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Fig. 12 

 
9.4 Surge Arresters 

The function of a surge arrester is to intercept and divert 
to ground various over voltage transients (such as lightning 
surges)  which  occur  on  the  distribution  system.  Surge 
arresters can be installed in the Air Terminal Chambers 

The arresters must be disconnected whenever high potential 
or induced potential tests are made on transformers with 
arresters. 

9.5 Pressure Relief Device 

The  standard  pressure  relief  device,  located  on  the  tank 
above  the  liquid  level,  relieves  excessive  internal  tank 
pressure  and  reseals  at  a  lower  positive  pressure.  The 
pressure  relief  device  is  manually  operated  by  grasping 
the end-cap (or ring if provided) and slowly pulling the cap 
away from the tank until pressure is relieved. 

Pressure relief diaphragm (when provided) is located on 
tank top hand hole cover.  

9.6 Thermometer 

When  supplied,  a  thermometer  indicates  the  liquid 
temperature  near  the  top  of  the  tank.  The  temperature 
sensitive element is mounted in a leakproof well, permitting 
removal  of  the  thermometer  without  lowering  the  liquid 
level. The device is furnished with an additional pointer, red 
in  color,  to  show  the  highest  temperature  attained  since 
last reset. 

9.7 Liquid Level Gauge 

When supplied, a liquid level gauge is located in the right 
side of the front panel or segment 1 to indicate the variation 
from the 25 degree C liquid level. 

9.8 Pressure-Vacuum Gauge 

When  supplied,  a  pressure-vacuum  gauge  is  located  in 
the right side of the front panel or segment 1. This gauge 
indicates whether the gas space in the tank is under positive 
or negative pressure. 

9.9 Nameplate 

A  nameplate  is  supplied  on  each  transformer  according 
to  ANSI  standard  C57.12.00-1980,  Section  5.12.  Refer 
to  the  nameplate  for  transformer  ratings  and  for  proper 
connections of the transformer to the system. No internal 
connections should be made inside the transformer other 
than those shown on the nameplate. 

9.10 Control Cabinet 

 

WARNING: 

THE  CONTROL  CABINET  CONTAINS 

CONTROL  VOLTAGE  AND  ELECTRICAL  POWER 
FOR  COOLING  FAN  OPERATION.  ENSURE THAT 
CABINET  IS  ADEQUATELY  GROUNDED  AND 
ALWAYS  REMOVE  THE  CONTROL  CABINET 
POWER SUPPLY PRIOR TO PERFORMING WORK 
INSIDE THE CONTROL CABINET EQUIPMENT OR 
CONNECTED ACCESSORIES. FAILURE TO DO SO 
COULD RESULT IN SEVERE PERSONAL INJURY, 
DEATH OR PROPERTY DAMAGE.

 
Refer  to  wiring  diagram  for  electrical  circuits  inside  the 
control  cabinet.  Use  an  indicating  light  type  device  when 
checking an alarm switch. Failure to do so could result in 
damage. Inspect cords or conduits for wear and evidence 
of  damage.  Repair  or  replace  any  damaged  cords  or 
conduits.

The cooling fan motor electrical data can be found on 
the motor nameplate or the wiring diagram. The controls 
for the fan motor are contained in the control cabinet 
mounted on the transformer. 

The “Manual-Auto” switch determines the mode of 
operation. When the switch is in the “Manual” position, the 
fans will operate continuously. When the switch is in the 
“Auto” position, the fans will be automatically controlled by 
the thermal devices mounted on the transformer. 

When specified the “Manual-Off-Auto” type fans switch is 
provided. When the switch is in the “Manual” position, the 
fans will operate continuously. When the switch is in the 
“Off” position, the fans will not operate. When the switch 
is in the “Auto” position, the fans will be automatically 
controlled by the thermal devices mounted on the 
transformer. 

The fan motors are normally provided with thermal 
overload protection. However, if the fans are designed for 
hazardous locations, protection may be provided in the 
control cabinet. Refer to the wiring diagram for specifics.

