Warning, Danger, Maintenance (continued) – Howard SVR1 Regulator User Manual

Page 14

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Document 2.4.114

SVR-1 Step Voltage Regulator

Copyright © 2012 Howard Industries, Inc.

Document No. 2.4.114

Revision: 03

Issued: March, 2012


The control panel is hinged and may be removed

completely from the regulator control enclosure. It is

not necessary to bypass or de-energize the regulator to

remove the control panel. To remove the control panel,

remove the two wing nuts on the Connector Terminal Strip

(CTS) and disconnect the CTS (Figure 10). The spring-

loaded shorting contacts in the CTS will automatically

maintain the necessary electrical connections to allow

removal and replacement of the control panel without

de-energizing it.

CTS terminal designations are as follows:

“PS” – Panel source

“MS” – Motor source

“G” – Ground

“CO” – Current transformer negative (–)


– Current transformer positive (+)

“DHR” – Drag hand reset


– Lower

“R” – Raise

“NS” – Neutral switch

“OC” – Operations counter


Determine the condition of the insulating fluid using the

following procedure:

1. Withdraw a sample of the insulating fluid using the

sampling device located in the drain valve at the

bottom of the tank.

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. Other tests such as

“neutralization number,” “interfacial tension,” and

“power factor” are also useful and may be desired by

some users.

3. Add oxidation inhibitor (2,6-ditertiary-butyl-

para-cresol, DBPC) to the insulation fluid at a

concentration of 0.2 to 0.3 percent, to replace

inhibitor that is naturally depleted over a period of a

few years.


Internal inspection, while not absolutely necessary, will

help identify problems that could cause future service


1. Untank the regulator using the following procedure:

Remove the regulator from service as described

on page 12.

Move the regulator if necessary to provide

adequate working room and the necessary vertical

clearance to lift the internal assembly out of the

tank. Be careful to avoid overhead lines.

Operate pressure relief valve to vent regulator

If the regulator is not operating properly, the first step in

troubleshooting should be the replacement of the control

unit with one known to be in good operating condition.



Dangerous voltage is present at the Connector

Terminal Strip and the motor capacitor terminals.

Contact with these voltages inside the control

enclosure can cause death or serious personal injury.


: Connector Terminal Strip (CTS) located in

control enclosure.


Exercise extreme caution when moving the regulator.

Contact with energized overhead lines will cause death,

serious personal injury, and property damage.