Howard SVR1 Regulator - Manual (Page 7)

Switch-Pad™ SVR-1 Step Voltage Regulator
Document No. 2.4.114
Revision: 03
Issued: March, 2012
7 Copyright © 2012 Howard Industries, Inc.
INSTAllATION (Continued)
CONTROl CONNECTIONS
SVR-1 regulators can be used on several different system
voltages. A cover-mounted terminal block (Figure 3) is
provided, so that control and fan leads (if present) can be
connected as necessary to accommodate the particular
system voltage to be regulated.
SVR-1 regulators may be operated at less than the rated
voltage as indicated on the nameplate. When operated at
less than rated voltage, regulator kVA is reduced, except
when operating a 7.62kV regulator at 7.2kV.
In order to properly connect the control leads, it is
necessary to refer to the control diagram found on the
nameplate (Figure 2). The control diagram will aid in the
identification of the appropriate terminal connections.
Follow the instructions listed below:
1. Referring to the regulator nameplate diagram,
connect the “PS” lead as indicated for the applicable
system voltage.
2. For some regulators the nameplate will indicate a
connection for the “MS” lead. Connect this lead as
indicated.
3. For regulators equipped with cooling fans,
connect fan leads as indicated.
bY-PASS SURGE ARRESTER
Each SVR-1 regulator is equipped with an appropriately
sized by-pass surge arrester connected between the
“S” and “L” high-voltage bushing terminals. This by-pass
arrester (sometimes refered to as the “series arrester”)
is provided to protect the series winding of the regulator
from damage due to line surges. The by-pass arrester
does not provide complete lightning protection for the
regulator. Improved lightning protection can be provided
as described below. Refer to the connection diagrams on
page 9.
lIGHTNING PROTECTION
Lightning protection can be provided by adding appropri-
ately sized surge arresters to the “S” and “L” bushing ter-
minals. These arresters (called “shunt arresters”) should
be mounted on the regulator tank adjacent to both the
“S” and “L” bushings using the supplied mounting provi-
sions. The top lead of each arrester should be connected
to the adjacent bushing terminal. Arrester grounding is
achieved through the arrester mounting brackets. Refer
to the connection diagrams on page 9.
THROUGH FAUlT
SVR-1 regulators are designed to withstand through-fault
currents of 25 times the nameplate rated ONAN current
as described in IEEE Standard C57.15-2009.
In order to limit through-fault current to acceptable levels
as described above, the user should consider the applica-
tion of additional source impedance, bus sectionalizing,
or other methods.
50 HERTZ OPERATION
Regulators can be modified at factory for 50 Hertz
operation with appropriate derating of voltage. Contact
the Howard Industries Regulator Division for information
about regulators specifically designed for 50 Hertz.
operation.