INSTRUCTION MANUAL For HIGH CURRENT OUTPUT UNIT MODEL EPOCH-20

It is essential that this instruction book be read thoroughly before putting the equipment in service.

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APPRECIATION

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We are indebted to those who have given their time and advice in the preparation of this instruction manual. It is MULTI-AMP Corporations's goal to continually improve its products and services to its customers. To that end, we welcome any suggestions or contributions our customers would care to offer.

IMPORTANT The information and data contained within this instruction manual are proprietary with MULTI-AMP Corporation. The equipment described herein may be protected by one or more U.S. letters patent. MULTI-AMP specifically reserves to itself all rights to such proprietary information as well as all rights under any such patent, none of which is waived by the submission of this instruction manual to anyone. The recipient, if a Government agency, acknowledges that this instruction book and the equipment described were procured with "Limited Rights" to technical data as described in ASPR 9-203 (b).

Copyright MULTI-AMP Corporation, 1988

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TABLE OF CONTENTS SectionPage I. GENERAL DESCRIPTION AND SPECIFICATIONS Bulletin II. THEORY OF OPERATION 1

A. Description of Controls 1

B. Back Panel 1

C. Selection of Output Taps 2

D. Overload Capability 2 III. OPERATING PROCEDURES 3

A. Operation of EPOCH-20 Output 3

B. Operating With More Than One EPOCH-I/10 3 - 4

C. Operating With One or More EPOCH-20's 5 IV. SCHEMATIC AND PARTS LIST

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DESCRIPTION OF CONTROLS This section of the instruction manual describes the function of the various switches and output terminals, which are located on the EPOCH-20. POWER ON/OFF Switch Used to energize input to Model EPOCH-20. Also functions

as a circuit breaker for input protection. BURDEN LOW/HIGH Switch

This switch is used to select either a 300 VA or 600 VA output, depending on the burden of the relay being tested.

MODE EPOCH-I/EPOCH-20 Switch

This switch is used in selecting which current output bindingposts are to be energized. When in the EPOCH-I/10 position, the EPOCH-I/10 Current Output Binding Posts are used to supply current (used when higher resolution at lowcurrents and low VA are desired). When in the EPOCH-20 position, the EPOCH-I/10 Current Output Binding Posts are inoperable and the EPOCH-20 Binding Posts are energized (used for high current or high VA applications).

BACK PANEL The input line connector, ground terminal and interconnecting plugs are mounted on the back of the unit. The following is a description of each item. AC POWER Connector andInput Cord

To supply maximum rated output, the EPOCH-20 requires 120 volts at 30 amperes. Due to this requirement, theEPOCH-20 is supplied with a special input cord and input power connector.

Safety GROUND For proper operation of the test system, it is ABSOLUTELY

NECESSARY to interconnect the ground terminals of theEPOCH-20 and the EPOCH-I/10 Control Unit. These terminals can be found on the back panels. Leads areprovided for this purpose.

EPOCH-20 CONTROL Interconnect

It is necessary to properly interconnect the EPOCH-20 to the EPOCH-I/10 Control Unit using the control cable assembly. Interconnect the EPOCH-I/10 connector labeled "EPOCH-II CONTROL" to the EPOCH-20 "CONTROL" connector.

Signal INPUT Interconnect A special Signal INPUT interconnect cable is supplied to

connect the EPOCH-I/10 Control Unit interconnect labeled EPOCH-II SIGNAL to the EPOCH-20 Signal INPUT connector.

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SELECTION OF OUTPUT TAPS The EPOCH-20 has six (6) current output taps to adapt the output to a wide range of load impedances and current requirements. The output is controlled by the EPOCH-I/10 Control Unit (see Operating Procedures on page 3, for details concerning setting test currents etc.). The EPOCH-20 may be operated most advantageously by using the tap which most closely equals the desired test current. In this way you are insured of the most resolution and volt-ampere compliance. It should also be noted that each tap has a ten percent (10%) overrange limit. This provides some flexibility when performing instantaneous pickup tests at current levels equal to the selected output tap. For example, on the 40A tap, it can be overranged to 44 amperes before making a tap change to 50A tap, etc. NOTE: Under certain load conditions, overranging could cause the d.c. overcurrent protection to

trip, or line current to exceed rating and cause your source breaker to trip. OVERLOAD CAPABILITY The EPOCH-20 has two VA ranges. In the LOW BURDEN position 300VA is available, and in the HIGH BURDEN position 600VA is available. Provided the voltage is sufficient to push the current through the impedance of the load circuit, each range is capable of supplying its rated current for three minutes (at specified accuracy), to be followed by a 15 minute cool down period. Each tap may be overloaded by demanding more than rated voltage. The outputs may be overloaded until distortion of the current waveform results. The percent of overload is dependent upon which tap you are using and the load under test. The time on, time off will be reduced slightly dependent upon the percent of overload. Should the unit be overloaded for too long, a thermal overload shutdown will occur. In the event of a thermal overload shutdown, leave the power ON, so that the fans can cool down the unit. In the event of low input voltage, outputs may be derated under certain conditions. Under normal test conditions, with the output current in phase with the input voltage, the input voltage can vary + 10% of 115 volts without effecting the VA rating of the unit. The only exception is the 170A tap which is -5% + 10% of 115 volts. In the worst case, the outputs may be derated to 90% of the rated output tap voltage, when the output current is 90 degrees out of phase with the input voltage, and the input voltage is -10% of 115 volts.

