9
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Connection to contact output type controller:
When connected to ON/OFF signal, output is produced upon shorting the C1-C2 terminals.
8-2. Connection of More Than One Unit to Controller
In case the controller is of the current input type, control input signals should be wired in series.
When the allowable range of load resistance of the 4-20mA output controller is 600Ω, maximum of six units can be connected.
Since PAC27 units have control circuits of different electric potentials, auto and manual have to be switched individually.
9. Alarm Function (standard equipment)
9-1. Overcurrent Protection Alarm
This alarm is put into action when the value of current detected by the regulator (built-in CT) exceeds approx. 130% of the rated current, blocks
gate signals of thyristors and stops output, at which time current flows across the alarm output terminals AL1 and AL2. The monitor lamp [O.C.]
lights. When the overcurrent protection alarm is activated, turn the power off and apply it again to reset the alarm.
Power should be turned on again after removing the cause of overcurrent.
9-2. Thyristor Overheating Alarm
This alarm is put into action when thyristor elements are heated to exceed its rated temperature, blocks the gate signal of the thyristor and stops
output, at which time current flows across the alarm output terminals AL1 and AL2. The monitor lamp [O.H.] lights.
The normal state is restored automatically when the thyristor temperature falls due to absence of output.
When this function is in action, use the instrument in improved radiating conditions or with reduced load current.
9-3. Thyristor Trouble Alarm
The trouble modes of thyristor element are mostly short-circuits.
This function is in action when there is output voltage without control-input signal or when it is extremely slight if any, and current flows across
the alarm output terminals AL1 and AL2. The monitor lamp [THY] lights.
When the load is open, a high voltage is generated on the output side and this alarm is activated. Do not energize the instrument while the load
is open. If the thyristor trouble lamp lights despite a load being connected, repair will be required.
Please call our local business office or service center nearest you.
The AL1 and AL2 are common output terminals for the 4 alarms.
1. Monitor lamp [O.C.] lights: The action of the overcurrent protection circuit - Standard
2. Monitor lamp [O.H.] lights: The action of the SCR overheating alarm - Standard
3. Monitor lamp [THY] lights: The action of the SCR trouble alarm - Standard
4. Monitor lamp [FUSE] lights: Rapid fuse break - Optional
In the case of PAC27P2 -
