General Information; Unpacking; Equipment Description; Transfer Switch Mechanism - Generac Power Systems RTS automatic Technical Manual

General Information

1.1

INTRODUCTION

This manual has been prepared especially for the purpose of famil-
iarizing personnel with the design, application, installation, opera-
tion and servicing of the applicable equipment. Read the manual
carefully and comply with all instructions. This will help to prevent
accidents or damage to equipment that might otherwise be caused
by carelessness, incorrect application, or improper procedures.
Every effort has been expended to make sure that the contents
of this manual are both accurate and current. The manufacturer,
however, reserves the right to change, alter or otherwise improve
the product at any time without prior notice.
1.2

UNPACKING

Carefully unpack the transfer switch. Inspect closely for any dam-
age that might have occurred during shipment. The purchaser must
file with the carrier any claims for loss or damage incurred while in
transit.
Check that all packing material is completely removed from the
switch prior to installation.
1.3

EQUIPMENT DESCRIPTION

The automatic transfer switch is used for transferring electrical
load from a UTILITY (NORMAL) power source to an GENERATOR
(STANDBY) power source. Such a transfer of electrical loads
occurs automatically when the UTILITY power source has failed or
is substantially reduced and the GENERATOR source voltage and
frequency have reached an acceptable level. The transfer switch
prevents electrical feedback between two different power sources
(such as the UTILITY and GENERATOR sources) and, for that rea-
son, codes require it in all standby electric system installations.
The transfer switch consists of a transfer mechanism, UTILITY
SERVICE DISCONNECT circuit breaker, a relay control, fuses, ter-
minal strip, and fuse holder for connection of sensing wires.
This transfer switch is suitable for use as service equipment.

1.3.1 TRANSFER SWITCH MECHANISM

These switches (Figure 1.1) are used with a single-phase system,
when the single-phase NEUTRAL line is to be connected to a
Neutral Lug and is not to be switched.
Solderless, screw-type terminal lugs are standard.
Switch Wire
Rating Range
100A #14-1/0 AWG
200A #6-250 MCM
This transfer switch is suitable for control of motors, electric dis-
charge lamps, tungsten filament and electric heating equipment
where the sum of motor full load ampere ratings and the ampere
ratings of other loads do not exceed the ampere rating of the
switch and the tungsten load does not exceed 30 percent of the
switch rating.
This UL listed transfer switch is for use in optional standby sys-
tems only (NEC article 702).
2
Conductor Tightening
Torque
50 in-lbs.
275 in-lbs.
This transfer switch is suitable for use on a circuit capable of
22,000 rms (200A) and 10,000 (100A) symmetrical amperes,
240 VAC maximum.
Figure 1.1 — Typical ATS Transfer Mechanism
UTILITY
CLOSING
COIL
GENERATOR
CLOSING
COIL

1.3.2 UTILITY SERVICE DISCONNECT CIRCUIT BREAKER

The utility service and generator disconnect circuit breakers for the
100 amp models are:
• Type BQ, 2-pole
• 120/240VAC, 100A
• 50/60 Hertz
• Heating, Air Conditioning and Refrigeration (HACR) rated
• Wire range: #1 - #8 AWG.
• The conductor tightening torque is 50 in-lbs.
The utility service circuit breaker for the 150/200 amp models
are:
• Type 225AF, 2-pole
• 120/240VAC, 150A/200A
• 50/60 Hertz
• Wire range: 300 MCM - 6 STR (Line), 250 MCM - 6 STR
(Load - ATS)
• The conductor tightening torque is 375 in-lbs. (Line), 275 in-
lbs. (Load - ATS)

1.3.3 LOAD SHED MODULE (LSM)

The Load Shed module 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 LSM; 2 air condi-
tioner loads and 4 other loads. The LSM 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 LSM.
• 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.
UTILITY LUGS
GENERATOR
LUGS (E1 & E2)
LOAD LUGS (T1 & T2)