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OPERATING PROCEDURES After careful review of the "Theory of Operation Section", of both the EPOCH-I/10 and EPOCH-20 instruction manuals, the operator should now be ready to begin operating this equipment. This section describes the basic operating procedures and applications. A. Operation of EPOCH-20 Output

With the units properly interconnected and connected to the proper power sources, to operate the EPOCH-20 output proceed as follows:

1. Select the appropriate current output tap. Using the leads supplied with the EPOCH-

20, connect the leads to the relay under test.

SPECIAL NOTE: When the EPOCH-20 is on, there is an open circuit potential across the output taps that could present a shock if not properly handled. To insure safety, connect the load first before turning the unit on.

2. It is good practice to power up the EPOCH-I/10 first, before powering up the

EPOCH-20. This will eliminate any possible noise conditions, which could exist on the Signal Input to the EPOCH-20.

3. Depending upon the burden of the relay under test, the Burden Low/High Switch

should be switched to the appropriate position.

4. Switch the MODE Switch to the EPOCH-20 position. The unit is now ready for operation.

CAUTION: When the EPOCH-20 is on, remember, the output is rated up to

600VA, which means that potentially lethal voltage can be present under certain conditions.

5. To set a test current, simply press the EPOCH-I/10 Increase Pushbuttons for the

current channel. The output will be indicated on the EPOCH-I/10 current channel digital display. The EPOCH-20 current output will follow the settings on the EPOCH-I/10 Control Unit to include PHASE SHIFTING, HARMONIC OUTPUT, ON/OFF, and OUTPUT INITIATE CONTROLS.

NOTE: The resolution of the EPOCH-I/10 current channel display is determined by

the EPOCH-20. When the male plug of the test lead is inserted into the desired output tap, a sensing circuit senses which tap is being used and moves the decimal point accordingly. Two output taps cannot be used simultaneously. The unit will sense this condition and will invalidate the operation of the EPOCH-20.

B. Operation With More Than One EPOCH-I/10

This section describes the basic operation procedures for using an additional EPOCH-I/10 with the EPOCH-I/10 and EPOCH-20 System.

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1. Current Sources - Parallel Operation

It is unlikely that the EPOCH-20 will need assistance for more current from additional EPOCH-I/10's in parallel operation, as would be the case if just two EPOCH-I/10's were in use. However, it may be desireable to parallel an additional EPOCH-I/10 current channel with the EPOCH-20 and use the EPOCH-I/10 current channel as a vernier adjustment. If so, parallel the EPOCH-I/10 (not the EPOCH-I/10 Control Unit) and the EPOCH-20 current outputs as described in the EPOCH-I/10 Manual on page 2-15. Make sure that the EPOCH-I/10's are properly interconnected as described in the EPOCH-I/10 Manual on page 2-1.

2. Current Sources-Harmonic Restraint Test

To perform harmonic restraint test on current differential relays requires one EPOCH-I/10 and EPOCH-20 Test System, to provide the fundamental test current, and the one additional EPOCH-I/10 to supply either the second or third harmonic test current. For those relays that require a polarization current, the EPOCH-20 can supply the high currents required to polarize the relay.

To set up the units for harmonic restraint testing, use the following procedure:

1. Parallel the EPOCH-20 with the EPOCH-I/10 (not the Control Unit) using the

procedure as outlined previously under Section B above.

2. Connect a pair of current leads from the EPOCH-I/10 (not the Control Unit) and the EPOCH-20 to the relay, so that the current from each output will be in parallel with one restraint and one operating coil of the relay. Check to insure both commons share the same relay terminal.

3. Switch the EPOCH-I/10 Power ON Switches ON. Switch the EPOCH-20 Power

ON.

4. Set-up the EPOCH-20 output for operation as outlined previously under Section A.

5. Switch the HARMONIC Selector Switch on the EPOCH-I/10 (not the Control Unit) to the desired harmonic, second or third.

6. Press the EPOCH-I/10 current output INITIATE Switches. The INITIATE Switch

lamps should glow.

7. Set the appropriate harmonic current on the EPOCH-I/10 (not the Control Unit). It is recommended that one ampere of harmonic current be set.

8. Initiate outputs by pressing the INITIATE Control Switch. Increase the fundamental

current of the EPOCH-I/10 Control Unit until the relay operates. To calculate the percent of harmonic restraint use the appropriate equation below.

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General Electric BDD

% of Harmonic = 2nd Harmonic Current x 100

Restraint (Fundamental)2 + (2nd Harmonic)2

Westinghouse HU

% of Harmonic = 1.2267 x 2nd Harmonic Current x 100 Restraint (Fundamental)2 + (2nd Harmonic)2

C. Operation With One or More EPOCH-20's

This section describes the operating procedures for using additional EPOCH-20's for high current or high VA applications.

1. EPOCH-20 Currents in Parallel

It may be desireable to parallel an additional EPOCH-20 in order to achieve more current or VA than is available from a single EPOCH-20. The two EPOCH-20 High Current units (and their associated EPOCH-I/10 Control Units) are paralleled as described earlier on page 4. Then interconnect the EPOCH-I/10 Control Units and set one unit up as Master Unit (see EPOCH-I/10 Manual page 2-13). Be sure to interconnect the EPOCH-I/10 ground terminals together.