MR MESSKO MPREC User manual

Pressure Relief Device
MESSKO® MPREC®
Operating Instructions
BA5789879-01 EN

© All rights reserved by Messko GmbH
Dissemination and reproduction of this document and use and disclosure of its
content are strictly prohibited unless expressly permitted.
Infringements will result in liability for compensation. All rights reserved in the event
of the granting of patents, utility models or designs.
The product may have been altered since this document was published.
We reserve the right to change the technical data, design and scope of supply.
Generally the information provided and agreements made when processing the
individual quotations and orders are binding.
The original operating instructions were written in German.

Table of contents
3BA5789879-01 EN
1 Introduction...........................................................................5
1.1 Manufacturer.................................................................................... 5
1.2 Subject to change without notice ..................................................... 5
1.3 Completeness.................................................................................. 5
1.4 Safekeeping..................................................................................... 6
1.5 Notation conventions ....................................................................... 6
1.5.1 Hazard communication system .................................................................... 6
1.5.2 Information system....................................................................................... 8
1.5.3 Instruction system ........................................................................................ 8
1.5.4 Typographic conventions ............................................................................. 9
2 Safety...................................................................................10
2.1 Intended use .................................................................................. 10
2.2 Fundamental safety instructions .................................................... 11
2.3 Personnel qualification................................................................... 12
2.4 Personal protective equipment ...................................................... 14
3 Product description............................................................16
3.1 Scope of delivery ........................................................................... 16
3.2 Pressure relief device function description .................................... 16
3.3 Design/versions ............................................................................. 17
3.3.1 Pressure relief device with standard protective cover................................ 18
3.3.2 Pressure relief device with OD protective cover ........................................ 19
3.4 Nameplate ..................................................................................... 21
4 Packaging, transport and storage ....................................22
4.1 Purpose ......................................................................................... 22
4.2 Suitability, structure and production............................................... 22
4.3 Markings ........................................................................................ 22
4.4 Transportation, receipt and handling of shipments........................ 22

Table of contents
4 BA5789879-01 EN
4.5 Storage of shipments..................................................................... 24
4.6 Further transport ............................................................................ 24
5 Mounting .............................................................................25
5.1 Mounting pressure relief device with standard protective cover .... 27
5.2 Mounting pressure relief device with OD protective cover............. 30
5.3 Electrically connecting the pressure relief device .......................... 35
5.3.1 Connecting cable screw connections......................................................... 36
5.3.2 Connecting the cable to the terminal box................................................... 38
5.3.3 Connecting the plug connector (ANSI or Westinghouse)........................... 39
6 Commissioning...................................................................41
7 Operation.............................................................................43
7.1 Pressure relief device operating state ........................................... 43
7.2 Venting the pressure relief device ................................................. 44
8 Maintenance and inspection .............................................46
9 Fault elimination .................................................................47
9.1 Testing the tripping circuit and reason for tripping......................... 47
10 Disposal...............................................................................48
11 Technical data.....................................................................49
12 Appendix .............................................................................53
12.1 Dimensions with standard protective cover ................................... 53
12.2 Dimensions with OD protective cover............................................ 56

1 Introduction
5BA5789879-01 EN
This technical document contains detailed descriptions on the safe and
proper installation, connection, commissioning and monitoring of the prod-
uct.
It also includes safety instructions and general information about the prod-
uct.
This technical document is intended solely for specially trained and autho-
rized personnel.
1.1 Manufacturer
The product is manufactured by:
Messko GmbH
Gewerbegebiet An den Drei Hasen
Messko-Platz 1
61440 Oberursel
Germany
Phone: [phone]
Fax: [phone]
E-mail: [email protected]
Internet: www.reinhausen.com/messko
Further information on the product and copies of this technical document are
available from this address if required.
1.2 Subject to change without notice
The information contained in this technical file comprises the technical speci-
fications approved at the time of printing. Significant modifications will be in-
cluded in a new edition of the technical file.
The document number and version number of this technical file are shown in
the footer.
1.3 Completeness
This technical document is incomplete without the supporting documents.

