Current Transformer - ero electronic ELK Guía Del Usario

2.11. Current Transformer

The current transformer input is an optional input in
all model sizes.
It can be connected to monitor the rms current in an
electrical load and to provide load diagnostics. The
following fault conditions can be detected: SSR (solid
state relay) short circuit, heater or SSR open circuit
and partial load failure. These faults are displayed as
alarm messages on the controller front panel.
ELK model
CT Input
13
14
Note: C is common to both the CT input and Digital
input A. They are, therefore, not isolated from each
other.
20
ETK model
CT Input
7
8
•
CT input current: 0-50mA rms (sine wave,
calibrated) 50/60Hz
•
A burden resistor, value 10Ω, is fitted inside the
controller.
•
It is recommended that the current
transformer is fitted with a voltage
limiting device to prevent high
voltage transients if the controller is
unplugged. For example, two back
to back zener diodes. The zener voltage should be
between 3 and 10V, rated at 50mA.
•
CT input resolution: 0.1A for scale up to 10A, 1A
for scale 11 to 100A
•
CT input accuracy: +4% of reading.
Part number HA028438. Issue 3.0. Oct-05