Omron H3CR-A Manual page 300

H3BH
!
Caution
Inputs to H3BA, H3BA-FA and H3BH-8R
A transformer is not used in the power supplies for the H3B Se-
ries. You can therefore receive an electrical shock by touching
the input terminals when the power supply voltage is being ap-
plied. Take adequate precautions to protect against electrical
shock.
When connecting the contact of transistor for external input sig-
nal to the input terminals of the Timer, pay attention to the follow-
ing points to prevent short-circuiting due to sneak current to the
transformerless power supply.
Do not connect two or more Timers to an external input signal
contact simultaneously.
H3BH-8R
For the power supply of an input device, use an isolation trans-
former, of which the primary and secondary windings are mutu-
ally isolated and the secondary winding is not grounded.
ALL DIMENSIONS SHOWN ARE IN MILLIMETERS.
To convert millimeters into inches, multiply by 0.03937. To convert grams into ounces, multiply by 0.03527.
Cat. No. L31-E1-6
300
Power Supply Connection
If the Timer is connected to an AC power supply, its two-pole ter-
minals can be connected to the power supply in either direction,
regardless of the polarity. But if it is connected to a DC power
supply, be sure to connect the Timer's power terminals to the
correct polarities.
Use sine wave for the waveform of an AC power supply. Use a
DC power supply having a ripple factor of 20% or less and sup-
plying a mean voltage that is within the rated operating voltage
range of the Timer.
Make sure that the supply voltage is applied to the Timer all at
once, using contacts such as of a switch or relay. If the supply
voltage is applied gradually, the Timer may not be able to per-
form power reset or its set time may be up when it should not.
Power Source Connection
Because the AC-operated version is a capacitive load, the solid-
state relay to be used must be rated at a dielectric strength two
times that of the Timer to switch the power source of the Timer.
Wiring
H3BH Timer has a high impedance circuit and thus may be in-
fluenced by inductive voltage. Consequently, the Timer may not
release. To prevent this, keep the wiring of the Timer cables as
short as possible. Also, do not route the cables in parallel with
power lines. If the inductive voltage runs to 30% of the rated sup-
ply voltage or higher, connect an RC filter (with C = 0.1 &F and R
= 120 $) or a bleeder resistor across the power terminals of the
Timer. Connecting a bleeder resistor also suppress residual
voltage cause by leakage current.
H3BH