Type S Automatic Load-Transfer Control Installation, Operation, and Maintenance Instructions

TROUBLESHOOTING—BASIC S CONTROL

!

CAUTION: Equipment misoperation. Do not

energize this equipment until all control settings

 

have been properly programmed and verified. Refer to the Control Programming and Operation section of this manual for programming procedures. Failure to comply can result in misoperation (unintended operation),

equipment damage, and personal injury.

G118.1

 

 

 

 

 

 

 

!

WARNING: Hazardous voltage. Solidly ground

all equipment. Failure to comply can

result in

 

death, severe personal injury, and equipment damage.

T223.2

General

This troubleshooting guide is intended to assist in localizing problems that may be encountered in the operation of the load-transfer scheme. After the problem area has been localized, general troubleshooting and circuit tracing techniques can be used to pinpoint the cause. A fundamental understanding of the basic operation is essential in carrying out these troubleshooting procedures. (See Theory of Operation section.)

Schematic diagrams, Figures 16 and 17, are used as references throughout this guide. The physical location of the various circuit components and terminals are identified in Figure 27.

Remove the Control from Service

!

DANGER: Hazardous voltage. Contact with haz-

ardous voltage will cause death or severe per-

 

sonal injury. Follow all locally approved safety procedures when working around high and low voltage lines

and equipment.

G103.3

The following warning only applies to controls equipped with the Fault Block Accessory:

!

WARNING: Hazardous Voltage. De-energize

switchgear before attempting to disconnect con-

 

trol cable from control. Failure to do so may result in contact with high voltage pulse (300V peak) from the CT protection circuit. Failure to de-energize switchgear can result in contact with high voltage, which will cause

death or severe personal injury.

G124.0

1.De-energize Source I and Source II voltage.

2.Disconnect cables from the control.

Basic Troubleshooting

A quick check of the basic transfer operation while the control is in service can be made using the following procedure:

Source I or Source II Preferred Operation

1.Set CONTROL MODE switch (S5) to TEST. This wilI remove the control from service and allow it to operate without operating the high-voltage transfer switches.

2.Check LATCH RELAY STATUS TEST terminals (T-1, T-2) to ground (T-3). 120 Vac at T-1 indicates the con- trol is in Source I mode; 120 Vac at T-2 indicates the control is in Source II mode. Check if this agrees with the SOURCE PREFERENCE switch setting.

3.Remove preferred source voltage by unscrewing one of the phase fuses from the applicable source. The PREFERRED TO ALTERNATE TIMER will start.

4.When the timer runs out, the latch relay (R1) will transfer; indicated by a transfer of the 120 Vac signal at the test terminals.

5.Replace the removed fuse to re-energize the pre- ferred source. The ALTERNATE TO PREFERRED TIMER will start.

IMPORTANT: If Control Mode Switch S5 is placed in the “Normal” position, the S-control will place the high- voltage transfer switches into the configuration that is currently selected by the Source Preference Switch S4. This may result in an unintended transfer. Make sure the desired state of the high-voltage transfer switches match the setting of S4 before returning S5 to the “Normal” position.

6.When the timer runs out, the latch relay (R1) will transfer back to its original operating position.

7.Return the CONTROL MODE switch (S5) to NOR- MAL to return the control to service.

20