Howard HI-110 Network Transformer - Manual (Page 4)

Document 2.4.128, Revision 2
August, 2012
4
Network Transformer Instruction Manual
SECTION 5: OPERATION OF SWITCHING AND PROTECTIVE DEVICES ..........................................................14
Tap Changer .....................................................................................................................................................15
Series/Multiple or Delta/Wye Switch .............................................................................................................15
Primary Disconnect and Grounding Switch Computer Support ..................................................................... 16
Three-Position Non-Interrupting Primary Disconnect and Grounding Switch ............................................... 16
Three-Position Mag-Break Primary Disconnect and Grounding Switch......................................................... 16
Sequential Grounding Provisions ..................................................................................................................... 17
Phase Sequence Identification Provisions ..................................................................................................... 17
Network Protector ............................................................................................................................................. 17
Other Switching and Protective Devices .......................................................................................................... 17
SECTION 6: ACCESSORIES
...............................................................................................................................18
Diagrammatic Nameplate ................................................................................................................................18
Fluid Level Gauge .............................................................................................................................................18
Fluid Temperature Gauge ................................................................................................................................18
Filler Plug and Upper Filter Press Connection .................................................................................................18
Combination Drain and Bottom Filter Valve ....................................................................................................18
Terminal Chamber Vent and Level Plug ...........................................................................................................18
Air Test Provision ...............................................................................................................................................19
Automatic Pressure Relief Valve and Pressure Relief Device .......................................................................19
Primary Entrance ..............................................................................................................................................19
High-Voltage Bushings .....................................................................................................................................19
Secondary Bushings .........................................................................................................................................20
Current Transformers ........................................................................................................................................20
Other Accessory Devices ..................................................................................................................................20
SECTION 7: MAINTENANCE
..............................................................................................................................21
Periodic Inspection............................................................................................................................................ 21
Inspection and Maintenance Checklist ........................................................................................................... 21
Electrical Testing ...............................................................................................................................................22
Exterior Paint Finish ..........................................................................................................................................23
Fluid Leaks ........................................................................................................................................................23
Audible Sound Level..........................................................................................................................................23
Other Accessory Devices .................................................................................................................................. 24
Sampling and Testing the Fluid ....................................................................................................................... 24
Filtering the Fluid .............................................................................................................................................. 24
Removing or Lowering the Fluid ....................................................................................................................... 24
Filling with Fluid ................................................................................................................................................ 24
Opening the Transformer Tank ........................................................................................................................25
Torque Guidelines .............................................................................................................................................25
Additional Maintenance Instructions .............................................................................................................. 27
Repair Parts ...................................................................................................................................................... 27
Warranty Claims ............................................................................................................................................... 27
TABLES
Table 1: Mag-Break Primary Switch Operation ............................................................................................... 16
Table 2: Sequential Grounding Switch Operation ........................................................................................... 17
Table 3: Torque Guidelines for External Cabinet Fasteners ...........................................................................26
Table 4: Torque Guidelines for External Bushing Mounting Hardware ..........................................................26
Table 5: Torque Guidelines for External Bushing Terminal Connections .......................................................26
Table 6: Torque Guidelines for Accessories ..................................................................................................... 27