Eaton TP48-3-I-NDI Surge Protection MTL Crouse Hinds

MTL TP48 range
Safeguards electronic process
transmitters against induced
surges and transients from
field cabling
The TP48 range of surge protection devices uniquely provide a level
of protection for 2, 3 and 4 wire field-mounted transmitters that is far
in excess of the optional transient protection facilities available from
the transmitter manufacturers – without involving any additional wiring,
conduit modifications or other expensive extras.
The TP48 range protection network consists of high-power, solidstate electronics and a gas-filled discharge tube capable of diverting
20kA impulses. The whole unit is encased in a 316 stainless steel
housing, threaded for the common conduit entries used on process
transmitters. Versions are available for 1/2” NPT, 20mm ISO, and
G1/2” (BSP 1/2 inch) threaded entries.
Installation can easily be carried out retrospectively to existing
installations. The TP48 is screwed into any unused conduit entry on the
transmitter case and flying leads are connected to the terminal block
(+ve, -ve) and the internal earth stud. The 3 wire TP protects +ve, -ve
and signal. The 4 wire TP48 protects +ve, -ve, signal +ve and -ve. The
TPs operate without in any way affecting normal operation – passing ac
or dc signals without attenuation while diverting surge currents safely
to earth and clamping output voltages to specific levels.
The all-important earthing connection is made to the local casing
of the transmitter with no separate earth connection or ground stake
at the transmitter being needed. In operation, the TP48 makes sure
that the transmitter electronics are never exposed to damaging
transients between lines or between lines and casing/earth. Any surge
current appearing as a series-mode or common-mode transient is
converted into a common-mode voltage – whereupon the transmitter
electronics are temporarily raised to some higher voltage level before
‘floating’ down automatically (and without damage) to resume normal
operation.
For hazardous area use, approvals for both intrinsically safe and
flameproof (explosion-proof) operation are available (pending for
the TP48 3 & 4 wire), in all gas groups and apparatus temperature
classification up to T4 for the TP48 3 & 4 wire and T6 for the TP48.
Where transmitters are used in circuits suitable for Div 2/Zone 2
installations, the TP can be added without adversely affecting the level
of safety.
For fieldbus applications, use the TP32 which meets the
requirements of IEC61158-2:2004 and ANSI/ISA-50.02-2 1992 for
31.25kbit/s systems as used by Foundation™ fieldbus, PROFIBUS-PA
and WorldFIP.
• Protects 2, 3 and 4 wire transmitters
• Easy and direct mounting — screws into
spare conduit entry
• Intrinsically safe and flameproof to
CENELEC standards
• Parallel connection avoids introduction of
any resistance into loop
• ATEX approved