Honeywell CTP-20 - Manual (Page 2)

SOLID CORE AND SPLIT CORE 4-20 MA OUTPUT CURRENT SENSORS
62-0245—01 2
WARNING
The secondary of the 5A Current Transformer
(C.T.) must be shorted together before the
power may be turned on from the device.
For applications in which the normal operating current is
greater than 200 or 250 Amps, depending on the model,
or for conductor diameters larger than 0.75 in. (19 mm) in
diameter, an external 5 Amp Current Transformer (C.T.)
must be used in conjunction with a CTS20-005 or CTS20-
005VFD as shown in Fig. 5.
Fig. 3. Current transformer
Latch Operation (Split Core Models)
Pressing down on the two (2) side tabs and swinging the
cover open, opens the split core current switch as shown
in Fig. 6. Lifting up the latch with a flat-tip screwdriver as
shown in Fig. 7 can also open the unit. Press down firmly
on the cover to close the current switch. An audible “click”
will be heard as the tab slides over the tongue on the
base.
CAUTION
Mating surfaces of the magnetic core are
exposed when the sensor is open. Silicone
grease, present on the cores to prevent rust,
can capture grit and dirt if care is not
exercised. Operation can be impaired if
anything prevents good contact between pole
pieces. Visually check the mating parts of the
core before closing the current sensor.
Fig. 4. Opening sensor by hand
Fig. 5. Opening with a screwdriver
Wiring
Honeywell recommends the use of 16 to 22 AWG (1.3 to
0.3 mm
2 ) shielded cable, copper wire only for all current
sensor applications. A maximum wire length of less than
98.4 feet (30 meters) should be used between the current
sensors and the Building Management System or
controller.
NOTE: When using a shielded cable, be sure to connect
only (1) end of the shield to ground at the
controller. Connecting both ends of the shield to
ground may cause a ground loop.
When removing the shield from the sensor end, make
sure to properly trim the shield so as to prevent any
chance of shorting. The current sensor terminals are
polarity sensitive and represent a linear and proportional
4 to 20 mA output signal. The current sensors are
available in either an Average or True RMS output
version. The recommended torque to be used on the
terminal block connections is 5.93 in-lbs (0.67 Nm). The
EXAMPLE: FOR CURRENTS UP TO 600 AMPS, USE A 600:5 RATIO C.T.
AS SHOWN.
INSULATED CONDUCTOR
600:5 RATIO 5A C.T.
WIRE NUT
M25295A
C
U R L US
C
U S
R U L
M25298
M25299
C
US
R U L