MESSKO® MPREC®
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Reliable Protection Against Overpressure in Oil-Filled Transformers
Protect your transformer and tap changer from critical pressure peaks. The MESSKO® MPREC® enables rapid pressure relief and helps prevent severe damage and downtime.
How it works
When the defined pressure level is exceeded, the valve opens and reduces the pressure. At the same time, a signal is triggered to indicate the event. After pressure normalization, the valve closes securely again.
Why this product
- Reduces the risk of critical transformer damage
- Fast response time in emergency situations
- Improves overall system reliability
- Minimizes downtime and maintenance costs
- Suitable for indoor and outdoor applications
Features
- Mechanical signal pin for trip indication
- Up to 2 micro-switches (NO/NC)
- Protection class IP66
- Connection via terminal box, cable gland* or special connectors*
- Corrosion protection up to C5H* or CX*
*Optional features available. Contact us for more information.
Available MESSKO® MPREC® Variants
| Function | MPREC 8 PSI 685-SM08NS2BPZO |
MPREC 10 PSI 685-SM10NS2BPZO |
MPREC 20 PSI 685-SM20NS2BPZO |
|---|---|---|---|
| Type | Standard-cover | ||
| Bleed screw | ✓ | ||
| Pickup pressure | 8 psi (0.55 bar) | 10 psi (0.69 bar) | 20 psi (1.38 bar) |
| Gasket material | NBR for mineral insulating oil | ||
| Micro-switch design | Standard switch | ||
| Number of micro-switches | 2 | ||
| Electrical connection | Terminal box IP66 | ||
| Color | RAL 7033 – cement grey | ||
| Semaphore | ✗ | ||
| Protection class | IP66 | ||
| Ambient air temperature | -40 °C ... +80 °C | ||
Legend
✓ = available | ✗ = not included
Available pressure ranges for MESSKO® MPREC®
The defined response pressure describes the opening point of the pressure relief device and must be selected according to the transformer design.
| Type | LMPRD 08 | LMPRD 10 | LMPRD 20 |
|---|---|---|---|
| PSI | 8 psi (±1) | 10 psi (±1) | 20 psi (±2) |
| Bar | 0.55 bar | 0.69 bar | 1.38 bar |
| kPa | 55 kPa | 69 kPa | 138 kPa |
Documents
| Name | Category | Date | File size | Download |
|---|---|---|---|---|
MESSKO® MPREC® Pressure relief device |
Operating instruction | 10/2023 | 3.865 KB |
 |
|
MESSKO® MPREC® |
Flyer | 05/2025 | 457 KB |
|
FAQ - Frequently Asked Questions
How does the MESSKO® MPREC® pressure relief device work?
The device operates with a spring-loaded valve mechanism. When the internal pressure exceeds the defined response pressure, the valve plate lifts within a few milliseconds and releases the pressure. After the pressure drops, the valve closes automatically and restores the sealing function.
How is a tripping event indicated?
A tripping event is indicated mechanically by a self-locking signal pin that remains in the alarm position after activation. In addition, optional micro-switches provide electrical signals for remote indication and integration into tripping circuits.
What pressure ranges are available?
The MESSKO® MPREC® is available in defined pressure ranges from 4 psi up to 30 psi, depending on the variant. The response pressure determines the opening threshold of the device and must be selected according to transformer design requirements.
Can the device be integrated into protection systems?
Yes, the device can be equipped with up to two micro-switches with normally open and normally closed contacts. These allow integration into transformer protection systems and circuit breaker tripping circuits.
What connection options are available?
Electrical connections can be realized via cable glands, terminal box or plug connections depending on the device configuration. This allows flexible integration into existing systems.
Is the device suitable for outdoor and harsh environments?
Yes, the device is designed for indoor and outdoor applications. It supports protection class up to IP66 and can be supplied with corrosion protection classes according to ISO 12944, including options for offshore and demanding environments.
Does the device require maintenance?
The pressure relief device itself is maintenance-free. However, regular inspection as part of transformer maintenance is recommended, including visual checks and functional verification.
Can the device be retrofitted?
Yes, the MESSKO® MPREC® can be installed on existing transformers or on-load tap-changers, provided the mechanical interface and application conditions are compatible.
Problem with the installation? No problem at all!
Discover our how-to videos for many products.
Welcome to our how-to videos section, your ultimate guide to easy installation, commissioning and maintenance. Our videos provide you with clear and understandable instructions specifically designed to make it easier for you to use our products.
These videos complement our operating instructions and provide additional visual support for a seamless implementation of your projects. Take a look at our videos and make your life easier.
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Dissolved Gas Analysis (DGA)
Download the DGA Application Guide and protect your transformers from unexpected failures
Our free Application Guide provides information on how Dissolved Gas Analysis (DGA) can help detect transformer failures early.
Learn what problems are caused by gases in the transformer oil and how continuous monitoring of hydrogen, carbon monoxide and moisture using an online DGA sensor can help prevent costly transformer downtime.
With your newfound knowledge, you can improve your equipment monitoring and minimize the risk of downtime and costly repairs.
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