1 Introduction
6 BA5789879-01 EN
The following documents apply to this product:
▪ Operating instructions
▪ Test certificate
1.4 Safekeeping
Keep this technical file and all supporting documents ready at hand and ac-
cessible for future use at all times.
1.5 Notation conventions
This section contains an overview of the symbols and textual emphasis
used.
1.5.1 Hazard communication system
Warnings in this technical file are displayed as follows.
1.5.1.1 Warning relating to section
Warnings relating to sections refer to entire chapters or sections, sub-sec-
tions or several paragraphs within this technical file. Warnings relating to
sections use the following format:
WARNING
Type and source of danger
Consequences
► Action
► Action
1.5.1.2 Embedded warning information
Embedded warnings refer to a particular part within a section. These warn-
ings apply to smaller units of information than the warnings relating to sec-
tions. Embedded warnings use the following format:
DANGER! Instruction for avoiding a dangerous situation.

1 Introduction
7BA5789879-01 EN
1.5.1.3 Signal words and pictograms
The following signal words are used:
Signal word Definition
DANGER Indicates a hazardous situation which, if not avoided, will result in
death or serious injury.
WARNING Indicates a hazardous situation which, if not avoided, could result
in death or serious injury.
CAUTION Indicates a hazardous situation which, if not avoided, could result
in minor or moderate injury.
NOTICE Indicates measures to be taken to prevent damage to property.
Table1: Signal words in warning notices
Pictograms warn of dangers:
Pictogram Definition
Warning of a danger point
Warning of dangerous electrical voltage
Warning of combustible substances

1 Introduction
8 BA5789879-01 EN
Pictogram Definition
Warning of a tipping hazard
Warning of a hot surface
Table2: Pictograms used in warning notices
1.5.2 Information system
Information is designed to simplify and improve understanding of particular
procedures. In this technical file it is laid out as follows:
Important information.
1.5.3 Instruction system
This technical file contains single-step and multi-step instructions.
Single-step instructions
Instructions which consist of only a single process step are structured as fol-
lows:
Aim of action
üRequirements (optional).
► Step 1 of 1.
ðResult of step (optional).
ðResult of action (optional).
Multi-step instructions
Instructions which consist of several process steps are structured as follows:

1 Introduction
9BA5789879-01 EN
Aim of action
üRequirements (optional).
1. Step 1.
ðResult of step (optional).
2. Step 2.
ðResult of step (optional).
ðResult of action (optional).
1.5.4 Typographic conventions
The following typographic conventions are used in this technical file:
Typographic convention Purpose Example
UPPERCASE Operating controls,
switches
ON/OFF
[Brackets] PC keyboard [Ctrl] + [Alt]
Bold Software operating con-
trols
Press Continue button
…>…>… Menu paths Parameter > Control pa-
rameter
Italics System messages, error
messages, signals
Function monitoring alarm
triggered
[► Number of pages]. Cross reference [► 41].
Table3: Typographic conventions

2 Safety
10 BA5789879-01 EN
This technical document contains detailed descriptions on the safe and
proper installation, connection, commissioning and monitoring of the prod-
uct.
▪ Read this technical document through carefully to familiarize yourself with
the product.
▪ This technical document is a part of the product.
▪ Read and observe the safety instructions provided in this chapter in partic-
ular.
▪ Observe the warnings in this technical document in order to avoid func-
tion-related dangers.
▪ The product is manufactured on the basis of state-of-the-art technology.
Nevertheless, risks to life and limb of the user or impairment of the prod-
uct and other material assets may occur during use due to function-re-
lated dangers.
2.1 Intended use
The pressure relief device protects transformers and on-load tap-changers
against impermissible pressure increases. At a predefined pressure, the
pressure relief device opens, relieves the pressure and closes tightly again
once the pressure has been relieved.
The product is designed solely for use in electrical energy systems and facili-
ties. If used as intended and in compliance with the requirements and condi-
tions specified in this technical document and the warning notices in this
technical document and attached to the product, the product does not
present any danger to persons, property or the environment. This applies
throughout the entire service life of the product, from delivery, installation
and operation to removal and disposal.
Intended use refers to the following:
▪ Only use the product with the transformer type specified in the order and
the associated operating data.
▪ You will find the standard valid for the product and the year of issue on the
nameplate.
▪ Operate the product in accordance with this technical document, the
agreed-upon delivery conditions and the technical data.
▪ Ensure that any necessary work is only performed by qualified personnel.

