FAQ
Q. How is a loop repaired after activation?
A. Plastic optical fibre does not require special tools and can be joined using our fast and economical field repair kits. In fact even scissors and sticky tape could be used, certainly not recommended however illustrates how robust and tolerant the loop continuity check function is. For short loops such as inside a circuit breaker it may be faster to simply replace with a new length. PyrOnodes can be either replaced or reset depending on access restrictions.
Q. How is the point of failure identified?
A. Generally a loop and relay would be provided for each sub circuit or equipment section, in the same way as electrical protection systems are designed. Should an activation occur knowing exactly where in the loop is of no practical value, to complete a repair the associated section will need to be isolated and accessed anyway, at which time the point of failure will be obvious.
Q. How is this an efficient solution if the loop needs repair after activation?
A. Connection failure is typically a low frequency event, anything other than this and there is probably an underlying design issue. The work required to splice or replace the fibre is inconsequential to the repair activity that will be needed should an activation occur. The reality is other online systems force you to make a connection at every point during installation even though most will never fail, now that's inefficient! Sensor connections themselves are a point of weakness, PyrOptic virtually eliminates this problem trading the limited practical value of individual connection discrimination for grouped connections.
Q. What makes PyrOptic so reliable?
A. PyrOptic is a new take on old technology, thermostat wax. This material can be found in everything from planes and automobiles to greenhouses and heating systems. Thermostat wax rapidly expands during phase change, the temperature this occurs at is controlled during a multi phase manufacturing process resulting in an inert material with virtually indefinite life span. PyrOnodes are small thermal hydraulic actuators which capture this expansion to cut the optical fibre. Other design features and level of functionality have been carefully considered to optimise the solution including the use of an unbroken optic loop and commercially available relays that can be sourced from multiple vendors . This simplicity is how PyrOptic can guarantee long term reliability.
Q. Thermal imaging can detect small temperature differences between phase connections, can PyrOptic be as effective?
A. PyrOptic is more effective because it's monitoring 24/7, thermal imaging is intermittent. This said, other online monitoring systems enable continuous differential temperature comparison to identify developing failures early on. Yes, they will catch these failures faster than PyrOptic however at typically 10 to 20 times the cost, with far greater system complexity and in most applications it simply doesn't matter. All these combined with the probability of failure and quantity of connections is why PyrOptic is the optimised solution for the vast majority of electrical assets.
Q. Why monitor temperature?
A. Electrical protection has never effectively manged connection degradation and thermal runaway. The world has recognised the hazards of joint failure in electrical systems for along time, for industry this is manifested in routine maintenance and inspections such as thermal imaging, for residential installations the electrical codes of Canada and the United Sates have mandating arc-fault circuit interrupter (AFCI) devices in recognition that faulty domestic installations were causing 40,000 residential fires each year resulting in 350 deaths and 1,400 injuries. Unfortunately the technology behind AFCIs won't detect glowing connections, also known as high resistance joints which can exceed temperatures of 1000°C. This has been a major criticism and for good reason, arcing faults are simply far less common than high resistance joints.
In business you need to manage risk and electrical assets are inherently so. AS/NZS 3000, section 1.5 Fundamental Principles specifies excessive temperatures as one of the three major electrical installation risks, this is common theme all over the globe. Thermal runaway has been historically managed using a combination of design, protection systems, routine maintenance and verification. PyrOptic is a solution that monitors temperature, the only direct way to detect failing electrical joints. Deploying PyrOptic throughout an electrical installation can enable the elimination of thermal imaging, visual inspection and micro ohm testing routines. This all directly results in improved safety and plant reliability at a lower cost.
Q. Why do electrical connections fail?
A. For many reasons, such as cyclical thermal expansion, unbalanced and overloaded conditions, duty cycles, mechanical wear and stress, poor workmanship, vibrations, harmonics and the inevitable mechanism of impurity film buildup.
It is not well understood that electrical connections have a design life, connection quality deteriorates with time due chemical reaction at the jointed surfaces (impurity film buildup). Operating temperatures, currents, surface materials and jointing methods are some of the factors in how fast the connection degradation occurs. As connections deteriorate their temperature increases, accelerating the chemical reaction and ultimately leading to thermal run away and catastrophic failure.
Q. How are PyrOnodes rated?
A. PyrOnodes are available with activation temperatures ranging from 60 to 105°C. Each PyrOnode temperature designation has detailed characterisation data, e.g. a PYR-82 has a maximum normal operating temperature limit of 76°C, above this the cutting mechanism begins to act on the optical fibre with a complete cut occurring at 82°C, furthermore the time to operate at 82°C is approximately 120 seconds and as the temperature increases above this the speed of operation becomes faster. Further information is available in the PyrOnode product section.
