Installing the VR3 Voltage Regulator On SR4 Generators{4467} Caterpillar

Introduction

This instruction provides the parts and information needed to retrofit a VR3 Voltage Regulator into all SR4 generators.

The VR3 voltage regulator is installed using either a 7C9120, 7C9121 or 7E5031 Bracket depending on the type of terminal box design.

The bracket used, and the method of installation, is dependent on the terminal box design of the generator.

The 7C9120 and 7C9121 Brackets can be installed by welding into position or by drilling four holes and using screws and nuts to secure.

Use the Mounting Bracket Usage Chart to find your particular application before proceeding to "Preparation Before Installation" section of this instruction.

Do not perform any procedure, outlined in this publication, or order any parts until you read and understand the information contained within.

Reference: SENR3473, VR3 Voltage Regulator Supplement for SR-4 Generators (10/12 Lead, Self-Excited).

SENR3904, VR3 Voltage Regulator Supplement for SR-4 Generators (4/6/Lead, Self-Excited).

SENR3905, VR3 Voltage Regulator Supplement for SR-4 Generators (Permanent Magnet Excited).

Service Magazine (December 21, 1987), Improved VR3 Voltage Regulator Available for Earlier Generators.

Service Manual, SENR3985, "SR4 Generator With VR3 or VR4 Voltage Regulator".

SENR4794, Schematic, "Connection Diagram: SR4 Generators, VR3 and VR4 Voltage Regulator Options".

Mounting Bracket Usage Chart

Preparation Before Installation of VR3 Voltage Regulator

Read and understand all safety precautions and warnings before operating or performing any service or repair on this product.

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When servicing or repairing electric power generation equipment: * Make sure the unit is off-line (disconnected from utility and/or other generators power service), and either locked out or tagged DO NOT OPERATE. * Make sure the generator engine is stopped. * Make sure all batteries are disconnected. * Make sure all capacitors are discharged.

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When power generation equipment must be in operation to make tests and/or adjustments, high voltage and current are present. Make sure the testing equipment is designed for and correctly operated for the high voltage and current tests being made. Improper test equipment may fail and present a high voltage shock hazard to its user.

Protecting the Regulator and Other Generator Components During Parts Installation

Before any parts installation the unit should be prepared to prevent:

* Any metallic debris (when installing by drilling method) from accumulating on other components.

* Any welding splatter (when installing by welding method) from contacting other components and/or contacting any combustible areas or surfaces.

Electrical Connection Preparation

All electrical connections are to be made directly to parent materials only.

* Any paint, corrosion or lubricant must be removed from mating surfaces prior to connection.

* Use only plated (or otherwise corrosion protected) hardware to make connections.

Necessary Parts

NOTE: The following parts (not included with the 7C9120, 7C9121 and 7E5031 Brackets) are required to install the VR3 Regulator into the appropriate bracket and to secure the bracket to the terminal box. They must be ordered separately.

Removing the Existing Voltage Regulator and Installation of (If Equipped) Excitation Transformer (4/6 Lead SE)

1. Remove access cover.

2. Remove existing regulator and mounting bracket.

NOTE: If equipped with excitation transformers proceed to Step 3, if NOT so equipped, proceed to Step 5.

3. Remove excitation transformers (if so equipped) and retain mounting hardware.

4. Install new Excitation Transformer (4/6 Lead SE) using the same hardware that mounted the original transformers.

5. Replace all bolts that fastened regulator to generator frame.

* This will help protect interior of the generator frame from foreign material and also provide a bolt to secure the ground strap when installing the VR3 Regulator.

6. Identify all leads before disconnecting.

Installation of the 7C9120 or 7C9121 Bracket

Before installation be sure you are installing the correct bracket according to the type of terminal box mounting (top mounted or saddle mounted). Refer to the Mounting Bracket Usage Chart for the correct bracket.

