Document 2.4.128, Revision 3
October, 2017
27
Network Transformer Instruction Manual
Table 6: Torque Guidelines for Accessories
Component
Nominal
Torque¹
(in-lbs)
Torque
Range
(in-lbs)
Fluid level sight glass
600
480-720
Fill plug
960
900-1020
Drain plug
960
900-1020
Drain valve
600
480-720
Automatic pressure
relief device, ¼” NPT
180
160-200
Automatic pressure
relief device, cover-
mounted
300
250-350
Ground connector
160
140-180
Additional Maintenance Instructions
These instructions are intended to be a general
guide for the maintenance of Howard secondary
network transformers, when used in typical
applications and operated in usual environments
as described in IEEE Standard C57.12.00. Although
efforts have been made to ensure accuracy and
completeness, these instructions do not address
every conceivable application or circumstance that
might be encountered.
Features and accessory devices discussed herein
may not be present in all transformers. Some
features or accessory devices may be present on a
transformer, but not discussed in these instructions.
Howard Industries does not represent that these
instructions are complete, sufficient, accurate or
useful for all circumstances.
Questions regarding installation, operation, and
maintenance (particularly when encountering
unusual or special circumstances not sufficiently
covered by these instructions) should be directed to
the Howard Industries Transformer Division.
Repair Parts
Repair parts can be ordered from the Howard
Industries Transformer Division. A description of
the part and the transformer serial number will be
required to ensure that the correct part has been
ordered.
Warranty Claims
The Howard Industries Transformer Division
should be notified immediately when problems are
discovered during the warranty period. All warranty
repairs must be made or approved by the Howard
Industries Transformer Division.
Transformer Disposal
Comply with all local, state and federal regulations when
disposing of any insulating fluid. Fluid type and volume
can be determined by referring to the transformer
nameplate. Contact Howard Industries to obtain the
appropriate fluid Safety Data Sheet (SDS). The SDS
identifies fluid composition and properties, and describes
important safety, handling and storage, ecological,
regulatory, disposal and other pertinent information.
WARNING
Improper disposal of a
transformer
could result in
personal injury or death and could be hazardous to
the environment.
Before the transformer tank can be safely cut with a
grinder or torch, any potentially explosive gasses must
be removed from the tank interior. This can be done by
first operating the pressure relief device to slowly bring
the tank interior to atmospheric pressure, removing the
transformer cover or hand-hole cover, and then completely
purging the interior with pure air or an inert gas such as
nitrogen.
¹
When checking tightness of gasketed components, the measured
torque will normally be less than the nominal torque listed in the table
above due to relaxation of the gasket material. Additional tightening
of mounting hardware may cause the component to crack or the
gasket to become over-compressed.
