Instruction Manual

Watlow Series PD ■ 12 ■ Chapter 2 Install and Wire
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Warning:
Use National Electric (NEC) or
other country-specific standard
wiring and safety practices when
wiring and connecting this con-
troller to a power source and to
electrical sensors or peripheral
devices. Failure to do so may re-
sult in damage to equipment and
property, and/or injury or loss of
life.
Note: Current transformer (CT)
must be purchased separately.
Note: A process output cannot be
installed on Output 1 or 3 when
using current transformer input.
Figure 12a — Current Transformer Input 2, Single Phase
• Input impedance 100Ω, Vac only
The current transformer must be purchased separately. Watlow current
transformer part number is 16-0246 (up to 50 amps).
Systems that are more than 50 amps need an interstage transformer. For
example, if you use a 300 amp current transformer, part number 16-0073,
and an interstage transformer, part number 16-0176, the 300 amp current
transformer provides a 5 amp signal to the interstage transformer. In turn,
the interstage transformer provides a 20 mA maximum signal to the con-
troller.
Figure 12b — Current Transformer Input 2, Three Phase
1 2 3 4
Bk
Red
Red
WhBk
BkWh
Bk
16-0176
Transformer
CT
CT
L1
L3
L2
5A
20mA
3-phase current sensing up to 300 amp
To CT Input 2
To CT Common
1
3
CT Common
CT Input 2
L3
L1
L2
Phase
dot
1 2 3 4
1
3
CT Common
CT Input 2
L2
L1
CT
Load wire
Center leg not used
AC Load
CT Input 2
CT Common
0 to 5A
AC
0 to
20mA
A
Single phase current sensing up to 300 amp
16-0176
Transformer