2 Safety
11BA5789879-01 EN
▪ Use the equipment and special tools supplied solely for the intended pur-
pose and in accordance with the specifications of this technical document.
▪ Only operate the product in industrial areas. Observe the notices in this
technical document regarding electromagnetic compatibility and the tech-
nical data.
2.2 Fundamental safety instructions
To prevent accidents, disruptions and damage as well as unacceptable ad-
verse effects on the environment, those responsible for transport, installa-
tion, operation, maintenance and disposal of the product or parts of the prod-
uct must ensure the following:
Personal protective equipment
Loosely worn or unsuitable clothing increases the danger of becoming
trapped or caught up in rotating parts and the danger of getting caught on
protruding parts. This results in danger to life and limb.
▪ All necessary devices and personal protective equipment required for the
specific task, such as a hard hat, safety footwear, etc. must be worn. Ob-
serve the "Personal protective equipment" [►Section 2.4, Page 14] sec-
tion.
▪ Never wear damaged personal protective equipment.
▪ Never wear rings, necklaces or other jewelry.
▪ If you have long hair, wear a hairnet.
Work area
Untidy and poorly lit work areas can lead to accidents.
▪ Keep the work area clean and tidy.
▪ Make sure that the work area is well lit.
▪ Observe the applicable laws for accident prevention in the relevant coun-
try.
Explosion protection
Highly flammable or explosive gases, vapors and dusts can cause serious
explosions and fire.
▪ Do not install or operate the product in areas where a risk of explosion is
present.

2 Safety
12 BA5789879-01 EN
Safety markings
Warning signs and safety information plates are safety markings on the
product. They are an important aspect of the safety concept. Safety mark-
ings are depicted and described in the chapter "Product description".
▪ Observe all safety markings on the product.
▪ Make sure all safety markings on the product remain intact and legible.
▪ Replace safety markings that are damaged or missing.
Ambient conditions
To ensure reliable and safe operation, the product must only be operated
under the ambient conditions specified in the technical data.
▪ Observe the specified operating conditions and requirements for the in-
stallation location.
Modifications and conversions
Unauthorized or inappropriate changes to the product may lead to personal
injury, material damage and operational faults.
▪ Only modify the product after consultation with Messko GmbH.
Spare parts
Spare parts not approved by Messko GmbH may cause physical injury and
damage the product.
▪ Only use spare parts approved by the manufacturer.
▪ Contact Messko GmbH.
Working during operation
You must only operate the product when it is in a sound operational condi-
tion. Otherwise it poses a danger to life and limb.
▪ Regularly check the operational reliability of safety equipment.
▪ Perform the inspection tasks described in this technical document regu-
larly.
2.3 Personnel qualification
The person responsible for assembly, commissioning, operation and inspec-
tion must ensure that personnel are sufficiently qualified.

2 Safety
13BA5789879-01 EN
Electrically skilled person
The electrically skilled person has a technical qualification and therefore has
the required knowledge and experience, and is also conversant with the ap-
plicable standards and regulations. The electrically skilled person is also pro-
ficient in the following:
▪ Can identify potential dangers independently and is able to avoid them.
▪ Is able to perform work on electrical systems.
▪ Is specially trained for the working environment in which (s)he works.
▪ Must satisfy the requirements of the applicable statutory regulations for
accident prevention.
Electrically trained persons
An electrically trained person receives instruction and guidance from an
electrically skilled person in relation to the tasks undertaken and the poten-
tial dangers in the event of inappropriate handling as well as the protective
devices and safety measures. The electrically trained person works exclu-
sively under the guidance and supervision of an electrically skilled person.
Operator
The operator uses and operates the product in line with this technical docu-
ment. The operating company provides the operator with instruction and
training on the specific tasks and the associated potential dangers arising
from improper handling.
Technical Service
We strongly recommend having repairs and retrofitting carried out by our
Technical Service department. This ensures that all work is performed cor-
rectly. If repair work is not carried out by our Technical Service department,
please ensure that the personnel who carry out the repairs are trained and
authorized to do so by Maschinenfabrik Reinhausen GmbH.
Maschinenfabrik Reinhausen GmbH
Technical Service
P.O. Box 12 03 60
93025 Regensburg
Germany
Phone: [phone]
Fax: [phone]