Installation of Bracket by Welding

1. Remove (depending on type of housing) side panel and/or top five louvers.

2. Place bracket (1) into position and location shown.

3. Clamp bracket (1) firmly to back side of terminal box frame (2).

4. Weld (on backside) bracket (1) to terminal box frame (2) using evenly spaced stitch welds, approximately 50.8 mm (2.0") in length.

Installation of Bracket by Drilling

1. Remove (depending on type of housing) side panel and/or top five louvers.

2. Place bracket (1) into position and location shown.

3. Clamp bracket (1) firmly to back side of terminal box frame (2).

4. Drill four evenly spaced 6.731 mm (0.265") holes through terminal box frame (2) and bracket (1).

5. Fasten bracket (1) and terminal box frame (2) together using four 4B1282 Screws and four 6V8185 Nuts. All nuts are to be finger tight (until after next step).

6. Install (temporary) the panel that covers regulator. Check for clearance between the 4B1282 Screw head and panel.

If additional clearance is needed, remove the parts and countersink the holes in the terminal box frame slightly, to allow the 4B1282 Screws to seat flush (level).

7. Reinstall the bracket, if removed to countersink, with 4B1282 Screws and 6V8185 Nuts.

8. Tighten all hardware at this time.

Installation of 7E5031 Bracket

1. Remove (depending on type of housing) side panel and/or top five louvers.

(A) Front View and (B) Top View of 7E5031 Bracket showing the two predrilled mounting holes and one slotted hole for mounting screws and bolt.

2. Place 7E5031 Bracket (2) into position and location shown.

NOTE: The 7E5031 Bracket is predrilled for the two 1H8294 Screws (3) and slotted for the 8T9043 Bolt (4).

3. Drill two 7.5 mm (.30 in) diameter holes through the terminal box frame (1).

4. Fasten bracket (2) to terminal box frame using two 1H8294 Screws (3), two 8P6099 Spacers (5), two 8T4205 Washers (6) and two 6V8185 Nuts (7).

NOTE: All nuts should be finger tight until after all hardware is installed.

5. Install 8T4224 Washer (8) and 8T9043 Bolt (4) finger tight at this time.

6. Install (temporary) the panel that covers regulator.

* Check for clearance between the 1H8294 Screw (3) heads and panel.

* If additional clearance is needed, countersink the holes in the terminal box frame slightly to allow the 1H8294 Screws to seat flush (level) on the frame (1).

7. Reinstall the bracket, if removed to countersink the frame mounting holes, using two 1H8294 Screws (3), two 8P6099 Spacers, two 8T4205 Washers and two 6V8185 Nuts.

8. Tighten all hardware at this time.

Installing the VR3 Voltage Regulator

Installing Into 7C9120 or 7C9121 Bracket

1. Install the VR3 voltage regulator into the 7C9120 or 7C9121 Bracket (1) in the position and location shown. Use the following hardware, as shown at three locations (B), to mount the VR3 voltage regulator.

* 2 - 332075 Washers (2).

* 1 - 7C5709 Sleeve (3).

* 1 - 7C5708 Grommet (4).

* 2 - 6J8696 Shims (5).

* 1 - 6V8185 Nut (6).

2. Install 8J1256 Clip (7) to the VR3 regulator, at location (A), to secure and support the regulator wiring harness. Use two 8T4205 Washers (8) and one 6V8185 Nut (6).

3. Install and connect a 16 AWG ground strap between locations (C) and (D).

NOTE: Location (D) requires an appropriately sized ring terminal for an 8-32 stud.

Installing Into 7E5031 Bracket

1. Install the VR3 regulator into 7E5031 Bracket (1) in the position and location shown. Use the following hardware, as shown at three locations (B), to mount the VR3 voltage regulator.

* 2 - 332075 Washers (2).

* 1 - 7C5709 Sleeve (3).

* 1 - 7C5708 Grommet (4).

* 2 - 6J8696 Shims (5).

* 1 - 6V8185 Nut (6).

2. Install 8J1256 Clip (8) to VR3 regulator, at location (A), using two 8T4205 Washers (9) and one 6V8185 Nut (6) to secure and support the regulator wiring harness.

