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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
EQUIPMENT DESCRIPTION
The LTS transfer switch will provide three major functions.
The first function is to provide an automatic transfer switch.
The automatic transfer switch is used for transferring electrical
loads from a UTILITY (NORMAL) power source to a GENERATOR
(STANDBY) power source. Such a transfer of electrical loads
occurs automatically when (connected to a Generac engine gen-
erator) the UTILITY power source has failed or is at a substantially
reduced voltage and the GENERATOR source voltage and frequen-
cy 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 reason, codes
require it in all standby electrical system installations.
The second function is to provide a means to divide up the electri-
cal loads on the electrical system. The electrical loads are to be
divided into "critical loads" and non-essential loads. The "critical"
loads are connected to the internal 16 circuit panel board. The
non-essential electrical loads are to be powered from the load shed
switch (LSS).
The UTILITY source will supply all electrical loads at all times.
When the transfer signal is given by the engine generator controller,
all loads, both critical and non-essential loads, are connected to
the GENERATOR supply. If the generator is overloaded the LSS will
operate and disconnect the non-essential loads which results in a
reduction in the load on the generator.
The third function is a 16 circuit load center to connect the "criti-
cal loads" to. These loads will be normally powered by the UTILITY
source and will be backed up by the GENERATOR source. The
Siemens load center is provided with the following Siemens type
QP circuit breakers; 1-50A 2-pole, 1-40A 2-pole, 1-20A 2-pole,
5-20A single pole and 5-15A 2-pole circuit breakers.
The LTS transfer switch is suitable for use as SERVICE ENTRANCE
EQUIPMENT – UTILITY (NORMAL) source only. The LTS is only
SERVICE ENTRANCE rated for the USA. The 200A 2-pole circuit
breaker provided is the "service disconnect" and is labeled as
such. An additional disconnect must be readily available for the
alternate source, unless the alternate source is an accessible gen-
erator and can be shutdown.
2
1.2.1 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
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.
Figure 1.1 — Typical ATS Transfer Mechanism
UTILITY
CLOSING
COIL
GENERATOR
CLOSING
COIL
This transfer switch is for use in optional standby systems only
®
(NEC
Article 702).
This transfer switch is suitable for use on a circuit capable of
22,000 rms symmetrical amperes, 240 VAC maximum.
1.2.2 UTILITY SERVICE DISCONNECT CIRCUIT BREAKER
The utility service disconnect circuit breaker for the 200 amp
models are:
• Generac, Type 225AF, 2-pole
• 120/240VAC, 200A
• 50/60 Hertz
• Wire range: 300 MCM - 6 STR (Line), 250 MCM - 6 STR (Load)
• The conductor tightening torque is 375 in-lbs. (Line), 275 in-
lbs. (Non-essential Load and Generator Terminals)
Conductor Tightening
Torque
275 in-lbs.
UTILITY LUGS
GENERATOR
LUGS (E1 & E2)
LOAD LUGS (T1 & T2)
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