K2CM

8

Nomenclature

10 (side) 9

6

7

8

R S T

R S T

1 pass

2 passes

Current-setting Knob

• By operating the setting knob, set the current value to

be equal to the rated current of the motor to be used.

The current-setting knob uses the same scale as the

rated current. Therefore, the operating value will be

115% of the set current value.

Example:

Operating current value

= 12

× 1.15 (115%) = 13.8 A

• The List of Current Settings shows an example. The

rated current differs depending on the motor’s type,

construction, manufacturer, etc. Therefore, set the

operating current after checking the specifications of

the motor.

Trip Indicator

In normal operation, only the upper half of the display window is colored orange,

whereas when the motor circuit has tripped, the entire display window becomes orange.

Time-setting knob*

Reset Button

• With manual resetting models, when the motor circuit trips during

normal operation or test operation, the operation indicators and

the output relay can be immediately reset by pressing the reset

button.

• When the motor circuit trips due to reverse-phase with automatic

resetting models, the operation indicators and the output relay can

be immediately reset by pressing the reset button.

• Reset button operation is ineffective when the operation power

supply is OFF. When the motor circuit trips during normal opera-

tion, identify the abnormal input function by checking the LED indi-

cators, then turn OFF the power switch of the main circuit and

proceed with troubleshooting. After the abnormality is removed,

turn ON the power switch of the main circuit to reset the K2CM.

Test Button

Inverse Type

• Operation checks of the overcurrent function can be performed.

• Pressing the test button for the time-setting value will cause the motor

circuit to trip.

• With manual resetting models, even if the test button is released after

the motor circuit has tripped, the circuit remains tripped, whereas with

automatic resetting models, the motor circuit continues operating and

the output relay releases.

• Be sure to perform the test operation with the overcurrent switch set to

ON. Set both the open-phase and reverse-phase switches to OFF. If

one of these switches is set to ON, the motor circuit may trip if an

open-phase or reverse-phase occurs before an overcurrent does.

Instantaneous Type

• Perform the test operation with input current at 0 and the overcurrent

switch set to ON.

• Pressing the test button for the set start-up lock time will cause the

motor circuit to trip.

• With manual resetting models, even if the test button is released after

the motor circuit has tripped, the circuit remains tripped, whereas with

automatic resetting models, the motor circuit continues operating and

the output relay releases.

Deciding the Number of Primary Conductor Passes

• When using a motor with a small current rating, decide the num-

ber of primary conductor passes through the current transformer

holes and the tap setting by referring to the List of Current Set-

tings.

• Pass all the three wires through the respective holes of the current

transformer. Basically, the wires should be passed through the

specified holes. If this is difficult, however, they can be passed

through any holes provided that the phase order is R, S, and T.

• If the wires are passed through the holes only once, a current within

the full scale of the current-setting knob can be set. If they are

passed more than once, however, the current setting range will

change according to the number of passes. The current setting

range when the number of conductor passes is n can be obtained

by dividing the full scale of the current-setting knob by n. For exam-

ple, the current setting range of the K2CM-

@@L@ is 8 to 26 A when

the wires are passed only once. This range is 4 to 13 A when the

wires are passed twice, 2 to 6.5 A when the wires are passed four

times, and 1 to 3.25 A when the wires are passed eight times.

The wires can be passed through the holes any number of times. It

is convenient for the calculation, however, if the number of passes

is 2, 4, or 8.

• The signal from a high-voltage motor is input to the Motor Protec-

tive Relay via an external current transformer. In this case, the cur-

rent can be set in the same manner as above by dividing the rated

current of the high-voltage motor by the transformation ratio of the

current transformer.

Time-setting Knob

• Set the required operating time by operating the time-setting knob.

(With instantaneous-type models, the set operating time is used as the

start-up lock time).

Note: 1. The setting scale is the op-

erating time when 600% of

the current value is input.

2. The required operating

time varies depending on

the type of motor, load con-

dition, etc. You can take the

time from when the motor

starts to when the motor

enters the steady state as

a guide for setting this val-

ue. When setting the oper-

ating time for submersible

motors, which require very

short operating times, con-

sult the manufacturer to

obtain the correct operat-

ing time. An operating time

shorter than 5 s can be

used as a rough guide.

• The scale multiplying factor

can be selected by the time

scale multiplying factor

switch.

Scale

multiplying

factor

Time scale

multiplying factor

switch

Time scale

value

× 1 (s)

× 4 (s)

22

8

33

12

44

16

55

20

66

24

77

28

88

32

99

36

10

10

40