The fan motors have permanently sealed ball bearings 
and require no additional lubrication. When assembled, 
fan motors are provided with drain plugs installed for 
proper orientation. Visually inspect plug placement to 
ensure that plugs are correct per fan manufacturer’s 
recommendations.   

Page 6

Summary of Contents for ILUJ000004-BLE

Page 1: ... TO INSTALL MAINTAIN OPERATE OR SERVICE THE TRANSFORMER FAILURE TO FOLLOW INSTRUCTIONS CAN CAUSE SEVERE INJURY DEATH OR PROPERTY DAMAGE Keep this Instruction Book available to those responsible for the installation maintenance operation and service of the transformer Safety as defined in this Instruction Book involves two conditions Personal injury 1 Product or property damage 2 SEE IMPORTANT DISC...

Page 2: ...et wrench as used widely in the utility industry 4 0 EXTERNAL INSPECTION WARNING THE OIL MUST BE AT THE PROPER LEVEL 25 C LEVEL BEFORE VOLTAGE IS APPLIED TO THE TRANSFORMER FAILURE TO MAINTAIN THE PROPER OIL LEVEL CAN CAUSE SEVERE PERSONAL INJURY DEATH OR SUBSTANTIAL PROPERTY DAMAGE The oil level should be checked by inspecting the liquid level gauge Any unit which does not have the proper oil lev...

Page 3: ...egrees as a greater tilt will cause deviations in liquid level near live parts pressure relief devices or other accessories specifically located at or near the 25 degree C liquid level CAUTION DEVIATIONS FROM SPECIFIED OIL LEVEL CAN INCREASE THE POSSIBILITY OF A DISRUPTIVE FAILURE Unit substation transformers must be adequately anchored and secured to the pad When seismic conditions are specified ...

Page 4: ...ergized transformer make sure that any protective or insulating barriers are in place the air terminal chamber is completely closed and all locking provisions are properly installed The following procedure should be used to assure air terminal chamber security A Close the left door and secure it in place with the captive bolts supplied pentahead or hexhead B Close the right door and secure it in p...

Page 5: ...cated on the front panel of the transformer refer to Fig 11 A De energize the transformer B Back out the locking screw until it is clear of the locking hole C Turn the handle to the desired tap position D Tighten the locking screw to minimize the possibility of unintentional movement Some large size units are furnished with a power transformer tap changer drive which requires pulling of a locking ...

Page 6: ...e the transformer other than those shown on the nameplate 9 10 Control Cabinet WARNING THE CONTROL CABINET CONTAINS CONTROL VOLTAGE AND ELECTRICAL POWER FOR COOLING FAN OPERATION ENSURE THAT CABINET IS ADEQUATELY GROUNDED AND ALWAYS REMOVE THE CONTROL CABINET POWER SUPPLY PRIOR TO PERFORMING WORK INSIDE THE CONTROL CABINET EQUIPMENT OR CONNECTED ACCESSORIES FAILURE TO DO SO COULD RESULT IN SEVERE ...

Page 7: ...e overload Planned overloading should be in accordance with the ANSI Loading Guide C57 91 When adding oil to the transformer the owner should take the necessary precautions so that PCB contamination is not introduced WARNING OIL SAMPLES SHOULD BE TAKEN FROM THE TRANSFORMER ONLY AFTER DE ENERGIZING AND MANUALLY VENTING THE TRANSFORMER FAILURE TO DO SO CAN CAUSE SEVERE INJURY DEATH OR PROPERTY DAMAG...

Page 8: ...formers THIS INFORMATION SHOULD NOT BE CONSIDERED TO BE ALL INCLUSIVE OR COVERING ALL CONTINGENCIES NO WARRANTIES EXPRESS OR IMPLIED INCLUDING WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSEORMERCHANTABILITY ORWARRANTIESARISINGFROMCOURSEOFDEALINGORUSAGEOFTRADE ARE MADE REGARDING THE INFORMATION RECOMMENDATIONS DESCRIPTIONS AND SAFETY NOTATIONS CONTAINED HEREIN In no event will ABB be responsible to...

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