Warning, Installation – Howard SVR1 Regulator User Manual

Page 5

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SVR-1 Step Voltage Regulator

Document No. 2.4.114

Revision: 03

Issued: March, 2012


Copyright © 2012 Howard Industries, Inc.


An SVR-1 regulator can regulate the voltage on a single-

phase circuit or one phase of a delta- or wye-connected

three-phase circuit as described below and as illustrated

in the connection diagrams on page 9.

One SVR-1 regulator in a single-phase application

Three SVR-1 regulators connected in a grounded wye

configuration on a four-wire three-phase system

Three SVR-1 regulators connected in a delta

configuration on an ungrounded three-wire three-

phase system

Two SVR-1 regulators connected in an open delta

configuration on an ungrounded three-phase system



Before connecting the regulator, the following checks

should be made:

1. Check the oil level sight gauge for proper oil level (top

oil level visible in gauge). Add ASTM D-3487 Type 2

oil, if the level is found to be low. Check for visible

signs of oil leaks.

2. Measure the dielectric strength of the oil per ASTM

D-877. If found to be below 24 kV, the oil should be

filtered and retested (NOTE: This test is not necessary

if the regulator is being installed immediately after

receipt from the factory.)

3. Measure power factor from each bushing terminal

to tank ground. The reading should be less than 2.0


4. Inspect the porcelain bushings for damage or signs

of oil leaks. If it is suspected that moisture may have

entered the regulator, test the oil per ASTM D-3487

(Type 2). A positive indication for moisture will require

that the regulator be dried and the oil filtered before

placing into service.


Typical regulator nameplate


Due to the possibility of neutral shift, three SVR-1

regulators should not be connected together in an

ungrounded, wye-connected, three-wire, three-phase


5. Inspect the by-pass arrester (and shunt arresters, if

present) for damage. Damaged arresters should be

replaced with new arresters of the same voltage rat-


6. Refer to the nameplate (Figure 2) and confirm that

the regulator is connected for the proper output volt-

age, motor voltage, and control panel voltage. If not,

follow the procedure on pages 6 and 7 to make the

necessary connections.

7. Make absolutely sure that the regulator tap changer

is in the neutral tap position. This can be accom-

plished by observing that both of the following

conditions have been met: 1) The pointer on the tap

position indicator is pointing to “zero,” and 2) the

neutral indicator is continuously illuminated. (The

control panel can be powered from a 120 Volt exter-

nal source.)