22 Solid-state Multi-functional Timer H3CR-A
Safety Precautions (H3CR-A)
Note: The undermentioned is common for all H3CR-A models.
■ Power Supplies
For the power supply of an input device of the H3CR-A@/-A@S/-AP,
use an isolating transformer with the primary and secondary wind-
ings mutually isolated and the secondary winding not grounded.
The H3CR-A@/-A@S/AP’s power supply terminal 2 is a common ter-
minal for input signals to the Timer. Do not disconnect the wires on
terminal 2, otherwise the internal circuitry of the Timer will be dam-
aged.
Make sure that the voltage is applied within the specified range, oth-
erwise the internal elements of the Timer may be damaged.
■ Input/Output
Relationship between Input and Power
Supply Circuits (except for H3CR-A8E)
The H3CR-A (except for H3CR-A8E) uses transformerless power
supply. When connecting a relay or transistor as an external signal
input device, pay attention to the following points to prevent short-cir-
cuiting due to a sneak current to the transformerless power supply. If
a relay or transistor is connected to two or more Timers, the input ter-
minals of those Timers must be wired properly so that they will not
differ in phase, otherwise the terminals will be short-circuited to one
another.
It is impossible to provide two independent power switches as shown
below regardless of whether or not the Timers are different in phase.
S,G, R
5, 6, 7
2
10
2
H3CR-A
Power supply
Isolation transformer is required.
Input device
Input
terminal
Correct
H3CR-A
Power
supply
Input
terminal
Input device
10
2
2
Incorrect
Isolation
transformer
S,G, R
5, 6, 7
5, 6, 7
G, S, R
10
2
H3CR-A
Input terminal
Power supply
H3CR-A
Power supply
Incorrect
Correct
Short-circuit current
Contact or transistor for
external input signal
Input
terminal
Input
terminal
Input
terminal
Input
terminal
Power supply
Input
terminal
Input
terminal