Securitron BPSM_Series - Manual (Page 3)

PN# 500-19400
Page 3 Rev. E, 02/11
power supply has gone into automatic shut off (discussed later). Always replace any blown
fuse with the same rated fuse.
The DC fuse should only trip if there is a short circuit in the supply itself (downstream short
circuits or overloads will trip individual Polyswitches). This could occur if the F1-H terminal block
somehow contacts DC negative. Alternately, if you are not using the “P” terminals for
downstream wiring but are using the “H” terminal to operate an individual, high current,
downstream load, a short circuit or overload could trip the DC fuse.
Securitron’s power supply family contains an additional safety feature which is automatic shut
off in the event of a DC short circuit or overload. This is often called a “crowbar” circuit. When
you are using the power supply without batteries, a DC short circuit will usually cause the
power supply to shut itself off rather than tripping any fuse or Polyswitch. If batteries are
implemented, however, they will attempt to drive into the load as soon as the short circuit or
overload occurs and the fuses and/or Polyswitches will trip to maintain safety.
If this happens there is a reset procedure. First, correct the overload condition. Next,
remove all current from the Polyswitch for a period of 10 seconds. You do this by
moving the associated slide switch to the “off” position. Then wait 10 seconds, return the slide
switch to “on” and operation will return to normal. If you haven’t corrected the overload,
naturally the Polyswitch will trip again but you must always de-power and re-power the
Polyswitch to reset it.
The multiple safety features of these power supplies can be confusing so the following chart
provides summary information on operation of the safety features when the power supply is
used with and without batteries.
* A Polyswitch can individually trip in an overload condition without batteries in the special case
where the overload current is greater than the Polyswitch trip current (2.5 Amps) but less than
the power supply output capacity. This is unusual. A pure short circuit is more common and
this will put the supply into Auto shut-off.
AC FUSE DC FUSE POLYSWITCH AUTO SHUTOFF
WITHOUT
BATTERIES
Will trip only if
internal
transformer
shorts (all LED’s
will be out)
Generally will not
trip. Supply will
go into auto shut-
off in case of
overload (all LED’s
will be out)
Generally will not
trip. Supply will
go into auto shut-
off in case of
overload* (all
LED’s will be out).
Will generally
occur in the case
of any short or
overload (all LED’s
will be out)
WITH
BATTERIES
Will trip only if
internal
transformer
shorts (all LED’s
will be out)
Will trip if terminal
F1, F2 or H shorts
to negative or in
case of overload
when terminal H is
used as single
output (all LED’s
will be out)
Will trip in the
event of individual
zone short or
overload
(individual zone
LED will be out or
dim)
Batteries drive into
short or overload
which trips
another safety
feature unless
overload current is
less than fuse or
Polyswitch rating.
LED DIAGNOSTIC TABLE
RED (DC) on GREEN (AC) on
FRONT PANEL CONTROL BOARD DESCRIPTION
ON ON Normal Operation
ON OFF Battery backup is powering output
OFF ON No DC output
OFF OFF No AC, no battery or discharged battery