Q. What is the correct temperature limit to select?
A. It’s best to understand the maximum normal operating temperatures of the equipment and then use a PyrOnode with a maximum operating temperature above this. If this is not already known, non-reversible thermal indication stickers/labels can be an effective, low cost and safe way to determine this (Tempil, Brady and Omega, to name a few)
Q. I don't know what the maximum normal operating temperature of the equipment is and it’s difficult to obtain, I do know the system uses insulation with X°C rating, does that help?
A. Yes, choose a PyrOnode with a maximum operating temperature limit that's above the insulating rating. This method simply may not provide the earliest possible warning.
Q. What about selection for un-insulated bus bars?
A. Ideally the highest normal operating temperature should be obtained. Otherwise as a general guide the temperature where accelerated connection surface deterioration occurs can be used. For example it's generally accepted that bare copper to copper connections should not operate above 80°C to ensure long term reliability of connections. A PYR-92 would allow excursions to 86°C and catch thermal runaway before serious damage occurred.
Q. Can I select a temperature rating thats too high?
A. For preventing catastrophic failures due to thermal run away, not really. When connection deterioration starts to occur it's only going one way, and that's from hot to hotter. Even if a PYR-105 was installed on a V75 rated connection it would still provide useful alarming, its just that the chance of permanent damage to the insulation is increased. It all depends on the duration of temperature rise from insulation rating to chosen activation temperature and that could be anywhere from seconds to months or even longer!
Q. What signal comes out of the monitoring relay and how can it be used?
A. Fibre Optic amplifier relays typically have NPN and PNP open collector outputs. These can be used to drive digital inputs and interposing relays for plant alarms and even automatically tripping circuits.
Q. Can PyrOptic be used for other applications?
A. Absolutley! PyrOptic is suited to risky yet infrequent events with application ranges between 60 to 105°C. Additional functionality can be achieved such as accurately determining the position of a break using more advanced loop integrity check techniques (OTDR). Materials can also be changed to suit different environments e.g. stainless steel.
Contact us (sales@pyroptic.com) to discuss your application!
A. Plastic optical fibre does not require special tools and can be joined using our fast and economical field repair kits. In fact even scissors and sticky tape could be used, certainly not recommended however illustrates how robust and tolerant the loop continuity check function is. For short loops such as inside a circuit breaker it may be faster to simply replace with a new length. PyrOnodes can be either replaced or reset depending on access restrictions.
Q. How is the point of failure identified?
A. Generally a loop and relay would be provided for each sub circuit or equipment section, in the same way as electrical protection systems are designed. Should an activation occur knowing exactly where in the loop is of no practical value, to complete a repair the associated section will need to be isolated and accessed anyway, at which time the point of failure will be obvious.
Q. How is this an efficient solution if the loop needs repair after activation?
A. Connection failure is typically a low frequency event, anything other than this and there is probably an underlying design issue. The work required to splice or replace the fibre is inconsequential to the repair activity that will be needed should an activation occur. The reality is other online systems force you to make a connection at every point during installation even though most will never fail, now that's inefficient! Sensor connections themselves are a point of weakness, PyrOptic virtually eliminates this problem trading the limited practical value of individual connection discrimination for grouped connections.
Q. What makes PyrOptic so reliable?
A. PyrOptic is a new take on old technology, thermostat wax. This material can be found in everything from planes and automobiles to greenhouses and heating systems. Thermostat wax rapidly expands during phase change, the temperature this occurs at is controlled during a multi phase manufacturing process resulting in an inert material with virtually indefinite life span. PyrOnodes are small thermal hydraulic actuators which capture this expansion to cut the optical fibre. Other design features and level of functionality have been carefully considered to optimise the solution including the use of an unbroken optic loop and commercially available relays that can be sourced from multiple vendors . This simplicity is how PyrOptic can guarantee long term reliability.
Q. Thermal imaging can detect small temperature differences between phase connections, can PyrOptic be as effective?
A. PyrOptic is more effective because it's monitoring 24/7, thermal imaging is intermittent. This said, other online monitoring systems enable continuous differential temperature comparison to identify developing failures early on. Yes, they will catch these failures faster than PyrOptic however at typically 10 to 20 times the cost, with far greater system complexity and in most applications it simply doesn't matter. All these combined with the probability of failure and quantity of connections is why PyrOptic is the optimised solution for the vast majority of electrical assets.
