User`s manual

WATLOW DIN-A-MITE Style C User's Manual
17
NOTE: The current transformers must be in the controlled legs on a 2-leg DIN-A-MITE. The
load wires must pass through the current transformers in the same direction.
Non-latching Alarm Option
(models DC_ _ - _ _ S _ - H _ _ _ )
Open Heater and Shorted SCR Alarm
The shorted SCR detector compares the input
command signal and actual load current. If
load current is present without an input signal
then the shorted SCR alarm will energize a
triac (on board the DIN-A-MITE) output.
An open-heater or partial open-heater state is
detected when a command signal is present
and a reduced or no output current is detected.
The alarm output is then energized.
This is a non-latching alarm. This output can
be used to drive various indication devices,
such as a coil, light, buzzer, etc. See the
alternative latching circuit section below.
VÅ
13
14
Triac
RY1
Coil
Reset Switch
RY1A
L1
L2
RY1B
Normally open
Common
Normally closed
(External alarm relay
contacts, set A)
(External alarm relay
contacts, set B)
Latching Alarm Relay Circuit
Ungrounded Delta or Wye Load 3-phase, 2-leg DIN-A-MITE
CR1
Current
Transformers
Delta
Load
Ungrounded
Wye Load
6
5
4
V~
(ac)
120 or 240 V~ (ac)
@ 300 mA maximum
energizes on alarm
Semiconductor
Fuses
Signal
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1 2 3
4 5 6
Signal Alarm
Gain
Bias
Open
Heater
Limit
+
-
+
-
+
-
ALM
ALM
CT1
CT1
CT2
CT2
CT3
CT3
Adjustment
Potentiometers
Alarm Relay
or Indicator
1A
DIN-A-MITE
DC20-48S0-H000
2-Leg
Zone
1
Zone
2
Zone
3
black
white