2 Safety
14 BA5789879-01 EN
E-mail: [email protected]
Internet: www.reinhausen.com
2.4 Personal protective equipment
Personal protective equipment must be worn during work to minimize risks to
health.
▪ Always wear the personal protective equipment required for the job at
hand.
▪ Never wear damaged personal protective equipment.
▪ Observe information about personal protective equipment provided in the
work area.
Personal protective equipment to be worn at all times
Protective clothing
Close-fitting work clothing with a low tearing
strength, with tight sleeves and with no protrud-
ing parts. It mainly serves to protect the wearer
against being caught by moving machine parts.
Safety shoes
To protect against falling heavy objects and slip-
ping on slippery surfaces.
Special personal protective equipment for particular environments
Safety glasses
To protect the eyes from flying parts and splash-
ing liquids.
Visor
To protect the face from flying parts and splash-
ing liquids or other dangerous substances.

2 Safety
15BA5789879-01 EN
Hard hat
To protect from falling and flying parts and mate-
rials.
Hearing protection
To protect from hearing damage.
Protective gloves
To protect from mechanical, thermal, and electri-
cal hazards.

3 Product description
16 BA5789879-01 EN
This chapter contains an overview of the design and function of the product.
3.1 Scope of delivery
The following components are included in the delivery:
▪ MPREC® pressure relief device
▪ Technical documents
▪ O-ring 95x3 (only for MPREC® with OD protective cover)
▪ Mounting seal ring (optional)
▪ Connecting flange for oil escape opening with internal thread or for weld-
ing (optional, and only for MPREC® with OD protective cover)
▪ Socket connection cable (optional and only for MPREC® with plug con-
nection)
Please note the following:
▪ Check the shipment for completeness using the shipping documents.
▪ Leave parts in the packaging and store in a dry area until installation.
3.2 Pressure relief device function description
The pressure relief device with the device flange is mounted tight on the
transformer tank or on the on-load tap-changer. If the internal pressure of
the transformer or on-load tap-changer exceeds the predefined tripping pres-
sure of the pressure relief device, the spring-loaded valve plate lifts off of its
seal seat within a few milliseconds. As a result, the internal pressure is re-
lieved as quickly as possible and the valve plate again closes the pressure
relief device tightly.
As an external indication that the valve has tripped, a self-locking signal pin
slides out of the housing and, as an option, a semaphore straightens.
Once the pressure falls below the tripping pressure, the valve closes again.
The signal pin and the semaphore must be reset in their operating positions
manually. The signaling contacts installed as an option are automatically re-
set.
The pressure relief device is available in 2 versions:
▪ With sheet-aluminum standard protective cover
▪ With cast-aluminum OD protective cover (Oil Directed = with directed oil
flow)
The construction and function are identical.

