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    S&C Instruction Sheet 663-590

Table 2

Table 2.  Inspection Procedures for Pad-Mounted Gear Equipped with AT-12 Source-Transfer Control

Item

Procedures

Voltage-sensor signal 

adjustments and 

measurements

1 .  Place the MANUAL/AUTOMATIC operation selector switch in the 

Manual position, and decouple both operators from their 

associated Mini-Rupter Switches . (Switching operations will result in temporary service interruptions if the operators are coupled) .

2 .  Measure the voltage-sensor signal for each phase of the preferred source and alternate source using a voltmeter having an input 

impedance of at least 5000 ohms per volt .

3 .  If the measured voltage differs from 2 .5 Volts, “scrub” the associated potentiometer by rotating the adjustment screw back and 

forth 10 to 12 times . Then, adjust the setting to obtain a 2 .5-Volt reading . (Note that a 2 .5-Volt voltage-sensor signal is appropriate 

only when the system is at nominal voltage . If the system voltage is higher or lower than the nominal voltage; the required 

voltage-sensor signal is 2 .5 volts × actual system voltage ÷ nominal system voltage .)

Switch operators

1 .  With the MANUAL/AUTOMATIC operation selector switch in the 

Manual position, open the preferred-source operator by 

pressing the appropriate OPEN pushbutton . After opening, the operator should recharge in less than 25 seconds .

2 .  Close the alternate-source operator by pressing the appropriate CLOSE pushbutton . This operator should also recharge in 

less than 25 seconds .

3 .  Return both operators to their original positions .

Time delay on loss of 

source and return of 

source (“62P,” “62A,” and 

“2P” Timers)

1 .  Place the MANUAL/AUTOMATIC operation selector switch in the 

Automatic position and note the position of the AUTOMATIC/

HOLD RETURN selector switch .

2 .  If the AT-12 control is in the 

Automatic Return mode:

a .  Simulate a prolonged loss of preferred-source voltage by pressing and holding in the SIMULATE-LOSS-OF-SOURCE test 

switch for the preferred source . Verify the time to initiate transfer is within ±20% of the setting on the “62P” timer . Also confirm 

the source voltage lamp for the preferred source extinguishes .

b .  Now, release the test switch to simulate a return of the preferred-source voltage . Verify the time to initiate back transfer is within 

±20% of the setting on the “2P” timer . Confirm the source voltage lamp for the preferred source relights .

3 .  If the AT-12 control is in the 

Hold Return mode:

a .  Simulate a prolonged loss of preferred-source voltage by pressing and holding in the SIMULATE-LOSS-OF-SOURCE test 

switch for the preferred source . Verify the time to initiate transfer is within ±20% of the setting on the “62P” timer . Also confirm 

the source voltage lamp for the preferred source extinguishes .

b .  Release the test switch to simulate a return of the preferred-source voltage, and wait a sufficient length of time to verify back 

transfer does not occur . Confirm the source voltage lamp for the preferred source relights .

c .  Now, simulate a loss of alternate-source voltage by pressing and holding in the SIMULATE-LOSS-OF-SOURCE test switch for 

the alternate source . Verify the time to initiate back transfer if within ±20% of the setting on the “62A” timer . Confirm the source 

voltage lamp for the alternate source extinguishes, and then release the test switch .

TABLE CONTINUED 

Summary of Contents for PMH

Page 1: ...Retain this Instruction Sheet 2 Proper Application 2 Warranty 2 Warranty Qualifications 2 Safety Information Understanding Safety Alert Messages 3 Following Safety Instructions 3 Replacement Instructi...

Page 2: ...is a permanent part of your S C Source Transfer PMH Pad Mounted gear Designate a location where you can easily retrieve and refer to it Proper Application CAUTION The equipment in this publication mu...

Page 3: ...commended recautions are not followed NOTICE NOTICE identifies important procedures or requirements that can result in product or property damage if instructions are not followed Following Safety Inst...

Page 4: ...y to authorized persons so that the key interlock scheme will not be comprised Key interlocks are not security locks and are not substi tutes for padlocks 5 Opening Doors Do not apply any undue force...

Page 5: ...ctory and in the field These settings are entered into the control by means of a keypad on the front panel and may be reviewed via a liquid crystal display CAUTION When following the inspection proced...

Page 6: ...ile still in the text menu press the Next item key one more time The Enable Test Keys item will appear on the display Press the Change key Then select On mode by pressing the Enter key The test keys a...

Page 7: ...hen press the Next item key The date time and event ID for the last control operation will appear on the display Confirm the event ID on the display is 218 enter manual software Press the key to view...

Page 8: ...loss of source and return of source 62P 62A and 2P Timers 1 Place the MANUAL AUTOMATIC operation selector switch in the Automatic position and note the position of the AUTOMATIC HOLD RETURN selector...

Page 9: ...ch in the Manual position and press the OVERCURRENT LOCKOUT RESET pushbutton to cancel the lockout condition Confirm the OVERCURRENT LOCKOUT lamp extinguishes Then close the preferred source operator...

Page 10: ...barriers are left in the slide in position for extended periods of time there is the possibility of corona discharge to the barriers Prolongedexposuretocoronadischargemaydamage the barriers and resul...

Page 11: ...face imperfections can be burnished out Clean the blades and apply a thin layer of lubricant as necessary b Clean rotating hinge contacts and apply a thin layer of lubricant as necessary c Check conta...

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