G3PC

3

Operation

■ Failure Detection Function

Conditions for SSR Failure Detection

Note: 1. The contents of each of the above failure modes is as follows:

SSR short-circuit: SSR output circuit remains in the ON state.

SSR half-wave short-circuit: SSR output circuit remains in the ON state in one direction.

SSR open-circuit: SSR output circuit remains in the OFF state.

SSR half-wave open-circuit: SSR output circuit remains in the OFF state in one direction.

In addition to the failure modes listed above, detection of circuit disconnections for the load circuit is also possible. (As a rough guide,

circuit disconnection will be detected if the load impedance is greater than or equal to 1 M

Ω.)

2. The same power supply is used for both the detection and for the output circuit and so detection is not performed during power

interruptions.

3. If power supply (terminal 3) is in the open state, the SSR will still turn ON and OFF in the same way but the failure detection function and

alarm display will not operate properly.

Connection Diagrams (Main Circuit)

The following diagrams show the applicable load connection configurations for SSR failure detection.

Note: 1. With 3-phase connection, so that the power supply voltage is applied between the G3PC’s terminals 1/L1 and 3, connect the desired

phase to terminal 3.

2. When grounding to a neutral point with a three-phase start connection, an overvoltage will be applied to the G3PC if the neutral point

becomes disconnected, possibly causing product failure. Make sure the connection to the neutral point is secure.

3. Detection is not possible for the heater indicated with an asterisks with a three-phase delta connection.

Timing Chart

Note: After failure detection, if the detection conditions differ to the conditions given under Conditions for SSR Failure Detection, alarm output is

reset.

Failure mode

(See note 1.)

Operating input (between

terminals A1 and A2)

Detection time

Alarm display

(See note 3.)

Alarm display (between

terminals X1 and X2)

(See note 3.)

SSR short-circuit

OFF

0.5 s max. (See note 2.)

Red

Open collector transistor

output

SSR half-wave short-circuit OFF

SSR open-circuit

ON

SSR half-wave open-circuit ON

Single Phase

3-phase Star

Connection

3-phase Delta

Connection (3-phase,

2-wire Switching)

3-phase V

Connection

G3PC

G3PC

G3PC

G3PC

G3PC

G3PC

G3PC

G3PC

Heater

Main circuit power

supply (load side)

Operating input

(between terminals

A1 and A2)

Input LED

(yellow)

Load current

RDY/ALM LED

(Green:

; Red:

)

Alarm output

(between terminals

X1 and X2)

SSR ON normally

SSR OFF normally

SSR short-circuit

Reset (See note.)

SSR open-circuit

Reset (See note.)

SSR failure detection

Circuit disconnection detection on the load side

Load circuit disconnection

Reset (See note.)