Omron K8AK-PH1 200/500VAC Manual page 6

Single-phase overcurrent/undercurrent relay

Table of Contents

K8AK-AW

Example Relay Sequence for Overcurrent/Undercurrent Monitoring Mode

• RY2 (magnet contactor) will be energized in approx. 100 ms when PB1 (startup button) is pressed.

• Use a timer for the K8AK undercurrent alarm (AL2) as a switch from contact "b" to contact "a" will not occur for approx. 250 ms even if the magnet

contactor (RY2) is turned on.

• TA

: Timer (H3YN-2 + socket, Omron)

• Operating mode : Interval mode

• Setting time

: 2 s

Before pressing the startup button (after approx. 1.25 seconds have passed following turning on the power supply of K8AK)

Magnet contactor for load switching OFF

Immediately after pressing the startup button (within approx. 250 ms)

Magnet contactor for load switching ON

Two seconds after pressing the startup button

Magnet contactor for load switching ON

Note: 1. K8AK output contacts will operate (contact "a") within the setting range for current input values (normal status).

2. The overcurrent alarm (AL1) and undercurrent alarm (AL2) will operate as follows before the magnet contactor (RY2) is turned on (state

without current input).

• Overcurrent alarm (AL1): Contact "b" for the approx. 1 second interval immediately after the K8AK control power supply is turned on. After that, a switch

• Undercurrent alarm (AL2): Contact "b" for the approx. 1 second interval immediately after the K8AK control power supply is turned on. After that, because

Load

RY2

K8AK

Load

RY2

K8AK

Load

RY2

K8AK

to contact "a" will be made as an overcurrent state is no longer present. At that time, there will be a response delay time from

contact "b" to contact "a" of approx. 250 ms.

a state without current input will continue, an undercurrent will be detected and the status of contact "b" will continue as is.