Simpson 260 Series - Simpson 260 Series Description

Introduction
1.1.3 Improved Overload Protection: In addition to improved
overload protection, the relay circuit reduces the nuisance and
cost of fuse replacement due to minor overloads.
1.2
DESCRIPTION
1.2.1 Overload Protection:
a. All the ranges, with exception of 10 AMPS, 500/1000 VAC
and DC are protected by an electronic overload protection
system. The protection is from the usual overloads that would
damage the VOM. A transistorized circuit senses the voltage
drop across the indicating instrument and actuates a relay when
the voltage reaches approximately 3 to 4 times rated full scale
voltage. Sensing of the voltage drop is by means of a bridge
network so that overload protection is provided regardless of
polarity. The relay operates at a uniform percent of overload
since the indicating instrument circuit is common to all ranges.
When actuated by an overload, the relay contacts, which are
in the -COMMON CIRCUIT, latch open until the reset button
on the front panel is depressed. The reset button is located to
the right of the +1V jack.
WARNING
e Due to its sensitivity to overloads, the electronic over-
load protection relay incorporated in the 260-7P is sus-
ceptible to electrostatic fields from high potentials or
transients either in the circuit being measured or in
nearby circuitry.
e Do not assume the relay to be faulty if it trips out with-
out apparent cause. It may be indicating a dangerous
condition such as excessive circuit-to-ground (floating)
voltage being applied to the Instrument.
e Avoid touching the Instrument or its test leads until