Siemens 21-115532-001 manual Protective Measures, Control Connections, Introduction

Models: 21-115532-001

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PROTECTIVE MEASURES

INTRODUCTION

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PROTECTIVE MEASURES

Bypass Arrester. All JFR regulators are equipped with a properly sized arrester, connected externally between the 'S' and 'L' line terminals. The arrester is provided to protect the series winding of the regulator from line surges. By itself, the bypass arrester does not provide lightning protection for the regulator.

Lightning Protection. The number of lightning arresters used will be a discretionary decision on the part of the user, considering such factors as isokeraunic level and degree of risk of damage to be accepted. The minimum recommended lightning protection consists of a properly sized arrester between the 'S' or 'L' bushing and ground on a single phase or a wye connected system. A delta connection system requires the use of two arresters to accomplish minimum protection levels. Additional protection can be obtained with the use of arresters at both the 'S' and 'L' terminals in single phase or wye systems and on all three terminals on a delta system.

For best results, install lightning arresters on the mounting lugs adjacent to the bushings near the top of the tank. The lugs are 0.5 - 13NC located on 2.5 inch centers. Ground the arrester(s) and the regulator tank solidly to the same ground connection. Be careful to keep the ground lead connections as short as possible.

Thru Fault. Type JFR regulators are rated under condition of thru-faults per ANSI C57.15.

The user is advised to provide for additional source imped- ance, bus sectionalizing or other means of limiting the avail- able thru-fault current if these criteria are exceeded at the installation.

Figure 5A

For this purpose, it is necessary to use the nameplate drawing and control diagram found in the control enclosure.

1.Refer to the Nameplate. The P2 column indicates the correct connection for lead P2 based on the system voltage. Using the applicable control diagram, the terminal designation of the nameplate can be cross referenced to the proper terminal on the 19-pin terminal block.

2.Depending on the regulator, there may be a second nameplate column indicating that lead U2 should also be connected. If so, the U2 column indicates the correct connection for lead U2 based on the system voltage Using the applicable control diagram, the “U” terminal designation of the nameplate can be cross referenced to the proper terminal on the 19-pin terminal block.

CONTROL CONNECTIONS

Many regulators can be used at several different nominal system voltages. It is therefore necessary to assure that the regulator is properly connected at the 19 pin upper terminal block for the system voltage on which the particular regulator will be used.

3.For regulator equipped with fans for forced-air cooling, another set of connections will be shown.

NOTE Matters specifically relating to the Accu/StatTM control used in conjunction with the regulator are not included in this manual. Refer to the appropriate control instruction manual.

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Siemens 21-115532-001 manual Protective Measures, Control Connections, Introduction