Howard Network Transformers User Manual

Page 6

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Optional Features and Accessories

The following optional features and accessories are avail-

able. Check with the factory for the availability of other

features and accessories not listed.

• Series-multiple high-voltage winding

• Delta-wye connection

• Special high-voltage taps

• Special low-loss high efficiency designs

• Design optimization to lowest total owning cost

• 50 Hertz operating frequency

• Special impedance

• Special sound level

• Special phase relationship

• Special BIL level

• Over excitation capability

• 65° C average temperature rise

• Special ambient temperature

• Operation at altitudes above 3300 feet

• Copper windings

• Core ground test point located inside tank accessible

from bolted handhole

• Electrostatic shields

• Optional tank features and accessories

− Special hardware

− Welded handhole cover

− Additional bolted or welded hand-hole

− Special tank design pressure (up to 15 psig)

− Ground connectors

− Special tank dimensions

− Tank undercoating

− Omit pressure-relief valve

• Optional gauges and fittings

− Dial-type magnetic liquid-level gauge (with alarm


− Dial-type thermometer (with alarm contacts)

− Pressure-vacuum gauge (with or without alarm


− Automatic pressure-relief device (with or without

alarm contacts)

− Drain valve with liquid sampling valve

− Additional drain valve on tank or switch chamber

− Spare gaskets for secondary throat, bolted hand-

holes, high-voltage terminal chamber, and switch


− Sight gauge for high-voltage terminal chamber

− Other options (check with factory)

• Optional high-voltage switch features and accessories

− Interrupting switch or other special switches

− Provisions for phase sequence identification

(phasing tubes)

− Phase sequence indication (sequential ground-

ing), including 3 internal grounding contacts,

5-position switch to indicate phase when switch is

moved from transformer positions to ground posi-


− Additional electrical interlocks

− Viewing windows for observation of switch blades

(with hinged protective cover)

• Optional high-voltage entrance features and accessories

− Single-conductor or multi-conductor wiping

sleeves, or pothead entrance

− Six universal bushing wells for loop feed with or

without loadbreak inserts (HV switch must be


− Three integral loadbreak bushings

− Three non-Ioadbreak bushings

− Six non-Ioadbreak bushings for loop feed (HV

switch must be omitted)

− Six integral loadbreak bushings for loop feed (HV

switch must be omitted)

− Three molded bushings mounted on front of

terminal chamber in lieu of the standard wiping


− Potheads, one 3-conductor or three 1-conductor,

instead of the standard terminal chamber

− Bottom entrance of HV cable, including wiping


− Packing gland or stuffing box

− Phase separation barriers in compartment (when

switch is omitted)

− Dielectric fluid or compound for terminal chamber

• Optional low-voltage air terminations

− Welded low-voltage bushings

− Fully insulated low-voltage neutral bushing

− Other low-voltage termination options (check with


• Optional network protector provisions (check with factory)

• Optional dielectric fluids

− Silicone fluid

− FR3 natural ester-based fluid

Network Transformer


Copyright © 2010 Howard Industries, Inc.


Howard Industries, Inc.

Laurel, MS 39440

Catalog Section 94-10

Network Transformers

Issued: April 9, 2010