Section 2 General Information; Equipment Description; Automatic Transfer Switch; Transient Voltage Surge Suppression - Generac Power Systems HTS Owner's Manual

General Information
Section 2
2.1 — Equipment Description
2.1.1— Automatic Transfer Switch
The commercial transfer switch range (HTS) is designed
to operate in conjunction with the Power Manager Gxxx
and Hxxx series of Generator controllers. The transfer
switch has a simple 2-wire communications link to the
Generator controller and can thus be mounted remote
from the Generator.
Utility voltage is monitored by the HTS and fed back to
the engine generator control panel for comparison
against setpoints, used to determine if the Utility voltage
is "good."
Operation of the switch is instigated by the generator
control panel, however, all aspects of TDN timing or
inphase transfer are handled locally at the HTS. The HTS
monitors a single phase of the Generator voltage in order
to perform inphase transfers.
All timers and voltage setpoints are programmable in the
G/H control panel. Some of the decisions are made by
the HTS itself so the appropriate parameters are passed
to the HTS via the communication link. If the communica-
tion link were to break, the HTS will still function. It will
monitor the Utility and Generator voltages and make the
transfer determination itself, rather than being com-
manded by the generator control panel. It will either use
the last parameters sent, or, if no parameters were ever
sent (communications were never established), it will
take its settings from onboard DIP Switches and a set of
resident parameters.
The automatic transfer switch is used for transferring crit-
ical electrical load from a normal (utility) power source to
a standby (emergency) power source. Such a transfer of
electrical loads occurs automatically when the normal
power source has failed or is substantially reduced and
the standby source voltage and
frequency have reached an acceptable level. The trans-
fer switch prevents electrical feedback between two dif-
ferent power sources (such as the normal and standby
sources) and, for that reason, codes require it in all
standby electric system installations.
2.1.2— Transient Voltage Surge Suppression
The Transient Voltage Surge Suppression (TVSS) is pro-
vided to protect the load from electrical surges and/or
transient voltage spikes. This device is physically located
on the side wall of the enclosure. It is electrically con-
Automatic Transfer Switch Owner's Manual
nected to the load side of the transfer switch. A 30 amp
circuit breaker is provided to disconnect the TVSS from
the transfer switch for maintenance or replacement.
The TVSS is made up of multiple solid state Metal Oxide
Varistors (MOV) connected in parallel for each mode of
protection. These devices are equipped with integrated
short circuit and individual component level fusing. They
are self-reseting and fully automatic.
2.1.2.1—Modes of Protection
The TVSS provides protection on all modes:
• Single Phase (6): L-L, L-N, L-N, L-G, L-G and NG.
•
Three Phase (10): L-L, L-L, L-L, L-N, L-N, L-N,
L-G, L-G, L-G and N-G.
2.1.2.2—Ratings
• Surge Capacity: 200 kA maximum.
2.1.2.3—Certification
The TVSS is UL recognized to the requirements of UL
1449 3rd edition.
2.1.2.4—TVSS Disconnect
Each TVSS is provided with a disconnect. The discon-
nect is a 30 amp circuit breaker, 2-pole for single phase,
and 3-pole for three phase. This is to allow replacement
of the TVSS module without interruption of the electrical
supply to the load.
IMPORTANT: Turn on TVSS disconnect circuit breaker
when the procedure is complete. If circuit breaker is not
turned on, the TVSS module will not provide surge protec-
tion for customer load.
2.1.2.5—Status Indicators
Each TVSS module has comprehensive, solid state, con-
tinual visual status monitoring of each protection mode
present. There are two LEDs provided, located on the
cover of the module. The green LED (left side) is used to
indicate that the TVSS module is energized and in work-
ing order. The red LED (right side) will turn on in the
event the suppressor capability is exceeded or if there is
an internal safety component activating. When both the
green and red LEDs are on, there is a neutral to ground
fault.
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