K2CM

12

Testing Method

■ Current Reverse-phase Detection Models

The operating characteristics listed in the table below are

tested using the circuit shown on the right. Decide the number

of conductor passes through the holes of the current trans-

former in accordance with the operating current range of the

Motor Protective Relay and by referring to the current setting

method described under Operation, Setting, and Indication.

* Balance the currents between phases by adjusting variable resistor R1.

** If a current equal to 600% of the set current value cannot be attained by adjusting the voltage regulator, increase the number of conductor passes

through the holes of the current transformer.

Test item

Test procedure

Operating value

Operating time

Over-

current

Inverse type

1. Turn ON SW1.

2. Turn ON SW2 to operate auxiliary relay Y.

3. Gradually increase the current by adjusting the voltage

regulator. With inverse-type models, read the value of the

current when the overcurrent LED indicator blinks. With

instantaneous-type models, read the value when it lights

(continuously).*

4. Turn OFF SW1 and SW2.

1. Turn ON SW1 and SW2. Increase the current to 600% of

the set current value by adjusting the voltage regulator.

Turn OFF SW1 and SW2.**

2. Turn ON SW1.

3. Turn ON SW2 and read the position (i.e., time) of the

pointer of cycle counter CC when CC is stopped by the

operation of the K2CM. The read time is the operating time

for inverse-type models and the lock time of the instanta-

neous-type models.

4. Turn OFF SW1 and SW2.

Instantaneous

type

1. Turn ON SW1 and SW2. Increase the current to 100% of

the set current value by adjusting the voltage regulator.

Turn OFF SW1 and SW2.

2. Turn ON SW1 and SW2 again and wait 2 seconds mini-

mum.

3. Using the voltage regulator, abruptly increase the current

to 140% of the set current value. Confirm that the K2CM

performs instantaneous operation.

4. Turn OFF SW1 and SW2.

Open-phase

1. Open (disconnect) any one of the input phases for the cur-

rent transformer.

2. Turn ON SW1 and SW2. Gradually increase the current by

adjusting the voltage regulator.

3. Confirm that the K2CM operates at a current no greater

than 85% of the set current value and that, at this current,

the trip indicator is orange and the open-phase LED indica-

tor lights.

4. Turn OFF SW1 and SW2.

1. Open (disconnect) any one of the input phases for the cur-

rent transformer.

2. Turn ON SW1 and SW2. Increase the currents of the other

two phases to 115% of the set current value by adjusting

the voltage regulator. Turn OFF SW1 and SW2 temporarily.

3. Turn ON SW1 and SW2 again. Read the position (i.e.,

time) of the pointer of cycle counter CC when CC is

stopped by the operation of the K2CM.

4. Turn OFF SW1 and SW2.

Reverse-phase

1. Interchange any two phases at a position closer to the

power supply than the current transformer. (In the above

figure, phases U and V are interchanged as shown by the

dotted lines.)

2. Turn ON SW1 and SW2. Decrease the current to 50% of

the set current value by adjusting the voltage regulator.

Then turn OFF SW1 and SW2 temporarily.

3. Turn ON SW1 and SW2 again. Confirm that the K2CM

operates, the trip indicator is orange, and that the reverse-

phase LED lights.

4. Turn OFF SW1 and SW2.

1. Interchange any two phases at a position closer to the

power supply than the current transformer. (In the above

figure, phases U and V are exchanged as shown by the

dotted lines.)

2. Turn ON SW1 and SW2. Increase the current to 100% of

the set current value by adjusting the voltage regulator.

Then turn OFF SW1 and SW2 temporarily.

3. Turn ON SW1 and SW2 again. Read the position (i.e.,

time) of the pointer of cycle counter CC when CC is

stopped by the operation of the K2CM.

4. Turn OFF SW1 and SW2.

Y

UV

W

CC

100 V

C

K2CM Motor Protective Relay

3

φSD: Three-phase voltage regulator (5 to 15 A)

A:

AC ammeter (5 A)

V:

AC voltmeter (300 V)

CC:

Cycle counter

Y:

Auxiliary relay (15 A)

R1:

Variable resistor (50

Ω, 400 W + 400 W)

Fixed resistor (50

Ω, 400 W + 400 W)

200 V

50/60 Hz

(3-phase)

100 VAC

50/60Hz

3

φSD

±

Minimum set time is 2 s.