MTL SD32R surge protection device MTLSD32R

MTL SD32R surge protection device MTLSD32R

Guide to applications and selection
The SD range of SPDs includes models for almost all possible applications operating at voltages up to 250V AC. The optional ‘fuse/disconnect’ package provides both fused protection against fault currents and a convenient method of isolating field circuitry from protected circuitry without needing additional disconnect terminals. The standard fuse (which is replaceable) is rated
250mA with 50mA fuses also being available by special request.
Where only the disconnect feature is required, solid links can be used.As an example, this feature is of particular value in applications
in which an SPD is used with a bulk power supply feeding 

MTL SD32R surge protection device MTLSD32R

multiple loops. The individual module fuse prevents a fault or follow on current on one loop disrupting the power supply to the others. Also, loops can be removed from the circuit for maintenance reasons or added without needing additional disconnect terminals.
The following guide to selection suggests the most suitable SDs for a number of specific applications. For technical information, see the detailed specifications on the back page of this publication (some field circuit protection is shown for completeness)

MTL SD32R surge protection device MTLSD32R

Analogue inputs (high-level)
2-wire transmitters, 4-20mA, conventional
and smart
The SPDs recommended for use with
‘conventional’ and ‘smart’ 4-20mA
transmitters (fed by a well-regulated supply)
are the SD32 and SD55, the choice depending
upon the maximum working voltage of the
system (32V and 55V respectively). The
diagram illustrates a prime example of an
application for which the fuse/disconnect
facility is particularly useful, however, both
models are available in ‘X’ versions without
the optional fuse/disconnect feature.

MTL SD32R surge protection device MTLSD32R

MTL SD32R surge protection device MTLSD32R

SD16R SD32X SD32R SD07R

SD32R SD55R SD07R SD32R

SD07 SD16 SD32 SD55 SD16X

SD55X SD32T3 SD07R3 SD16R3

SD32R3 SD55R3 SDRTD SDPSTN

SD150X SD275X

Jackie Ma