35,000 amperes peak.
