Hitachi 152SO, Installation & Operation Manual, Page: 18 / 36

PN-152SO Switch Overload Relay
Copyright 2019 SM 5929 Rev. 23, March 2019 4-4
Set resistor R-2 to provide 0.013 ampere to pick-up stick relay. Momentarily close
switch “S” to position “1” to pick-up the Heavy Duty relay, which will be held energized
over its own front contact.
Then throw switch “S” to the position “2” to energize overload relay. By adjusting R-1,
set the “overload” current at the value specified in Table 4-2. At this current value the
operating relay should pick-up within 10% of the time value specified in Table 4-2. A
small adjustment of the operating time can be obtained by reducing or increasing the
distance between the turns of the thermal resistor.
Figure 4-3. Final Calibration
When the operating relay picks up, it energizes the stick relay, which in turn releases
the heavy-duty relay. When the heavy-duty relay drops out, it interrupts the overload
current circuit to the operate relay. (Heavy duty release interrupts the overload current
to the operate relay, which drops out.)
Successive tests of operating time must be made. Allow sufficient time for the thermal
resistor to return to room temperature between tests.
REAR VIEW OF PN-152SO RELAY MOUNTING BASE
11C
11A
HV+
DC+
12C
HV-
12B
W DC-
A
R-1
R-2
A
"OPERATE"
D.C. AMMETER
S
1
2
"STICK"
D.C.
AMMETER
10 T0 12 V.D.C.
+
_
1F
1H
2F
2H
12V
COIL
HEAVY
DUTY
RELAY
10 OR 12V
RELAY WITH 2
FROT CONTACTS
CAPABLE OF
INTERRUPTING
20 AMP AT
12VDC
NOTE: R-1 RESISTOR MUST BE
CAPABLE OF CARRYING
20 AMPS INTERMITTENTLY.
R-2 RESISTOR IS TO ADJUST
CURRENT TO 0.013 AMPS.
12A
4C
5.
00
44
.0
0