3. Install and connect a 16 AWG ground strap between locations (C) and (D).

NOTE: Location (D) requires an appropriately sized ring terminal for an 8-32 stud.

Attachments

Partial view of regulator. 1. Voltage droop potentiometer. 2. Remote level potentiometer. 3. Jumper (If not using remote level potentiometer).

Voltage Level Control

If equipped with a remote voltage level control, remove jumper (3) and replace existing potentiometer (2) with a 7C4471 Potentiometer.

NOTE: Remove jumper wire (3) between terminals 4 and 7.

Refer to "Reference" section of this instruction, for the appropriate Service Manual Supplement or module.

Voltage Droop

If equipped with voltage droop, remove 6L7004 Potentiometer (1) from old regulator and install in the location (hole) provided on the 7C9120, 7C9121 or 7E5031 Bracket.

Manual Voltage Controls

If the voltage regulator being replaced was used with a manual voltage control, check the type of generator [Self Excited (S.E.) or Permanent Magnet (P.M.] and the part number for the manual control.

The S.E. VR3, 9Y8400 or 7C2663, requires a 7C2700 Manual Control.

The P.M. VR3, 7E8261, 7E8262 or 7E8263, requires a 5N0591 Manual Control.

For wiring the VR3 to its respective control, refer to SENR4794, "Connection Diagrams: SR4 Generators, VR3 and VR4 Voltage Regulators Options".

RFI Filters

If the voltage regulator being replaced was used with an RFI Filter, then the RFI Filter needs to be replaced with an RFI Filter that is compatible with the VR3 Voltage Regulator.

When the replacement VR3 is a 9Y8400 or 7E8261, a 9Y0968 RFI Filter is required.

When the replacement VR3 is a 7C2663 or 7E8262, a 7E5034 RFI Filter is required.

For wiring the RFI Filter to the VR3 regulator, refer to SENR4794, "Connection Diagrams: SR4 Generators, VR3 and VR4 Voltage Regulators Options".

Crosscurrent Compensation for Zero Droop

If the voltage regulators being replaced were on generators used in parallel operation and connected for crosscurrent compensation, refer to Engine Division Data Sheet, EDS75.5, for proper connections to the VR3 voltage regulators. In some cases, the addition of an isolation transformer in the droop transformer connection to the VR3 may be required.

KVAR Controllers

If a Basler SCP 250G KVAR Controller is used with a SR4 Generator, refer to Engine Division Data Sheet, EDS 75.4 for the correct interface connections to the VR3 Voltage Regulator.

Electrical Wiring Connections Schematics

NOTE: Choose the appropriate Regulator Wiring Connections wiring schematic before proceeding to "Voltage Control Initial Adjustment" section of this instruction.

NOTE: This schematic portion of the instruction can be attached to the generator for future reference.

9Y8400 Regulator Wiring Connections 10/12 Lead SE

SR-4 Generator Schematic (10/12 Lead, Self-Excited & 2 Fuse Type)

Use the schematic above to reconnect all electrical connections.

NOTE: Generator stator leads terminals T10, T11 and T12 to be connected to form the neutral lead (TO) on 12 Lead WYE connected generators. Delta connections only available with 12 lead generators. 4/6

7C2663 Regulator Wiring Connections Lead SE

SR-4 Generator Schematic (4/6 lead, self-excited).

Use the schematic above to reconnect all electrical connections. 10/12

7E8261 Regulator Wiring Connections Lead PM

SR-4 Generator Schematic (10/12 lead, permanent magnetic excited).

Use the schematic above to reconnect all electrical connections.

NOTE: Generator stator leads, terminals 10, 11 and 12 can be connected to form the neutral lead (T0) on twelve lead generators.

NOTE: VR3 PM regulator, terminal 26 is connected to PMG output and not to generator neutral (T0) as on previous regulators.

NOTE: If required, two PM Exciter fuses are needed. Use two 9Y6027 Fuses and two 7E8266 Fuse Assemblies. 4/6

7E8262 Regulator Wiring Connections Lead PM

SR-4 Generator Schematic (4/6 lead, permanent magnetic excited).