3 Product description
17BA5789879-01 EN
The pressure relief device is available with various tripping pressures.
Type Tripping pressure
[psi] [bar] [kPa]
LMPRD 4 psi 4 ± 1 0.28 +/- 0.07 28 +/- 6.9
LMPRD 6 psi 6 ± 1 0.41 +/- 0.07 41 +/- 6.9
LMPRD 8 psi 8 ± 1 0.55 +/- 0.07 55 +/- 6.9
LMPRD 10 psi 10 ± 1 0.69 +/- 0.07 69 +/- 6.9
LMPRD 12 psi 12 ± 1 0.83 +/- 0.07 83 +/- 6.9
LMPRD 15 psi 15 ± 2 1.03 +/- 0.14 103 +/- 13.8
LMPRD 20 psi 20 ± 2 1.38 +/- 0.14 138 +/- 13.8
LMPRD 25 psi 25 ± 2 1.72 +/- 0.14 172 +/- 13.8
LMPRD 30 psi 30 ± 2 2.07 +/- 0.14 207 +/- 13.8
Table4: Pressure range
3.3 Design/versions
The pressure relief device consists of a device flange with valve, spring as-
sembly, signal pin and protective cover; as an option also with 1 or 2 micro-
switches and with semaphore.
The design and the designation of the key device components are to be
found in the following drawings:
▪ Pressure relief device with standard protective cover [►Section 3.3.1,
Page 18]
▪ Pressure relief device with OD protective cover [►Section 3.3.2, Page
19] (Oil Directed = with directed oil flow)
The device flange of the pressure relief device is mounted with a mounting
seal tight on the counter flange of the transformer tank or the on-load tap-
changer cover. A spring assembly presses the valve plate against the seal
seat, which consists of one axially aligned and one radially aligned sealing
lip. The spring assembly is tensioned between a counter bearing and the de-
vice flange with 6 fixing screws.

3 Product description
18 BA5789879-01 EN
The signal pin has a cap that can be screwed off so that the protective cover
can be removed from the device flange. The signal pin has different colors
depending on the type and suitability of the gasket materials for various insu-
lation fluids in the transformer/on-load tap-changer:
▪ Red (anodized) for mineral oil
▪ Blue (anodized) for silicone oil, pyranol or similar
The optional micro-switches for the signaling contacts are encapsulated,
physically separate from the functioning part of the valve and therefore pro-
tected against environmental influences and leaking oil.
3.3.1 Pressure relief device with standard protective cover
The following graphic shows the key parts of the pressure relief device:
Figure1: Pressure relief device with standard protective cover
1 Device flange 2 3 housing screws M6x10, wrench
size 10
3 Seal (axial) with sealing lip (radial) 4 Ground connection (only with plug
connection)
5 Spring assembly 6 Cable bushing M20x1.5 for cable
diameter 8…15 mm; alternatively
without, with terminal box, with
ANSI plug or with Westinghouse
plug

3 Product description
19BA5789879-01 EN
7 Cable bushing M20x1.5 on the mi-
cro-switch
8 Protective cover
9 Signal pin (red for mineral oil, blue
for silicon oil)
10 Signal pin cap
11 Semaphore (optional) 12 1 or 2 micro-switches, alternatively
without
13 Counter bearing for spring assem-
bly
14 6 fixing screws
15 Valve plate 16 Mounting seal ring Ø 200 x Ø
178.5 x 4.25 mm [Ø 7.87" x Ø7.03"
x 0.17"] (optional)
3.3.2 Pressure relief device with OD protective cover
The OD protective cover has an escape opening for draining the oil in the
event of tripping. The escape opening is designed as a flange for closing a
pipe in order to enable the directed drainage of the escaping oil. An accom-
panying o-ring provides a tight seal for the flange connection.

3 Product description
20 BA5789879-01 EN
The following graphic shows the key parts of the pressure relief device:
Figure2: Pressure relief device with OD protective cover
1 Oil escape opening 2 Pipe connection with o-ring 95x3
and 3 hexagon screws M12x40
with washer and spring washer,
wrench size 19
3 OD protective cover 4 4 housing screws M8x100, wrench
size 13, max. torque 12 Nm
5 Signal pin with signal pin cap 6 1 or 2 micro-switches (optional)
7 Cable bushing M20x1.5 for cable
diameter 8…15 mm; alternatively
without, with terminal box, with
ANSI plug or with Westinghouse
plug
8 Ground connection (only with ver-
sion with plug)
9 Mounting seal ring Ø 200 x Ø
178.5 x 4.25 mm [Ø 7.87" x Ø7.03"
x 0.17"] (optional)
10 O-ring seal between device and
protective cover