K2CM

9

LED Indicators

When the motor circuit trips due to overcurrent, open-phase, or

reverse-phase, the respective LED indicator lights (continuously).

The overcurrent indicator also indicates the start of operation.

• With the inverse-type models, when the motor current exceeds the

overcurrent operating value, the overcurrent indicator blinks at the

bright level and then remains lit at the dimmed level. After the oper-

ating time has elapsed, with the manual resetting models, the

motor circuit trips and the overcurrent indicator remains lit at the

bright level, whereas with automatic resetting models, the indicator

remains lit at the bright level until the motor current descends below

the resetting value.

• Since the indicator status is not stored in memory when the opera-

tion power supply is turned OFF, be sure to check which indicators

were illuminated when the motor circuit was tripped.

The functions of the K2CM can be used in the following seven combi-

nations. For each function, turn ON the corresponding setting switch.

When the setting switches for overcurrent, open-phase, or reverse-

phase function are turned OFF, the following functions becomes

invalid.

1. Overcurrent Setting Switches

These switches select the overcurrent setting and the multiplying fac-

tor linked with operating time setting.

2. Open-phase Setting Switches

These switches select the open-phase detecting function and the

“High” or “Low” current imbalance factor for operation.

3. Reverse-phase Setting Switches

These switches select the reverse-phase detection function and

reverse-phase polarity. By selecting the reverse-phase polarity

accordingly, the K2CM can operate normally without changing the

connections when wired with the order of the phases reversed.

If the K2CM detects reverse-phase although the motor is rotating in

the forward direction (e.g., because of incorrect wiring of power

lines), set the reverse-phase polarity switch to the “Reverse” position

to enable normal operation.

Note: The K2CM detects reverse-phase at a point before the current

transformer. If a reverse connection is made at the load side far

from the current transformer and the motor rotates in the re-

verse direction, the K2CM does not detect the reverse-phase.

Reverse-detectable Range

* The reverse-phase polarity switching function is applicable to cur-

rent reverse-phase detection models only.

Function

Overcurrent

Open-phase

Reverse-phase

Combination

1ON

2ON

3ON

4ON

ON

5ON

ON

6ON

ON

7

ONONON

Function setting switch

set to OFF

Invalid function

Overcurrent

Time setting and multiplication

Open-phase

“High” and “Low” imbalance factors

Reverse-phase

“Forward” and “Reverse” function

Overcurrent

detecting function

ON

Enabled

OFF

Disabled

Time setting

multiplying factor

× 4 (s) Time setting scale value × 4 = 8 to 40 s

× 1 (s) Time setting scale value × 1 = 2 to 10 s

Open-phase

detecting

function

ON

Enabled

OFF

Disabled

Imbalance factor

High

The motor circuit operates at an

operating imbalance factor of 35

±10%.

Low

The motor circuit operates at an

operating imbalance factor of 60%.

Start

Trip

Bright

Bright

Dimmed

Overcurrent operating value

(115% of current-setting value)

Motor current

Reverse-phase

detecting

function

ON

Enabled

OFF

Disabled

Reverse-phase

polarity

Normal

The motor circuit trips at reverse-

phase when a reverse-phase is

detected.

Reverse

Used when a reverse-phase

connection is made in the power line

of the motor at a point before the

current transformer (including

external current transformer).

Phase condition

Normal

Reverse

Reverse

Connections

Reverse-phase

polarity switch

position

Normal

Normal

Normal

Trip

None

Yes

None

Direction of

motor rotation

Forward

Reverse

(See below.)

Reverse

Coun-

ter-

mea-

sure

Reverse-

phase

polarity

switch

position

Reverse Reverse Reverse Reverse

Wiring

Wiring

changed

at (A).

Wiring

changed

at (B).

Wiring

changed

at (C).

Wiring

changed

at (D).

Direction of

motor rotation

Forward

RS

M

T

Motor

relay

RS

T

RS

M

T

Motor

relay

RS

T

(A)

(B)

RS

M

T

Motor

relay

RS

T

(C)

(D)

RS

M

T

RS

T

Detectable:

Reverse-phase state can be detected with the

motor protective relay only on the power supply

side.

Undetectable: Reverse-phase state on the motor side cannot

be detected with the motor protective relay.