Use the schematic above to reconnect all electrical connections.

NOTE: Generator stator leads, terminals 4, 5 and 6 can be connected to form the neutral lead (T0) on six lead generators.

NOTE: VR3 PM regulator, terminal 26 is connected to PMG output and not to generator neutral (T0) as on previous regulators.

NOTE: If required, two PM Exciter fuses are needed. Use two 9Y6027 Fuses and two 7E8266 Fuse Assemblies. 4/6

7E8263 Regulator Wiring Connections Lead PM (Medium Voltage)

SR-4 Medium Voltage Generator Schematic (4/6 lead, permanent magnetic excited).

Use the schematic above to reconnect all electrical connections.

NOTE: VR3 PM regulator, terminal 26 is connected to PMG output and not to generator neutral (T0) as on previous regulators.

NOTE: If required, two PM Exciter fuses are needed. Use two 9Y6027 Fuses and two 7E8266 Fuse Assemblies.

Voltage Control Initial Adjustment

The following is a reproduction of Film-Instruction 7C5711 which is available thru normal parts ordering. In the interim use the following for adjustment procedures.

NOTE: This portion of the instruction can be attached to the generator for future reference.

Single Unit Operation

1. Remove the left side access panel of the generator.

2. Remove the sealing screws for access to the level and gain adjustment controls.

3. Turn the gain control to the left (counterclockwise) to zero, then turn the gain control five turns to the right (clockwise).

4. Perform required maintenance on engine before starting.

5. Start the engine and allow it to warm.

6. Increase engine speed to its full governed speed (high idle).

7. Observe the voltmeter reading if desired voltage is not indicated, set no load voltage with level control.

8. Close the circuit breaker and gradually apply full load. Adjust governor control until nameplate frequency is indicated on the Hertz meter or until an engine tachometer indicates rated speed.

9. (a) If voltmeter reading increases with full load applied, turn gain control counterclockwise.

(b) If voltmeter reading decreases with full load applied, turn gain control clockwise.

10. Remove load, adjust voltage level control if necessary to obtain full voltage.

11. Apply the load, observe voltmeter reading. Repeat steps 8 thru 11 until no load voltage equals full load voltage.

12. Replace the sealing screws in the level and gain access holes.

Voltage Adjustment-Parallel Operation

The voltage level and voltage droop adjustments determine the amount of circulating currents between paralleled generators.

Carefully matched voltage regulator adjustments will reduce the circulating currents.

Loads of 0.8 power factor (primary motors) require a generator voltage droop of approximately five percent (5%).

Voltage droop is expressed as the percentage of voltage change from no load to full load.

Use the same voltmeter to make adjustments on each unit to be paralleled.

1. Loosen the locknut on the voltage droop control and turn the droop control fully counterclockwise.

2. Adjust voltage and gain as described for Single Unit Operation.

3. With the engine running at high idle speed, turn the voltage droop clockwise about one-half (1/2) of full range.

NOTE: If driven load is to be unity power factor, set the voltage droop control on all generators at one-half of full range and proceed to Step 8. If driven load includes reactive load (motors) proceed to Step 4.

4. Readjust the voltage level control until the voltage is about five percent above desired voltage.

5. Apply full load including reactive load.

NOTE: If a generator is paralleled with other generators, the voltage droop of each generator must be the same to satisfactorily divide reactive load.

6. Readjust the voltage droop control to obtain desired voltage with full load at 0.8 power factor.

7. Repeat Steps 4, 5 and 6 on each generator to be paralleled until line voltage is equal to desired level loaded and no load voltage is approximately five percent above rated voltage.

8. Parallel generator at no load. Adjust level control to minimize circulating current.

9. Apply load. If the sum of the amps of the individual generator amperes exceeds the total amperes going to the load by 10 percent at full load, adjust voltage droop controls to share current proportionately between generators.

NOTE: DO NOT exceed rated ampere load on any single generator.

10. Tighten the locknuts on droop control and install the access cover.