Surge Protection - Introduction to the Problem
The nuts and bolts of the world’s best Lightning
More than 700,000 installations worldwide.
Understanding the Problem
Electric charges generated in a thunderstorm
discharge to the ground with a current of approximately
20kA to 150kA.
Lightning induced surges occur in a cable as a result
of rapid and violent changes in the magnetic field
intensity generated around the cable.
The surge propagates in the cable, and instantaneously
applies high energy to the electronics equipment connected
to both ends of the cable.
Interline breakdowns occur when electronic components
are directly hit and destroyed by lightning surges
generated between two cable conductors connected to
In discharge breakdowns, a lightning
surge creates a very high potential difference between
two conductors and ground.
As a result, a discharge occurs between some parts
of the circuit and areas electrically grounded, such
as the metal housing. Electronic components are damaged
by some of the discharge current that flows through
The effects of induced surges on connected equipment
are more severe when the connecting cable is longer;
the induced current is higher; or the equipment is
located closer to the site of the lightning strike.
Every year lightning destroys many
millions of dollars of sensitive
electronic equipment. Millions more are lost through
down time and the loss of production or mission-critical
That’s why companies around
the world depend on in-line M-RESTER
Surge Protectors to protect both signal and power
Surge Protectors absorb only the
lightning surges with no
interruption of the instrumentation signal.
M-System offers superior protection
across a side range of applications.
DC or pulse signal lines
Absorb lightning surges transmitted in 4-20 mADC and
pulse signal wiring to ensure the line potential will
remain at a low voltage.
Receiving instruments from thermocouples
Absorb lightning surges entering the temperature transmitter
or a controller through the thermocouple and/or thermocouple
M-RESTER Surge Protectors absorb
only the lightning
surges with no interruption of the instrumentation
RTD and RTD wire receiving instruments
Protect RTD transmitters from damage caused by surges
on the RTD wiring.
Potentiometer and receiving instruments
Protect potentiometer transmitters from lightning
surges that enter the wiring between the potentiometer
and the transmitter in applications such as water
level sensors and valve position indicators.
Pulse generating or receiving devices
Protect frequency generating devices such as flowmeters
and frequency transmitters from lightning surges that
enter the wiring between these instruments.
ON-OFF signal lines – eight channel
Protect semiconductor switches used for ON-OFF outputs
from the computer or PLC from lightning surges entering
through the wiring.
Load cells (strain gauges) and wires, receiving
Protect load cell transmitters from lightning surge
damage that enters the wiring between the load cell
and the transmitters.
Protect telecommunications equipment from lightning
surges entering through the telecommunication line
Twisted-pair cable lines for MsysNet, RS-422/485
Absorb lightning surges entering through twisted-pair
cables linking each MsysNet device or similar peripheral
Power supply lines – small and medium
Wide range of units protect electronic equipment such
as computers and telemetering systems from lightning
surges that enter through substations and step-down
transformers. Also effective in rejecting switching
transients generated by thyristors, circuit breakers
and motor starters.
Large instrumentation panels,
computer systems or telemetering systems
Designed to protect large instrumentation panels,
computer systems and telemetering systems in central
control rooms or operations centers. ncorporates air-core
reactors, large-capacity discharge elements and electromagnetic
contactors. Thermal fuse, in parallel with the discharge
elements, opens the operating circuit for the electromagnetic
contactor, offering fail-safe protection in severe