Q. Why monitor temperature?
A. Electrical protection has never effectively manged connection degradation and thermal runaway. The world has recognised the hazards of joint failure in electrical systems for along time, for industry this is manifested in routine maintenance and inspections such as thermal imaging, for residential installations the electrical codes of Canada and the United Sates have mandating arc-fault circuit interrupter (AFCI) devices in recognition that faulty domestic installations were causing 40,000 residential fires each year resulting in 350 deaths and 1,400 injuries. Unfortunately the technology behind AFCIs won't detect glowing connections, also known as high resistance joints which can exceed temperatures of 1000°C. This has been a major criticism and for good reason, arcing faults are simply far less common than high resistance joints.
In business you need to manage risk and electrical assets are inherently so. AS/NZS 3000, section 1.5 Fundamental Principles specifies excessive temperatures as one of the three major electrical installation risks, this is common theme all over the globe. Thermal runaway has been historically managed using a combination of design, protection systems, routine maintenance and verification. PyrOptic is a solution that monitors temperature, the only direct way to detect failing electrical joints. Deploying PyrOptic throughout an electrical installation can enable the elimination of thermal imaging, visual inspection and micro ohm testing routines. This all directly results in improved safety and plant reliability at a lower cost.
Q. Why do electrical connections fail?
A. For many reasons, such as cyclical thermal expansion, unbalanced and overloaded conditions, duty cycles, mechanical wear and stress, poor workmanship, vibrations, harmonics and the inevitable mechanism of impurity film buildup.
It is not well understood that electrical connections have a design life, connection quality deteriorates with time due chemical reaction at the jointed surfaces (impurity film buildup). Operating temperatures, currents, surface materials and jointing methods are some of the factors in how fast the connection degradation occurs. As connections deteriorate their temperature increases, accelerating the chemical reaction and ultimately leading to thermal run away and catastrophic failure.
Q. How are PyrOnodes rated?
A. PyrOnodes are available with activation temperatures ranging from 60 to 105°C. Each PyrOnode temperature designation has detailed characterisation data, e.g. a PYR-82 has a maximum normal operating temperature limit of 76°C, above this the cutting mechanism begins to act on the optical fibre with a complete cut occurring at 82°C, furthermore the time to operate at 82°C is approximately 120 seconds and as the temperature increases above this the speed of operation becomes faster. Further information is available in the PyrOnode product section.
Q. What is the correct temperature limit to select?
A. It’s best to understand the maximum normal operating temperatures of the equipment and then use a PyrOnode with a maximum operating temperature above this. If this is not already known, non-reversible thermal indication stickers/labels can be an effective, low cost and safe way to determine this (Tempil, Brady and Omega, to name a few)
Q. I don't know what the maximum normal operating temperature of the equipment is and it’s difficult to obtain, I do know the system uses insulation with X°C rating, does that help?
A. Yes, choose a PyrOnode with a maximum operating temperature limit that's above the insulating rating. This method simply may not provide the earliest possible warning.
Q. What about selection for un-insulated bus bars?
A. Ideally the highest normal operating temperature should be obtained. Otherwise as a general guide the temperature where accelerated connection surface deterioration occurs can be used. For example it's generally accepted that bare copper to copper connections should not operate above 80°C to ensure long term reliability of connections. A PYR-92 would allow excursions to 86°C and catch thermal runaway before serious damage occurred.
Q. Can I select a temperature rating thats too high?
A. For preventing catastrophic failures due to thermal run away, not really. When connection deterioration starts to occur it's only going one way, and that's from hot to hotter. Even if a PYR-105 was installed on a V75 rated connection it would still provide useful alarming, its just that the chance of permanent damage to the insulation is increased. It all depends on the duration of temperature rise from insulation rating to chosen activation temperature and that could be anywhere from seconds to months or even longer!
Q. What signal comes out of the monitoring relay and how can it be used?
A. Fibre Optic amplifier relays typically have NPN and PNP open collector outputs. These can be used to drive digital inputs and interposing relays for plant alarms and even automatically tripping circuits.
Q. Can PyrOptic be used for other applications?
A. Absolutley! PyrOptic is suited to risky yet infrequent events with application ranges between 60 to 105°C. Additional functionality can be achieved such as accurately determining the position of a break using more advanced loop integrity check techniques (OTDR). Materials can also be changed to suit different environments e.g. stainless steel.
Contact us (sales@pyroptic.com) to discuss your application!
