YOKOGAWA CW120 - Chapter 5. Wiring; Precautions for Wiring the Circuit under Test

5-1
IM CW120-E
Wiring
5
Chapter 5. Wiring
5.1 Precautions for Wiring the Circuit
under Test
WARNING
• When wiring the CW120 or CW121, or when it is turned off, turn off the circuit under test. It is
highly dangerous to connect or disconnect voltage or clamp-on current probes without first
turning off the circuit under test.
• Be extremely careful not to connect any voltage-mode circuit to the current input terminals or
any current-mode circuit to the voltage input terminals. Miswiring can result in not only dam-
age to the circuit under test or equipment under test but also injury to personnel.
• Do not apply any input level higher than the following to the voltage or current input terminals
(the upper limit differs depending on the probe used):
Maximum allowable input (continuous)
Voltage input: 495 Vrms
Current input – for 96033 probe: 130 Arms
for 96030 probe: 250 Arms
for 96031 probe: 625 Arms
for 96032 probe: 700 Arms (1000 Arms for 5 minutes)
Input ratings for each range
Voltage input: 150/300/450 V
Current input – for 96033 probe: 5/10/20/50 A
for 96030 probe: 20/50/100/200 A
for 96031 probe: 50/100/200/500 A
for 96032 probe: 200/500/1000 A
SEE ALSO
For details, see Chapter 14, “Specifications.”
WARNING
• If using an external voltage transformer (VT) or current transformer (CT), make sure the trans-
former can adequately withstand the voltage being measured. Be extremely careful not to
allow the secondary stage of the CT to become open-circuited while the CT is being electrified.
Otherwise, a high-voltage may develop on the secondary stage, causing extreme danger.
• The maximum allowable input voltage range of the external control input terminals is -0.5 to
5.5 V. Do not apply voltages exceeding this range, otherwise the input circuitry may be dam-
aged. (When wiring the input terminals, ensure that you wire the right terminals.)
• Do not use any probe other than the voltage probes supplied with the CW120/121 or dedicated
clamp-on current probes.
• Do not use a clamp-on probe with any non-insulated conductors.