3
1.3.3 LOAD SHED MODULE (LSM)
The Overload Prevention Control Board is designed to prevent an
overload on the generator when it is supplying the customer loads.
See Figure 1.2. Up to six loads can be managed by the OPCB; 2 air
conditioner loads and 4 other loads. The OPCB manages the loads
by “shedding” the connected loads in the event of a drop in generator
frequency (overload). Loads to be “shed” are grouped in 4 priority
levels on the OPCB.
• Priority 1 and 2 has connections for both one air conditioner and
one contactor. Both an air conditioner and a contactor can be
used at the same time if desired. To control an air conditioner,
no additional equipment is required. Internal relays interrupt the
thermostat 24VAC control signal to disable the air conditioner load.
• Priority 3 and 4 have connections for one contactor only.
• Four LEDs, located on the Overload Prevention Control Board,
will indicate when a load priority level is enabled. When loads are
connected, the LEDs will be illuminated.
• Any loads, including central air conditioners, can be controlled
via a contactor that must be purchased separately. Up to four
contactors can be controlled by the Overload Prevention Control
Board. (The 24 VAC or 120 VAC is supplied through the OPCB to
energize each contactor coil).
• Generator overload condition is determined by generator frequen-
cy. Loads are shed when the frequency is <58Hz for 3 seconds or
<50Hz for ½ Second (for 60Hz).
The OPCB has a Test button which forces the unit to act as if an
overload has occurred. This button operates even when the transfer
signal is inactive.
Figure 1.2 — Overload Prevention Control Board
0 Ground
194 +12V
23 Transfer
T1
NEUTRAL
A/C 1
24V
A/C 2
24V
LOAD 1
LOAD 2
LOAD 3
LOAD
4
A/C 1 & LOAD 1
LOAD
SUPPLY
LOAD
SUPPLY
1
2
1
2
2
2
2
1
1
1
1A MAX
1A MAX
1A MAX
1A MAX
A/C 2 & LOAD 2
LOAD 3
LOAD 4
Air Conditioner Connections:
Up to two A/Cs can be
controlled here via their low
voltage thermostat wires
Status LEDs: Shows which
loads are currently allowed to
run
Load Connections: Up to four
loads of any type can be
controlled via these
connections. A separate
contactor module is required
2
2
1
2
1
2
1
2
2
1
1
1.4 TRANSFER SWITCH DATA DECAL
A DATA DECAL is permanently affixed to the transfer switch enclo-
sure. Use this transfer switch only with the specific limits shown on
the DATA DECAL and on other decals and labels that may be affixed
to the switch. This will prevent damage to equipment and property.
When requesting information or ordering parts for this equipment, make
sure to include all information from the DATA DECAL.
Record the Model and Serial numbers in the space provided for future
reference.
MODEL #
SERIAL #
1.5 TRANSFER SWITCH ENCLOSURE
The standard switch enclosure is a National Electrical Manufacturer’s
Association (NEMA) and UL 3R type. UL and NEMA 3R type enclo-
sures primarily provide a degree of protection against falling rain and
sleet; undamaged by the formation of ice on the enclosure.
1.6 SAFE USE OF TRANSFER SWITCH
Before installing, operating or servicing this equipment, read the
SAFETY RULES (inside front cover) carefully. Comply strictly with all
SAFETY RULES to prevent accidents and/or damage to the equip-
ment. The manufacturer recommends that a copy of the SAFETY
RULES are posted near the transfer switch. Also, be sure to read all
instructions and information found on tags, labels and decals affixed
to the equipment.
Two publications that outline the safe use of transfer switches are
the following:
• NFPA 70; National Electrical Code
• NFPA 70E; Standard for Electrical Safety in the Workplace
• UL 1008, STANDARD FOR SAFETY-AUTOMATIC TRANSFER
SWITCHES
NOTE:
It is essential to use the latest version of any standard to ensure
correct and current information.
General Information
